During any flight, a pilot will encounter several different flavors of visibility. This includes flight visibility, ground visibility, prevailing visibility, tower visibility, runway visual range, and vertical visibility.

But wait, is vertical visibility even a legitimate visibility? Actually, it’s a bit of a misnomer and not a true measure of visibility in the traditional sense. Vertical visibility is a close cousin to ceiling. That is, it represents the distance in feet a person can see vertically from the surface of the Earth into an obscuring phenomenon, or what is called an indefinite ceiling. What isn’t obvious is how vertical visibility is determined, and how this is different from a definite ceiling.

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It’s arguable that an indefinite ceiling is perhaps the most misunderstood phenomenon reported in a routine (METAR) or special surface (SPECI) observation. Forecasters will add vertical visibility in a terminal aerodrome forecast (TAF) as illustrated in the image below for Bradford Regional Airport (KBFD) in Pennsylvania. Whether this occurs in a METAR or TAF, vertical visibility is coded as “VV” followed by a three-digit height in hundreds of feet above the ground level. For example, you may see “VV002,” which is a vertical visibility of 200 feet. While a definite ceiling can be broken or overcast, a vertical visibility always implies the sky is completely covered. Let’s explore the difference between a definite and indefinite ceiling and the operational considerations.

Automated Observations

In the early days, human weather observers used to employ what were called “pilot balloons” to estimate the ceiling height. Essentially the balloon was launched by the observer and, given the balloon’s known rate of ascent, they watched the balloon enter the base of the clouds and measured the time it took using a stopwatch to determine the ceiling height. Then new technology emerged called a rotating beam ceilometer that measured the height of clouds. While it was more effective than launching a balloon, this method was phased out around 1990 and replaced with the laser beam ceilometer, the technology still widely used today.

The task of walking outside and assessing the height of clouds is generally a thing of the past given that this technology is incorporated into the automated surface observing system (ASOS) or automated weather observing system (AWOS) present at many airports throughout the U.S. The trained observer simply logs in to the ASOS (or AWOS) and makes their observation based on the data gathered and reported by the automated system. Then the observation is edited and augmented by the observer as necessary. Depending on the airport, this process may be completely automated.

In all honesty, making an estimate of the height of the cloud base isn’t the difficult part. What’s difficult is to provide a representative description of the amount of cloud coverage (e.g., few, scattered, broken, or overcast) in the airport’s terminal area. A laser beam that points straight up may easily miss a scattered or broken cloud deck. To alleviate this issue, the automated systems process the data over a given amount of time since clouds are generally moving through the sensor array area. It was found that a 30-minute time period provided a representative and responsive observation similar to that created by a trained observer. The most recent 10 minutes of sky cover and ceiling height are double weighted using a harmonic mean. (A harmonic mean is used in the visibility and sky cover algorithms rather than an arithmetic mean because it is more responsive to rapidly changing conditions such as decreasing visibility or increasing sky coverage/lower ceiling conditions.) In the end, the goal is to provide an observation representative of the airport’s terminal area, which is the area within 5 sm from the center of the airport’s runway complex. Visibility, wind, pressure, temperature, etc., all have their own harmonic means accordingly.

In our everyday experience, we know that many cloud decks observed from the ground have a very well-defined base. For an untrained observer, it might not be a simple task to determine their height. However, it’s easy to pick out where the base of the cloud starts. Even in these cases, the cloud decks may vary in height and multiple cloud layers may exist. Visually, that may be more difficult to discern for the untrained eye, but automated systems do a reasonable job making that observation. In a convective scenario, it is not unusual to see multiple scattered and broken cloud heights. For example, at the West Michigan Regional Airport (KBIV) the following was observed:

KBIV 122353Z AUTO 08011KT 4SM RA BR FEW011 SCT048 OVC065 19/18 A2972

This observation includes three definite cloud layers, which are a telltale sign that a convective environment is in place even before the first lightning strike.

Nuts and Bolts

An ASOS continuously scans the sky. To determine the height(s) of the clouds, the backscatter returns from the ceilometer are put into three different bins. When there’s a “cloud hit,” the system identifies a well-defined and sharp signature pattern that you’d expect with the sensor striking the cloud base. Essentially this means most of the hits are aggregated around a particular height above the ground. Such a sharp signature is then incorporated into the 30-minute sky cover and cloud height harmonic average, and a new observation is born.

On the other hand, a “no hit” is recorded when there isn’t an ample amount of backscatter received, usually because there are no clouds below 12,600 feet agl over the sensor. Note that the ASOS (and AWOS) is designed only to detect clouds below 12,600 feet above the ground, although a trained observer can and does report higher clouds. Lastly, if the backscatter does not provide that sharp signature around a particular height, an “unknown hit” is recorded. It is this unknown hit that leads us down the path to an indefinite ceiling or vertical visibility.

Haze, Mist, and Fog, Oh, My!

So, isn’t an indefinite ceiling the same thing as a ground fog event? Not necessarily. Stratus is the most common cloud associated with low ceilings and reduced visibility. Stratus clouds are composed of extremely small water droplets or ice crystals (during the cold season) suspended in the air and may be touching the surface, so to speak. An observer along a coastal region or on the side of a mountain would likely just call this plain old fog. This is certainly understandable, since we grew up calling this kind of situation foggy.

Fog, however, is thought to be more of an obstruction to visibility from a surface observing standpoint. To understand the recording of obscurations, here’s how the ASOS automatically determines what to report. Once each minute, the obscuration algorithm checks the reported visibility. When the visibility drops below 7 sm, the current dew point depression (temperature-dew point spread) is checked to distinguish between fog (FG), mist (BR), and haze (HZ). If the dew point depression is less than or equal to 4 degrees Fahrenheit (~2 degrees Celsius), then FG or BR will be reported. Visibility will then be used to further differentiate between FG and BR.

Whenever the visibility is below five-eighth sm, FG is reported regardless of the “cloud” that produces it. So fog isn’t really about a cloud or ceiling as much as it is about visibility. Therefore, stratus and fog frequently exist together. In many cases, there is no real line of distinction between the fog and stratus; rather, one gradually merges into the other. Flight visibility may approach zero when flying in stratus clouds. Stratus over land tends to be lowest during night and early morning, dissipating by late morning or early afternoon. Low stratus clouds often occur when moist air mixes with a colder air mass or in any situation where temperature-dewpoint spread is small.

• READ MORE: Decoding the Weather

Moisture-Rich Environment

Essentially, an indefinite ceiling means there is something obscuring your view of the cloud base. When you look up, you won’t be able to see a well-defined cloud base like you would on a day where the sky isn’t obscured. According to the ASOS User’s Guide, “these ‘unknown hits’ are primarily caused by precipitation and fog that mask the base of the clouds.” The laser beam bounces off moisture at various heights, making it impossible to process this as a definite cloud hit. Instead, the ASOS identifies these unknown hits as a vertical visibility abbreviated as “VV” in the resulting routine or special observation.

Given the broad moisture field near the surface that scatters the laser beam signal, indefinite ceilings are guaranteed to be paired with low visibility situations. You are not going to see a surface visibility of 10 miles paired with a VV of 200 feet. Usually this means a low or very low IFR flight category anytime there’s an indefinite ceiling. Also keep in mind that an indefinite ceiling in a terminal forecast will result in a low visibility forecast.

In general, the higher the vertical visibility, the better the surface visibility. Therefore, a vertical visibility of 200 feet (VV002) is usually met with a visibility of one-half sm. Furthermore, a vertical visibility of 700 feet (VV007) will likely be associated with a visibility between 1 and 2 sm. While rare, you may even see a fairly high vertical visibility over 1,000 feet (e.g., VV012). In this case, the surface visibility may be over 3 sm. The really bad stuff, however, occurs with a visibility of one quarter sm (or even “M1/4 SM” denoting less than that) and a vertical visibility of zero feet (VV000) as illustrated in the image below for Bradford Regional Airport. This very low indefinite ceiling is not all that common unless you are stationed on the summit of Mount Washington in New Hampshire, where this low vertical visibility happens quite often throughout the year. It also occurs fairly often at airports along West Coast regions of the U.S., especially during their “May gray” or “June gloom” time frame.

As mentioned earlier, fog and precipitation are the two primary reasons the base of the cloud deck is obscured. Therefore, it’s common to see vertical visibility reported when light rain, drizzle, or even snow is falling from the cloud base.

Precipitation or not, it’s generally rare to see a single station reporting an indefinite ceiling. Most of the time, you will see indefinite ceiling reports embedded in a widespread area of low or very low IFR conditions, especially at coastal airports. Although airports such as Nantucket Memorial Airport (KACK) in Massachusetts can be reporting a low indefinite ceiling, at stations farther inland near Cape Cod the sky can be clear or nearly so.

It’s important to note that conditions producing an indefinite ceiling often take longer to improve. Normally there will be a transition from an indefinite to definite ceiling once the moisture begins to mix out with the help of the sun. However, the visibility may still be quite low for the next few hours. Keep this in mind when flight planning to an airport reporting an indefinite ceiling.

Operational Significance

From a practical standpoint, you should treat an observation or forecast for a vertical visibility the same as you’d treat a definite ceiling. Given the nature of conditions that produce an indefinite ceiling, you can expect a longer transition as you depart into such a ceiling under IFR. It’s easy to get spatial disorientation because of the gradual change.

An indefinite ceiling restricts the pilot’s flight (air-to-ground) visibility. Therefore, an instrument approach may be a bit more challenging even after you drop below the reported ceiling height because of the reduced visibility. Most importantly, a circle-to-land approach with an indefinite ceiling will make it quite difficult to keep the runway in sight, especially at night. And, as a final consideration, with an indefinite ceiling, don’t be surprised to see runway visual range also pop up in the observation for airports with such equipment.

This feature first appeared in the October 2023/Issue 942 of FLYING’s print edition.

The post Here’s the Lowdown on ‘Vertical Visibility’ appeared first on FLYING Magazine.

For the past week much of California has been experiencing heavy rain and snowfall described by meteorologists as an “atmospheric river.” The heavy precipitation has been blamed for urban flooding, landslides, and at least three deaths. It has also led to numerous flight delays and cancellations.

According to the MiseryMap as of Friday, there were noticeable delays at both San Francisco International (KSFO) and Los Angeles International (KLAX) airports to Seattle and Denver.

Ground travel  has also been impacted as the California Department of Transportation reports landslides on highways and power companies report thousands of people without electricity as a result of downed power lines and felled trees because of the saturated soil. In addition, law enforcement officials in parts of Southern California have reported downed trees that appeared to have been caught in a tornado.

There is so much rain that officials in Southern California issued a warning about excessive rainfall. According to data from the National Weather Service, record amounts of rain fell in a single day in multiple locations, including at several airports.

Van Nuys Airport (KVNY) has received a total of 9 inches and KLAX 5.68 inches, including 2.37 inches in one day. Other one-day, record-breaking totals include Long Beach Airport (KLGB) with 2.31 inches and Burbank’s Bob Hope Airport (KBUR) with 2.08 inches.

Earlier in the week, Santa Barbara Airport (KSBC) was closed to all traffic because of flooding. Travelers were urged to contact their airlines directly for more information.

In the San Francisco Bay Area, some residents have been without power for more than five days and are bracing for another strong storm set to move in over the weekend, bringing with it more heavy rain and wind gusts of up to 60 mph.

This story is evolving and will be updated as appropriate.

The post California Airports Reeling from Heavy Rain appeared first on FLYING Magazine.

Question: Is flying through snow an icing hazard?

Answer: There is an opinion in the aviation community that flying through snow is not only an icing hazard but also against FAA regulations for pilots in aircraft without a certified ice protection system. Keep in mind that each weather system is unique, and there are many exceptions to the general view presented here.

Let’s discuss some of the many factors associated with flying through snow.

Snow falling out of the base of a cloud means there are fairly deep, saturated conditions aloft. To produce snow typically requires that the cloud top temperature (CTT) be sufficiently cold. That usually means a CTT of minus-12 degrees Celsius or colder—the colder the air, the more likely the precipitation type is snow. In this situation, ice crystals can dominate any supercooled liquid water in the cloud and lead to the development of snowflakes in the cloud aloft. If you are flying through snow below the cloud base, does that imply icing conditions exist? Just to be clear, this is not a discussion of flying in the clouds producing the snow but below the cloud base. 

Snow is considered visible moisture. It can be mixed with other precipitation types that may include rain, freezing rain, or ice pellets. In general, snow falling from the base of a cloud doesn’t represent a significant airframe icing hazard unless it is mixed with other types of precipitation such as freezing rain. It can be an issue with induction icing but not airframe icing. In the unlikely case that snow does adhere to the airframe, an exit plan should be executed. 

• READ MORE: What Is Mixed Icing?

Outside of a mixed-precipitation scenario, snow is usually classified as wet or dry. Wet snow occurs when the static air temperature is at or above 0 degrees Celsius. That is, the snow falls into an atmosphere warmer than freezing and begins a melting process. Although liquid water doesn’t necessarily freeze at a temperature below 0 degrees Celsius, snow must begin to melt at a temperature warmer than that. If the temperature is warm enough, it will completely melt the snowflake into a raindrop before reaching the surface. You may have experienced this while driving in your car. You’ll see the wet snowflake splat on your windshield and quickly melt. Wet snow can begin to accumulate on grassy surfaces or other vegetation but usually melts quickly on other surfaces.

Moreover, because you are flying at an airspeed where kinetic heating occurs on the leading edge, even at a static air temperature of 0 degrees Celsius, snow will typically not accrete on the leading edges of the wings and horizontal stabilizer as a result of this kinetic heating driven by adiabatic compression. This is typically referred to as ram air rise. And certainly, with a static air temperature above 0 degrees Celsius, ice is very unlikely to accrete with the additional ram air temperature rise. In fact, even at a static air temperature of minus-1 or minus-2 degrees Celsius, accreting ice is difficult at best. Once the static air temperature gets colder than minus-3 C, then you are no longer dealing with wet snow since no melting is occurring.   

Certainly, wet snow can be problematic while taxiing. Or, if you pull your airplane out of a warm hangar, even dry snow will melt and begin to collect on some surfaces and may accumulate over time. It is recommended that you never depart with any of the aircraft surfaces contaminated, including wings and the horizontal stabilizer. Doing so may cause the aircraft not to develop the lift necessary to take off and climb, creating a risk of impact with terrain. 

Another metric to use is the Current Icing Product (CIP) found on the Aviation Weather Center website. CIP utilizes a recent three-hour forecast from the Rapid Refresh (RAP) model for parameters such as temperature, moisture aloft, supercooled liquid water content, and other useful model data. This is mainly to “seed” the forecast for these items, given that observational data is rather sparse throughout the atmosphere for these important parameters. Nevertheless, it combines this with surface observations, ground-based radar, pilot weather reports, satellite imagery, and lightning to produce an hourly analysis of icing probability, icing severity, and supercooled large-drop icing potential from the surface through 30,000 feet.  

CIP looks for information about the presence or absence of six precipitation types—freezing rain (FZRA), freezing drizzle (FZDZ), ice pellets (PL), rain (RA), drizzle (DZ), and snow (SN). A report of any of the first five means that altitudes below cloud base need to be considered for possible icing and SLD, because subfreezing liquid precipitation may be present. However, in an observation in which only snow is reported at the surface, ice crystals are clearly present beneath and within the lowest cloud layer, and those are not considered an icing threat, especially below the lowest cloud base. 

For example, if an airport is reporting an overcast sky at 2,500 feet and only snow is being reported, the CIP algorithm will remove any possible occurrence of icing from the cloud base down to the surface, regardless of what other sources may say. This is because snow not mixed with other precipitation types, such as freezing rain, is not seen as an icing hazard…even wet snow.  

Is it legal to fly through snow in an aircraft without a certified ice protection system? First you may want to read this letter from the FAA’s Office of the Chief Counsel. An excerpt  states: 

The formation of structural icing requires two elements: 1) the presence of visible moisture, and 2) an aircraft surface temperature at or below zero degrees Celsius. The FAA does not necessarily consider the mere presence of clouds (which may only contain ice crystals) or other forms of visible moisture at temperatures at or below freezing to be conducive to the formation of known ice or to constitute known icing conditions. There are many variables that influence whether ice will actually be detected or observed, or will form on and adhere to an aircraft. The size of the water droplets, shape of the airfoil, and the speed of the aircraft, among other factors, can make a critical difference in the initiation and growth of structural ice.

Yes, snow is definitely visible moisture, but will it adhere to the airframe? Dry snow is not going to adhere to the airframe while in flight. Wet snow, as mentioned above, is more of an induction icing or ground icing concern than airframe icing while in flight. 

Sometimes it’s not about airframe or induction icing. Flying through falling snow can also be very disorienting at times, especially when the snowfall is moderate or greater, or you are flying at night. It will often lower flight visibility to 3 sm or less and can make runways extremely slick. Landing while it is snowing on a snow-covered runway can lead to a flare at an altitude higher than normal, making for a hard landing.      

One last point. Often when snow falls into a fairly deep, dry layer below the cloud base, it can sublimate on its way down. This usually occurs with the onset of precipitation as a weather system approaches. Evaporation and sublimation are both cooling processes, and they will lower the temperature of the dryer air. An atmosphere that is a few degrees above freezing can lead to melting wet snow, and this process can quickly move the temperatures to below freezing, allowing for snow to reach the surface instead of melting.

The post Is Flying Through Snow an Icing Hazard? appeared first on FLYING Magazine.

Question: What is mixed icing?

Answer: To answer that question, let’s look at the three icing types that pilots are asked to report. These include rime, clear, and mixed. What icing type accretes on your airframe depends on many environmental factors. Let’s briefly discuss each of these factors as it relates to the type of icing.  

Rime icing is a rough, milky, or opaque ice that is typically formed by the rapid freezing of supercooled liquid water drops onto the airframe. The rapid freezing helps to allow air to be trapped inside the ice, making it appear whiter. If you grew up with an old freezer that required regular defrosting, that ice buildup is similar to the appearance of rime ice. In other words, it has a frosty appearance.

First and foremost, rime icing is most common when temperatures are relatively cold, allowing the freezing process to occur rapidly. Small drop environments also tend to help with rapid freezing as do low liquid water contents. One place that this tends to occur is in stratiform clouds because the drops tend to be small and the water content tends to be low. But even in these clouds, if the temperatures are close enough to freezing, or the water content or drop size increases a bit, the icing could become more mixed or even clear. 

Keep in mind that the colder it gets, the more likely it is that any ice accreted would be rime. Remember, these are just tendencies. There’s no guarantee of what kind of ice you’ll get based solely on temperature or the type of cloud. There are many factors that come into play that are sometimes difficult to quantify or predict.

Clear icing is a glossy or translucent ice formed by the relatively slow freezing of supercooled liquid water drops. This tends to occur in clouds with a high liquid water content and larger drop sizes with rapid accretion like you might find in a cumuliform-type cloud. Clear ice also tends to occur in the warmer subfreezing temperature range and in  a large drop environment produced by freezing rain and freezing drizzle.

Moreover, larger drops such as those found in freezing rain and drizzle tend to exist at warmer subfreezing temperatures. Studies have shown that freezing rain only exists down to about minus 12 degrees Celsius, while freezing drizzle can exist at much colder temperatures, sometimes as cold as minus 21 degrees Celsius. However, the frequency of freezing rain and drizzle drops off sharply with decreasing temperature. In-flight studies suggest that the colder the situation, the smaller the drops tend to be outside of convective activity. 

Mixed icing can be thought of as a transition between clear and rime icing. Another way to get mixed icing is to fly through multiple icing situations, some that produce ice that’s more on the rime end of the spectrum and others that produce ice that’s more on the clear end of the spectrum. The overlap of these types can give it a mixed look. For mixed icing to build on its own, it comes down to that energy balance. If you’re somewhere between the energy balances that form rime and clear ice, then the resulting icing can have characteristics of both types.

Perhaps the most common occurrence of accreting mixed icing is during a climb or descent. For example, as the aircraft climbs, it may initially be accreting clear ice because of warmer temperatures. But as the temperatures get colder in the climb, rime ice begins to accrete over the clear ice, creating that mixed look. Essentially the altitude change takes the aircraft through multiple icing environments over a given time. Pilots will report this as mixed icing.

As shown in the pie chart above, rime is definitely the most common type reported. The reason rime ice is so common is because it occurs over a broad range of environmental conditions. Clear ice, on the other hand, occurs over a much narrower range of conditions, so it is observed less frequently. Mixed ice can be thought of as a transition from rime to clear ice, also occurring over a narrow range of conditions, so it is also relatively uncommon.  

Pilots are encouraged to report the type of icing they encounter. So, understanding where these types accumulate on the airframe can help you provide the best report. Rime icing tends to be closer to the immediate leading edges, thanks to the rapid freezing process. It’s the reason most ice protection systems are located on the leading edges of the airframe, where rime ice generally accumulates. Clear ice tends to extend farther back on the wing’s surface and sometimes well beyond the leading edge. If the aircraft has boots, then any ice accretion behind the protected surface can continue to accumulate, creating an ice ridging situation. Ice protection systems that employ TKS fluid do a wonderful job limiting runback ice since the fluid is dispersed well behind the TKS panels. These are generalities that hold true a lot of the time, but there are exceptions, especially as the complexity of the icing environment increases.

Making a good pilot weather report (PIREP) as it relates to airframe ice is critical. Reporting ice during a climb or descent without reporting the altitudes that you witnessed ice accretion is not helpful. Instead, provide the icing type along with the altitude range where icing was experienced. And be prepared to also provide the outside air temperature since it’s required anytime you report ice. It’s important to be sure you are reporting the static or outside air temperature and not the total air temperature—sometimes called the “ram” air temperature.  

The PIREP shown from the EZWxBrief progressive web app (ezwxbrief.com) is an example of a good icing report. The pilot of a Cessna 208 reported light, clear rime ice with a temperature of minus-10 degrees Celsius. But the remark in the report is the key. The remark (RMK) of “LGT CLEAR ICING 051-031” suggests that ice accretion was witnessed between 5,100 and 3,100 feet msl. About the only improvement I can suggest is to mention whether the icing was in the cloud or below the cloud within precipitation. 

The post What Is Mixed Icing? appeared first on FLYING Magazine.

The U.S. Air Force’s new Boeing T-7A Red Hawk trainer is undergoing climate chamber testing in Florida, the service announced Tuesday.

A series of testing is underway at the McKinley Climatic Lab at Eglin Air Force Base, Florida, to verify T-7A system functionality during periods of extreme temperatures. During the tests, performance of the T-7’s propulsion, hydraulic, fuel, electrical, secondary power, and overall operations will be evaluated in conditions ranging from minus-25 degrees to 100 degrees Fahrenheit.

• READ MORE: First Air Force Pilot Flies T-7A Red Hawk

The Red Hawk is set to replace the 1960s-era T-38 trainer for Air Force fighter and bomber pilot flight training. Its iconic red-tail livery honors the Tuskegee Airmen of World War II, the U.S. Army Air Forces’ first Black aviation unit. 

Last month, the advanced trainer made its first cross-country flight to Edwards Air Force Base in California for flight testing.

• READ MORE: Air Force’s T-7A Trainer to Begin Next Phase of Flight Testing

“The Red Hawk must withstand a range of environments from sitting on the ground in the Texas heat to flying at altitude,” Troy Hoeger, Air Force Life Cycle Management Center’s T-7A chief developmental tester, said in a statement. “The climatic lab helps us do this in a deliberate and methodical way and will give us confidence that our new aircraft meets requirements.” 

The $9.2 billion Air Force program includes the purchase of 351 Boeing T-7A jets, 46 simulators, and support.

The post Air Force’s T-7 Red Hawk Undergoes New Round of Testing appeared first on FLYING Magazine.

As a flight instructor and former National Weather Service (NWS) research meteorologist, I’ve accepted that pilots like to rag on meteorologists for issuing bad forecasts. Even so, once I got the full backstory behind the pilot’s dissent for a majority of these cases, there was nothing inherently wrong with the forecast; it was how the pilot was trying to use the forecast that was often problematic. This is not to imply that meteorologists are always accurate in every forecast they issue, but pilots tend not to appreciate the hard limitations these forecasts demand.

A terminal aerodrome forecast, simply known as a TAF, is perhaps the most difficult forecast any meteorologist will ever make. Think about the challenge these forecasters face. A TAF is essentially an hour-by-hour forecast for conditions significant to aviation at an airport over the next 24 or 30 hours. This includes a forecast for details such as wind speed and direction, cloud coverage, ceiling height, prevailing visibility, and precipitation type.

When you think of a TAF, size matters. This forecast is difficult because of the relatively small diameter of the area they are attempting to cover. The U.S. definition of a terminal area is the region within five statute miles of the center of the airport’s runway complex. Thus, meteorologists refer to a TAF as a “point forecast,” and it’s critical to understand its limitations and how they affect the forecasts general aviation pilots ultimately use every day.

The Terminal Area

A five statute mile area is a tiny region to get all forecast elements right over a given period. In fact, the terminal area is often smaller than the resolution of the forecast guidance they are using to issue the TAF. It’s like placing a coin on a sidewalk and asking someone at the top of a five-story building to identify if the coin is a nickel, dime, or quarter using their naked eyes.

Here’s a way to visualize why it’s so hard to issue these forecasts. Let’s pretend for a moment that you are the forecaster and someone asks, “What are the chances there will be a thunderstorm reported somewhere in the conterminous U.S. in the month of July?” Certainly, there are a lot of thunderstorms in July, and the conterminous U.S. encompasses a huge area. Your forecast would likely be that there’s a 100 percent chance. And you would be 100 percent correct.

That was an easy forecast, and you didn’t even need a meteorology degree to get it right. Now, how about a slightly different question? What is the chance of a thunderstorm reported sometime during the month of July in the state of Oklahoma? Given a month is a long period and Oklahoma is a state with lots of thunderstorms during the summer, again, I’d bet your answer would be that there’s a 100 percent chance. Now, how about the chance of a thunderstorm being reported on July 14 at the Oklahoma City airport at 8 a.m.? Well, once again, there’s a pretty easy answer; you’d likely say it’s a zero percent chance.

When you narrow down the time and the location, you can see the swing from a near guarantee at 100 percent to a near guarantee at zero percent. Forecasting for a small five statute mile area is incredibly difficult, if not fundamentally impossible at times, but meteorologists at the local weather forecast offices are asked to carry out the impossible every day. They need to determine if that coin is a nickel, dime, or quarter.

There’s no doubt that TAFs are used by all pilots because of the significant detail they provide. Everyone from general aviation pilots to commercial air carriers utilize TAFs to anticipate weather conditions in the airport terminal area. Without question, TAF content can have a strong impact on fuel loads, the need for alternates, and other operational aspects because of their stringent regulatory nature.

Scheduling TAFs

Each weather forecast office in the conterminous U.S. is typically responsible for issuing a TAF for up to ten airports within its region of coverage called a county warning area or CWA. For example, the Greenville-Spartanburg forecast office in Greer, South Carolina, is responsible for preparing TAFs for six local terminal areas, including the Charlotte Douglas International Airport (KCLT).

It’s important that the TAFs are prepared and issued by local forecasters instead of forecasters sitting in some Washington, D.C., office. They often consider sub-synoptic local effects, and they are tuned into the local weather patterns since they deal with them every day. The difference between a low IFR ceiling and a clear sky can be just a matter of 10 miles at times.

Therefore, the size of the terminal area is a point (pun intended) that should not be overlooked. The TAF may or may not always be representative of an area or zone forecast. Additionally, locally derived forecast rules and outside pressure from the FAA or even the airlines can cause the TAF to be quite different than an area forecast.

Scheduled TAFs are issued four times daily (every six hours) at 00Z, 06Z, 12Z, and 18Z. In most circumstances, the TAF is transmitted between 20 minutes and 40 minutes prior to these times. Moreover, for high-impact airports such as Atlanta, Chicago and New York, TAFs may be routinely issued every three or even two hours. For now, those off-schedule issuances will still be released as amendments. So, if you see an amended forecast in these regions, it may not be because of a poorly aligned forecast with respect to the weather—it may be a new and improved forecast.

Precipitation events, especially thunderstorms, give meteorologists the most trouble. Forecasting convection in the terminal area is all about quantifying the uncertainty of the event. Even in reasonably dynamic situations with traveling weather systems, meteorologists can find it challenging to predict when convection will impact the terminal area over the forecast period.

Dealing with Uncertainty

Unfortunately, forecasters do not have a convenient way in a TAF to quantify their uncertainty. In the public forecast, you’ll see something like “a 30 percent chance of thunderstorms.”

Sure, forecasters can throw in a PROB30 forecast group into a TAF, but by NWS directives, PROB30 groups are not allowed to exist in the first nine hours of the forecast period. By the way, the NWS only uses PROB30, although you may see PROB40 in international TAFs or TAFs issued by the military. So, what can a forecaster do when there’s a chance of thunderstorms in the public forecast, but the uncertainty is high? In most cases, the forecaster will leave out any mention of thunderstorms given that it is just too uncertain and the likelihood is small that a thunderstorm will roll through that tiny forecast region. Forecasters are also pressured by the airlines to avoid placing thunderstorms in a TAF in these situations. A forecast for thunder may require filing an alternate, and the need to take on more fuel.

Perhaps in this uncertain situation, these are just the scattered variety of afternoon pulse-type thunderstorms. In this case, the forecaster has two possible solutions, neither of which will appear in your aviation textbook or ground school. First, they can add rain showers (SHRA) or showers in the vicinity (VCSH)

instead of thunderstorms. Showery precipitation is inherently a convective process. It’s not unusual to see forecasters include one of these two precipitation forecasts into the TAF when the uncertainty of thunderstorms is high. Essentially it becomes a placeholder for thunderstorms. When conditions eventually begin to evolve and it becomes clear thunderstorms will impact the terminal area, the forecaster will likely amend the TAF to replace SHRA or VCSH with TSRA (rain and thunderstorms within the terminal area).

Area Forecast Discussions

Second, forecasters may often explain their reasoning in the area forecast discussion or AFD. No, it’s not a discussion about the aviation area forecast that was retired in 2018. Instead, it’s a discussion about the weather expected in the local county warning area (CWA) for that weather forecast office. Every AFD contains an aviation section that discusses the TAFs for airports within that CWA. It is in the AFD that a forecaster can explain, contemplate, brood over, or even complain about why they didn’t include a forecast for thunderstorms, fog, or freezing rain.

In fact, most forecasters will do a pretty good job trying to quantify their uncertainty. In the case of thunderstorms, you may see words in the AFD like “including light rain showers to cover the unlikely threat of thunderstorms.” The AFD isn’t something you’d get in a standard briefing, but it certainly should be part of your preflight brief. I’ve always said that if you are not reading the AFDs, you are missing half the forecast.

You can find the full AFD for each county warning area by visiting the weather.gov website. If you visit weather.gov, in the upper-left corner, type in a location such as an airport, city and state, or Zip code, and you will be presented with a forecast that includes a link on that page labeled “Forecast Discussion” that is valid for that town or airport. That link will contain the entire discussion that includes the aviation section. The AFD is also included in some of the heavyweight aviation apps or using my EZWxBrief progressive web app.

Local Knowledge

So, the next time you pore over the TAFs along your route, remember these two points. First, never assume the weather forecast at one airport applies to a nearby airport. On some occasions when the weather is homogeneous across a region, it very well may be that a TAF is representative of the weather at airports close by. Forecasters have local knowledge and often make forecasts that take into consideration how terrain or the previous day’s weather can impact the weather at any particular airport.

Second, TAFs are not an area or zone forecast and should never be used as such. It’s often easy to look at all of the TAFs along your route and make a hasty decision. Just because the three or four TAFs along your proposed route do not mention thunderstorms doesn’t mean you won’t encounter them during cruise. Use TAFs for what they are intended to show. Therefore, if you have an emergency and need to land, knowing the potential weather at those airports along your route is important. TAFs can tell you if they are likely to be good alternates if you need one.

Lastly, keep in mind that a precipitation forecast in a TAF defines the type of precipitation expected to reach the surface. For example, a forecast for –RA (light rain) or –DZ (light drizzle) doesn’t imply there’s no chance of running into FZRA (freezing rain) or FZDZ (freezing drizzle). The precipitation forecast is based on what’s expected at the surface. If the temperature is forecast to be a degree or two above freezing at the surface, you will see a forecast for rain (or drizzle), but you may find that just 500 feet above the surface, there’s a nasty freezing rain (or freezing drizzle) event waiting for you.

The post The Point Forecast Sheds New Light on TAFs appeared first on FLYING Magazine.

Question: Is freezing fog considered “known icing conditions”?

Answer: As we start to move into the cold season over the next couple of months, you may begin to see freezing fog (FZFG) appear in a surface observation (METAR) or  terminal aerodrome forecast (TAF). So, let’s get ahead of the game and discuss some high-level details of what freezing fog is all about and whether or not it constitutes known icing conditions. 

In simple terms, freezing fog is nothing more than an obstruction to ground visibility.  When surface observing equipment such an ASOS measures the visibility to be less than 7 sm, a reason for what’s causing the decrease in surface visibility must also be included. Besides freezing fog, other common obstructions to visibility include HZ for haze, BR for mist and FG for fog. 

Haze or mist are the most common obstructions to visibility. They are added to the report when the surface visibility is less than 7 sm but greater than one-half of a statute mile. Once the visibility drops to one-half of a statute mile or less, fog becomes the dominant obstruction to visibility and FG is added to the report. In this case, when the temperature is also at or below 0 degrees Celsius, then freezing fog becomes an obstruction to visibility and FZFG is added to the report. 

The important thing to understand is that the software employed by the ASOS makes this determination solely by using the reported surface visibility and temperature independent of any ice accretion or if clouds are actually touching the surface. At times, airports with a trained human observer can override this as was done in this surface observation for Spokane, Washington (KGEG).  

KGEG 271353Z 19008KT 1/4SM -SN BR FEW001 OVC003 M03/M04 A2993   

    RMK AO2 SLP157 SFC VIS 2 VIS NW-N 1 P0000 T10331039

In this case, the reported visibility is one-quarter of statute mile and the temperature is minus-3 degrees Celsius. Both of these conditions meet the criteria for freezing fog. Therefore, if this were an automated report, the obstruction to visibility would have included freezing fog, or FZFG. However, notice in the remarks section, the observer notes that the surface visibility is 2 sm, and visibility to the northwest and north is 1 sm. Effectively the trained observer felt the obstruction was more representative of mist (BR) and not freezing fog.  

Is freezing fog considered known icing conditions? The short answer is no. According to the National Weather Service (NWS) directives, freezing fog is “consisting predominantly of water droplets at temperatures less than or equal to 0 degrees Celsius whether or not the fog is expected to deposit rime ice.” Once again, fog or freezing fog is an obstruction to visibility simply based on the measured surface visibility and temperature. Nevertheless, in a dense radiation fog event, ice may indeed accrete on the airframe while taxiing to depart.    

Similar to surface observations, freezing fog can also appear in a TAF. The same general rules apply. When a forecaster expects the visibility will be at or below one-half of a statute mile and the temperature will be at or below 0 degrees Celsius, they will ordinarily forecast FZFG. Based on the same NWS directives, freezing fog in a terminal forecast by itself is not a forecast for known icing conditions.

It is true that fog consists predominantly of water droplets when the temperature is warmer than 0 degrees Celsius. But to know if freezing fog is an icing hazard is a bit more complex and depends on many factors—not all of them are specifically discussed here. 

Freezing fog is primarily a ground icing issue, not an in-flight icing concern. The two environments have a great deal of differences and may depend where you are departing. For example, if you are flying out of Grand Forks, North Dakota (KGFK), which is landlocked, your chances of getting any significant liquid water content is pretty small, especially for radiation-type fog events that occur at warmer, subfreezing temperatures. In fact, the forecasters at the Grand Forks weather office don’t issue many TAFs with FZFG for that reason. The meteorologist in charge at the NWS Forecast Office in Grand Forks has mentioned to me,“…In our temperature regimes and winter air mass scenarios, we typically don’t have that high of true liquid water droplet concentrations but probably more suspended ice crystals…so we may get a bit of glaze but not a true rime-icing scenario.” 

• READ MORE: Fog: the Malignant Weather Ninja

Many years ago, I asked Dr. Marcia Politovich, an aviation icing expert and a deputy director at the University Corporation for Atmospheric Research in Colorado, weighed in on the topic. 

“It’s not likely that a surface temperature of minus-3 degrees Celsius or above could support mostly or only ice crystals, but history matters,” Politovich said. “Where the crystals came from is important [maybe they formed aloft in very cold air and are falling slowly through a warmer layer near the ground]. The local ice nucleus source might not be as important as what would be in the air, carried from some other location. Also cloud nuclei [for water drops] would also be sourced locally, so if the air is very clean, it’d be hard to produce anything very near the surface.”

Therefore, in a much colder temperature regime, it’s unlikely you’ll experience much in the way of rime since the fog will consist predominantly of ice crystals. If you are departing out of an airport near a large body of water or when the soil has been moistened after a precipitation event (other than snow), it is quite common to have some ice deposit onto the prop and other surfaces of the aircraft when the static air temperature is between 0 degrees and minus-10 degrees Celsius.  

However, if there’s no ice accreted after you finish your preflight and/or if the static air temperature is below minus-10 degrees Celsius, then the likelihood of ice rime on the airframe is minimal while the aircraft is waiting on the ramp or taxiing. Lastly, the most important rule is to never take off if the surfaces of your aircraft are contaminated with ice.

The post Is Freezing Fog Considered ‘Known Icing Conditions’? appeared first on FLYING Magazine.

Every pilot certificate and every rating you pursue will have a weather learning component to it. One of the most important concepts you cover is about clouds—how they are classified and formed and what their appearance means in terms of atmospheric stability.

I live in the Pacific Northwest, where fog—the lowest of the low clouds—is a nearly daily occurrence, especially in the fall and winter. I live close to the water, and on some days it never lifts. Other days, we get a few hours of flyable sunshine and visibility, and we watch the temperature and dewpoint spread very carefully because fog can sneak up on you ninja-like. And if you are not instrument rated and in an instrument-capable aircraft, instrument current, instrument proficient, and prepared to “go on the gauges,” you may have a really bad day. Know your enemy, as my father used to say.

• READ MORE: When Smoke Gets In Your Skies

What Is Fog?

Per the FAA’s Instrument Flying Handbook, fog is defined as a low cloud, which has its base within 50 feet of the ground, reducing visibility to less than five-eights sm. In order for fog to form, three basic conditions must be met:

• There needs to be condensation nuclei, such as smoke particles, salt, dust, pollen, etc., for the moisture to condense upon. In the Pacific Northwest, we have this in the form of salt from the ocean and smoke from all the wood stoves.

• There must be high water content and a low temperature/dew point spread. Dew point is the temperature the air must be cooled to in order to become saturated. When the air is cooled or moisture is added to it and the temperature and dew point are within 4 degrees Fahrenheit/2 degrees Celsius of each other, fog is likely, as it forms when the temperature and the dew point converge. As the day heats up, the temperature dew point diverges, and the fog ‘burns off.’ In the evening, the process reverses. In  the afternoon, especially in winter, the process reverses usually around 3 p.m. Keep this in mind when you head out on late afternoon flights.

• Fog forms when light surface winds are present as they cause surface friction to create an eddy, causing more air to contact the ground

Fog is basically a cloud at the surface, but like other clouds, there are varieties, and each has certain characteristics. For example, some need wind to form.

To recall the types of fog, use the acronym SURAPIF (Steam, Upslope, Radiation, Advection, Precipitation, Ice, Freezing).

Steam Fog

Steam fog, sometimes known as “sea smoke,” forms when cooler air moves over slightly warmer water. Steam fog is usually not very thick and needs wind to form. It is associated with a shallow layer of unstable air, so you can expect convective turbulence flying through it.

Upslope Fog

Upslope fog forms as moist, stable air is pushed up a hill or other sloping land mass. As the air moves up, it cools, and when the temperature and dew point converge, there is fog. Mountain fog is sometimes mistaken for smoke, which is how the Great Smoky Mountains in North Carolina and Tennessee get their name. Per the Aviation Weather Handbook, this type of fog is most commonly observed in the autumn and spring months and is the densest around sunrise when surface temperatures are often at their lowest.

Radiation Fog

Radiation fog, also known as “ground fog,” forms over low-lying, flat surfaces on clear, calm, humid nights, especially over a wet surface like ground after rain. As the surface cools, the adjacent air also cools to its dew point and fog forms. Radiation fog can vary in depth from a few feet to about 1,000 feet and usually remains in place.

A subset of radiation fog is valley fog, which, as the name suggests, forms in lower-lying areas. It is very thick and is sometimes referred to as “tule fog.” It can form when the air along ridgetops cools after sunset. As the air becomes more dense and heavy, it flows down the slope to the valley floor, where it continues to cool and becomes saturated to form fog.

Radiation and valley fog can drop visibility to near zero and make any kind of transportation hazardous because you can’t see in front of you and lack any depth perception. You may not even want to taxi in that kind of fog. Radiation fog is often a factor in chain-reaction accidents on highways in the winter months.

Advection Fog

Advection fog occurs when a low layer of warm, moist air moves over a cooler surface. This is very common along the West Coast in winter. Advection fog requires wind to form, and an increase in wind speed can make it thicken. It is also tenacious, moving over water and then inland, then back over water for days or even weeks at a time. The horizontal movement of advection fog helps distinguish it from radiation fog.

Precipitation Fog

Precipitation fog forms when rain evaporates as it falls through cold air. When the precipitation stops, the fog disappears. You can notice this when the objects at the end of the runway disappear under fog as it rains then reappear when the rain ends.

Ice Fog

Ice fog forms in polar and arctic regions—and other cold weather locations—when the temperature is minus-10 degrees or below, and the air is too cold for the air to contain supercooled water droplets, so it forms tiny ice crystals.

Freezing Fog

Freezing fog occurs when water droplets freeze on contact to a surface that is below 32 degrees. This means anything the freezing fog touches will become coated with ice—including all aircraft. Sometimes you can watch it form on cold mornings. As the fog rolls in, the aircraft on the ramp will slowly see their windows turn opaque, and their surfaces will appear to sparkle. This process is different from frost forming, which usually involves sublimation.

Respect the Fog

Even with an instrument certificate and an airplane loaded with the latest in technology, fog can quickly become too thick to operate in and destroy visibility. This is why instrument approaches have weather minimums in the form of ceiling and visibility printed on them. Respect the metrics, as sadly every year there are pilots who attempt to land in weather below the minimums and don’t live to tell the story because they misjudged their altitude or distance from terrain because of fog.

The post Fog: the Malignant Weather Ninja appeared first on FLYING Magazine.

“If you don’t know something, don’t try to b.s. the examiner. Look it up.”

Do you remember getting this admonishment before your private pilot check ride? I do. It meant picking up the appropriate text—more often than not the FAR/AIM—and going to the back of the book to the index. The index was pretty easy to use as the words are arranged alphabetically. Sometimes it took a few tries to find what you were looking for—would the airspeed indicator be listed under airspeed or required instruments for VFR flight?—but with a little patience you could find it and follow the page number to the appropriate section.

As we have progressed to a digital society, fewer and fewer learners and even instructors know how to use the index in a paper book. In an e-book, it’s easy. An algorithm does the work for you.

In a paper book, it is a little more involved, starting with the introduction of the user and the concept of an index. I have added this to the list of things I teach my clients, and occasionally, my coworkers.

I use the paper version with learners that are tactile and kinetic and learn better by holding a book in their hands and turning the pages. When the new versions come out, we make a game of making tabs to make it easier to find certain things—such as FAR 61.87 requirements for solo. You can buy the books pre-tabbed, but many learners find the task of making tabs and placing them in the book aids in the learning process.

That is not to say I don’t also use the digital version: I do. Frankly, it doesn’t matter if you get the information from paper or digitally. The important thing is you know where to find it.

Analog Clock

Can you tell time from an analog clock? The ability to read one is becoming a lost skill. I recently met a freshly retired high school teacher who told me that most of the kids in her classes cannot tell time from an analog clock. “They use their phones,” she said.

This is concerning, because in aviation the analog clock is used as a reference to determine position, i.e. “traffic at your 3 o’clock.” It is getting more difficult to convey this concept to learners, so much so that one CFI I know has taken to having learners set their smartwatches to an analog display or obtain a cheap analog watch to help them learn the directions that correspond to the numbers.

Aviation Weather.gov Gets a Makeover

Flight instructors have learning curves too. As I write this, I am learning how to use the redesigned version of NOAA’s weather page, AviationWeather.gov. I have relied on the webpage for years for supplemental weather information.

• READ MORE: NOAA Changing Weather Site

For years, my day began by tapping on the icon on my smartphone, putting in “@WA” and clicking on TAFs and METARs, and in an instant the weather from every available airport in the state of Washington was displayed. That told me if the day was going to be spent in the air or on the ground. When it was an air day, Leidos briefings followed before each flight and ForeFlight followed us into the cockpit. Weather is a hobby of mine, going back to my fledgling television career where I figured if I was going to report the weather, I needed to know something about it.

The new AviationWeather.gov site offers a great deal of information on climate, severe weather, fisheries, etc. I can imagine it being a good resource for studying these topics. But it’s an awful lot to wade through for a supplemental weather briefing.

Learning Takes Place

I watched the video tutorials. Because the new one has so much information, you need to go on a scavenger hunt to find what you want. The TAFs and METARs are buried under layers labeled “Tools and Resources.” A few times, I got the NOAA version of the “spinning beach ball of death” as I searched for things. There are more colored graphics on the new site, and if that is how you like your weather information presented, you’re going to be a happy camper. If you prefer black and white text, the graphics are a lot of noise. The Terminal Weather Dashboard is confusing and hard to read, and although the redesign was supposed to make it easier to use on smartphones, I have not found this to be so.

I am not the only person having a challenge. The day the site went live hundreds of pilots, including many instructors, voiced their displeasure. A colleague noted that the weather is presented in the decoded form and predicted that this would “throw a monkey wrench into the knowledge tests” as learners are asked to decode weather reports.

There is no such thing as an FAA-approved weather briefing, but some products are better than others. I am partial to those that require a discreet login and can be customized so that a few keystrokes take you to the place you need to be. Some pilots find the app-based subscription products not worth the investment when they only fly a few times a year. Same goes for the budget-minded learner who’d rather spend the money on flight lessons.

I am still compelled to show the learners how to use 1800WXBRIEF.com to get a briefing and file flight plans since it does not require a paid subscription.

When was the last time you called 1-800-WX-BRIEF for a weather briefing? With the development of online applications, calling for weather has fallen out of favor. But until that option goes away, I want my learners to know how to get a weather briefing by phone, just in case their iPad, tablet or smartphone fails or goes missing. If the internet crashes or cell towers are jammed, you’ll know how to use pay phones as well—granted, the most challenging aspect is likely finding one. You may end up borrowing the phone of the FBO in some cases.

Don’t be intimidated. Follow the voice prompts and when you get the person, explain you are a student pilot, and they will walk you through the process. It is not that difficult, and you can check that off your “have to try it at least once” list, treating it like it is the aviation version of going to the L.L. Bean store in Maine and getting your picture taken in front of the giant boot. If you have the opportunity, make it happen. 

The post Teaching Analog Skills in a Digital World appeared first on FLYING Magazine.

Question: The EFB I use has an option for MOS forecasts… What is that and can that be used legally for planning a flight?

Answer: MOS stands for model output statistics and is pronounced “moss.” MOS has been around since the 1960s and was originally developed to provide aviation meteorologists with guidance to produce useful forecasts to pilots. But over the last decade, MOS has been making its way into the aviator’s toolkit and is offered by a couple of the heavyweight electronic flight bag (EFB) apps. 

So, what does MOS offer? Crazy as it may seem, most pilots really want to know what’s happening at an airport from a weather perspective. Before they depart, they’d like to know what the ceiling or visibility will be like when they reach their destination. Will they get that visual approach or will they need to prepare to fly an instrument approach? Or perhaps they want to find an airport with favorable winds to practice some crosswind landings. 

There’s nothing special about these requirements, however. One nice aspect about MOS is that it’s available for more than 2,100 civilian and military airports throughout the U.S. and its territories. At the moment, the National Weather Service (NWS) only issues a terminal aerodrome forecast (TAF) for 700 airports in this same region. So, if your departure, destination, or alternate airport does not have a TAF, MOS provides some useful guidance about the expected meteorological conditions significant to aviation at those airports at the time of your departure or arrival. 

Here’s the technical part. Most weather prediction models that you often hear about on the local news, such as the American or European model, don’t automatically produce a point forecast for a specific town or airport for various sensible weather elements, such as ceiling height, visibility, and surface wind. This is where MOS shines. 

MOS combines this “raw” model forecast with geoclimatic data in an attempt to improve upon it using a statistical method. It relates observed weather elements (decades of past observations) to appropriate variables (predictors) via a statistical approach. Because it uses geoclimatic data, MOS is capable of accounting for local effects that cannot be resolved by these models alone. In other words, if the airport is in a valley or on a hilltop or next to a large body of water, MOS is able to account for that local topography. It’s a lot like the old local pilot who has been flying for 50 or more years that can tell you exactly what to expect on the final approach when the winds are coming off of the mountains west of the airport. 

The other important element is that MOS downscales the model data into weather elements important to aviation. This includes, but is not limited to, cloud coverage, ceiling height, prevailing visibility, wind speed and direction, precipitation type, and the probability of precipitation or thunderstorms. 

While MOS does an excellent job most of the time, remember it’s an automated forecast—there’s no human in the loop like a TAF. It should never be used as a wholesale replacement for a forecaster-issued TAF. So it should never be used to replace a TAF from a legal perspective. If the airport has a TAF, that forecast needs to be used to determine if an alternate is required and alternate minimums for instrument flight rules. MOS guidance is best used as a way to fill in the blanks when the official forecasts don’t provide the details necessary. 

• READ MORE: Navigating Smoke

Two of the three existing MOS forecasts are being retired in the next few years. However, the only version of MOS that has made its way into the FAA literature (see the Aviation Weather Handbook/FAA-H-8083-28) is called LAMP, which stands for localized aviation MOS program. It is issued hourly and is being fully supported by the NWS in the foreseeable future. Does this effectively mean that LAMP can be used to make operational decisions about a flight? I’ll let the legal scholars opine on that. Nevertheless, visit https://vlab.noaa.gov/web/mdl/lamp to view the suite of LAMP forecasts.  

MOS has some important limitations you should know about. It cannot forecast multiple cloud layers as you see in a TAF. Except for when the forecast is shown as clear, a single fixed cloud layer is the best MOS can do at this point, and it cannot tell the difference between a definite and indefinite ceiling. MOS also cannot directly forecast showers in the vicinity (VCSH) or fog in the vicinity (VCFG), nor can it forecast precipitation intensity or tell the difference between rain or drizzle. MOS is also unable to predict a variable wind.

The post What Is a MOS Forecast? appeared first on FLYING Magazine.

Question: On some NEXRAD images, I sometimes see a negative value for dBZ (decibel related to Z) for the reflectivity. How can these values be negative?

Answer: Of all of the weather guidance available to pilots prior to a flight, the images produced by the NWS WSR-88D NEXRAD Doppler radars are likely the most widely used in the U.S. These images have an extremely high glance value and are packed with important life-saving guidance assuming that a pilot knows how to interpret all the pretty colors.  

The colors you see on the Nexrad image displayed by your favorite website or heavyweight electronic flight bag (EFB) app depend on many factors. Unfortunately, accepted standards do not exist in the industry. Any private organization, vendor, or government agency is free to map the data (e.g., reflectivity) to colors of their choosing (although certified displays in the cockpit do have standards). Depending on their operational requirements, they may use three colors representing light, moderate, or heavy precipitation—or they are free to use 30 different colors.  So, it is important always to reference the scale that is normally located somewhere on the image or around the image border. For EFBs, that legend may be located on their interactive map, or you may have to look it up in their pilots guide. 

• READ MORE: Are Pilots Required to Call Flight Service for a Briefing Before Departure?

More importantly, there are many kinds of images and products that you may encounter. Therefore, knowing the kind of radar image you are viewing is also paramount. The image may display base reflectivity from a single NWS Nexrad radar that is in clear-air mode. Or it may be one of the volume products such as composite reflectivity or echo top heights. Another possibility is that the image may represent a radar mosaic that has combined the base reflectivity or composite reflectivity data from multiple Nexrad sites into a regional or national image.

• READ MORE: Why Are Some Airport Buildings Painted in a Checkerboard Pattern?

While forecasters at the various NWS local weather forecast offices (WFOs) do have real-time access to all of the data, the “raw” data that is generated by the WSR-88D Nexrad Doppler radars is not distributed directly to other government and private organizations in real time. Therefore, a Nexrad Information Dissemination Service (NIDS) has been established that includes only a subset of the entire WSR-88D base and derived products for use by external users. Below is the RPG console that you’ll find at every WFO that manages a WSR-88D Nexrad Doppler radar.

One of the most ubiquitous products is called base reflectivity. Note that the term “base” does not mean “lowest” as most pilots are taught or assume. It comes from the term “base data” since every elevation scan has a base reflectivity product (note in the image above that says “Base Data Display”). How you interpret the base reflectivity image will depend on the mode of the radar. In most cases, the base reflectivity will be the lowest elevation scan on various websites and apps since it better approximates the precipitation that is falling from the base of the cloud.     

The WSR-88D radar operates in one of two modes: precipitation and clear air. The main difference between the two is that clear-air mode offers the advantage of greater sensitivity because of a slower antenna rotation rate, which allows more energy to be returned back to the radar. However, clear-air mode takes twice as long to generate a product so it suffers from temporal resolution, but is able to detect smaller objects in the atmosphere such as light snow or drizzle.   

In either mode, the radar sends out a known pulse of energy in the microwave band (a wavelength of 10 cm to 11 cm). Some of this energy strikes airborne objects referred to as hydrometeors. This includes rain, snow, hail, dust, birds, insects, etc. and the power returned is referred to as the reflectivity parameter or Z. In basic terms, Z is the density of water drops (measured in millimeters raised to the sixth power) per cubic meter of air. As you might expect, there is a very wide range of possible Z values. Converting Z to dBZ (decibels of Z) makes that range smaller and easier to use.

When the radar is in precipitation mode, the range of dBZ values displayed can be as low as 5 to a maximum of 75, whereas clear-air mode offers a range from -28 to +28. Negative dBZ values can occur in clear-air mode because dBZ is a logarithmic function. So, an increase of only 3 dBZ actually represents a doubling of power returned. Anytime Z is less than 1 mm⁶/m³, dBZ becomes negative because of the nature of logarithms. Negative dBZs are only found when the radar is in clear-air mode such as shown above. This radar image shows light snow falling around the Bismarck, North Dakota, area. Given that light snow is falling, the operator at the NWS set the radar to its most sensitive mode, namely, clear-air mode. Notice the negative dBZ values in the dark taupe color. If the radar were in precipitation mode, the amount of coverage would be limited to the baby blue areas. 

A negative dBZ means that the radar is detecting very small hydrometeors. As mentioned above, this is a great way for forecasters to detect very dry light snow or drizzle which have lower reflectivity values. One of the disadvantages of clear-air mode is that any dBZ value under 5 typically gets filtered by the datalink weather. The Nexrad clear-air mode image above shows a rather wide area of light precipitation around the Bismarck radar site that represents light snow in this case. However, the SiriusXM weather image shown below only includes the returns that are greater than 5 dBZ. The areas shown in the taupe color in the Nexrad image have been effectively filtered out of the SiriusXM-delivered product due to their lower dBZ values.     

• READ MORE: Can I Fly VFR in Smoke?

Do you have a question about aviation that’s been bugging you? Ask us anything you’ve ever wanted to know about aviation. Our experts in general aviation, flight training, aircraft, avionics, and more may attempt to answer your question in a future article.

The post How Can dBZ Values Be Negative? appeared first on FLYING Magazine.

Question: Am I required to call flight service to get a briefing before I depart?

Answer: The short answer is no. The regulations do not specifically state that you must call Lockheed Martin Flight Service (LMFS) (e.g., 800-WX-BRIEF) to get a briefing. FAR 91.103 (a) simply states, in part:

91.103 Preflight action.

Each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight. This information must include—

(a) For a flight under IFR or a flight not in the vicinity of an airport, weather reports and forecasts, fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays of which the pilot in command has been advised by ATC.

• READ MORE: Why Are Some Airport Buildings Painted in a Checkerboard Pattern?

Certainly, a phone call on a recorded line to Flight Service (now known as Leidos) will fulfill most of these requirements. Briefers can provide the adverse weather along your proposed route of flight and assist you with identifying important NOTAMs and TFRs that may be relevant. You still must check many other aspects of the flight, such as takeoff and landing distances as well as weight and balance. But from a weather perspective, can you skip the call to Leidos and roll your own “weather” briefing and be perfectly legal?

Yes, you can, but here are the caveats. The Aeronautical Information Manual (AIM) and advisory circulars such as Aviation Weather Services, AC 00-45H, Change 2, provide you with guidance on how to get a good preflight briefing. These documents mention making the call to 800-WX-BRIEF as a legitimate source. While these documents are not regulatory, if you decide to roll your own briefing and something bad happens during your flight, you will likely need to show the FAA how you briefed yourself for the flight. If you can’t or your explanation isn’t satisfactory, the FAA will likely cite this as being “careless or reckless” under FAR 91.13 since it handed you the proper recipe for a briefing in these nonregulatory documents that clearly state it is wise to make that phone call.

Nevertheless, the FAA is making a reasonable attempt to recognize that more and more pilots are briefing on their own and not making that phone call. In the revision memorandum in AC 00-45H, Change 2 (November 2016) it states:

The experience of listening to a weather briefing over a phone while trying to write down pertinent weather information becomes less tolerable when the reports are easily obtainable on a home computer, tablet computer, or even a smartphone. To see weather along your route using a graphic of plotted weather reports combined with radar and satellite is preferable to trying to mentally visualize a picture from verbalized reports. Although most of the traditional weather products, which rolled off the teletype and facsimile machines decades ago, are still available, some are being phased out by the National Weather Service (NWS) in favor of new, Web-based weather information.

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• READ MORE: How Many Hours in What Aircraft Are Needed Before Commercial Check Ride?

Moreover, a letter dated June 28, 2017, from the assistant chief counsel of the FAA stated in a legal interpretation that, “The PIC’s failure to contact LMFS prior to a flight would not be a violation of 91.103.”

How about using one of the heavyweight electronic flight bag (EFB) apps to get your briefing? Yes, some of the heavyweight apps also provide a way to get a briefing that is logged and recorded that will fulfill the regulatory requirements in part. In fact, the FAA stated in the same 2017 opinion letter that “similarly, a PIC’s reliance on only an EFB would not be a per se violation of 91.103.” The letter also cautioned that “we note, however, that there may be limitations and quality assurance issues in connection with the information available through certain EFB products that may affect compliance with 91.103 and necessitate further information gathering regarding the flight.”

• READ MORE: Can I Fly VFR in Smoke?

Do you have a question about aviation that’s been bugging you? Ask us anything you’ve ever wanted to know about aviation. Our experts in general aviation, flight training, aircraft, avionics, and more may attempt to answer your question in a future article.

The post Are Pilots Required to Call Flight Service for a Briefing Before Departure? appeared first on FLYING Magazine.

Since writing about the world of home flight simulators for FLYING, I have largely focused on the “new” Microsoft Flight Simulator 2020 (MSFS2020). There are many reasons for this as this latest entry into the most famous flight sim of all time looks and feels incredible. The visuals are certainly the stuff imaginations are made of, especially for those of us over 40 who began our sim careers flying a Cessna 182RG where advanced scenery was a few sticks and lines to look like Chicago. 

Now that we have become accustomed to the visuals and feel of MSFS2020 and comfortable with all the available add-ons and updates to improve the experience, it could be easy to forget the “other” sim, X-Plane.

I have been an X-Plane customer and user since it was invented and have had phone calls and even met with Austin Meyer at a sim conference years ago. X-Plane 11 (XP11) was the only sim I used a few years back after the original MSFS X was discontinued and further development seemed over. 

• READ MORE: A Better Virtual Flight Deck

My love of XP11 didn’t transfer easily to XP12. Graphical glitches, texture shimmers, performance issues, incompatibility of add-on aircraft previously purchased, etc., made for a frustrating time. 

Up until just two weeks ago, I resigned to sticking with XP11. Then, suddenly, a new update to XP12 beta was released. The sky coloring, lighting, cloudscapes, and weather modeling all came together. 

Previously purchased XP11 aircraft all started getting updates to make them fully XP12 compliant. The performance issues I had in earlier updates in XP12 seemed to have gone away as well. Even the most complex jetliners now performed as well in XP12 as in XP11, all the while looking superior in the new lighting and weather. On my modest laptop with most detail sliders three-fourths of the way up and running in 2K native resolution, I often see frame rates over 50 frames per second. The in-game weather has not affected this, which is a real shock.

I recently started experimenting with live weather as it was occurring near my home. Flying various aircraft in XP12 at that exact moment has given me an appreciation of how accurate the live weather is, along with its stunning graphic depiction.

Flying the Toliss A319 from New York to southern New England provided some excitement as I headed toward a squall line approaching my home, Worcester Regional Airport (KORH) in Massachusetts. The clouds were bubbling up in the right places. 

Trying to beat an advancing line of heavy convection, you can see the lower buildups over 10,000 feet here, but much higher in the distance, corresponding with the bigger storms and tops. The accuracy and feeling of blasting through these tops is fabulous and is accompanied by clouds, bursts of loud rain, or ice, depending on the temperature. 

I could not get to my destination of KORH because it was below minimums, and I made a missed approach. As I proceeded eastward to my alternate airport—Laurence G. Hanscom Field Airport (KBED) in Bedford, Massachusetts—I broke out of the advancing weather to see the overhang of thunderstorms advancing my way. I used a ForeFlight app on an iPad to accompany my XP flights. 

Here, we see the overhanging anvil clouds coming out of the top of the lower convection zone. This is a realistic meteorological phenomenon that pilots see up high. Some lower-level haze and fogging is also seen. This effect is incredible and very accurate. It is probably the best depiction of weather I have ever seen in a sim. 

Using the same Airbus Corporate Jet ACJ319 in the Caribbean with convective weather produced visuals such as soaked runways, engine blowback, mist, tire spray, and reflectivity. It is all amazing.

The sim showed heavy rain being wiped away. The runway water model features performance degradation, as well as visuals. The rain impact, and especially the sound of the heavy rain, is better than the MSFS2020 version, which is quiet and weak.

The default heavy A330 circumnavigates around a big cumulonimbus cloud at altitude. 

Runway reverser action in the sim includes moisture fogging on the engine inlet. 

Flying across the U.S. and approaching the monsoon convection over New Mexico, Arizona, and Utah, I can parallel and see the entire event 100 miles away. This visual candy is so true to real life, as I often see at FL400 in the bizjet I fly for work. 

The fictional Columbia Airlines Flight 409 heavy makes her way westward. Look at that gorgeous shine on metallic surfaces and sunlight reflection with the new XP12 lighting effects.

Gazing southwards, you can see the weather systems with cirrus clouds now included. The far-away depiction of weather is my favorite new effect for realism and a sense of upcoming trouble. It looks no different than in real life.

Columbia 409, after a squall as the sunshine evaporates the puddles that formed during the rain. 

While X-Plane 12 makes weather enticing to fly in, I find the active, or live thermals are still not up to snuff compared to MSFS2020. Their new thermal model really knocks you around, and operates using live weather and time of day. 

I hope X-Plane will improve the thermal simulation, as currently, sunny days with live weather don’t bounce you around. However, as always, you can simulate this stuff easily by manually editing the live weather downloaded, introducing turbulence up to cloud lines, and playing with the thermal values in the weather menu. This helps the choppiness in GA aircraft down low. But as for the convection-related clouds and weather, X-Plane is superior. If you’re not careful, bad things will happen to you in and around thunderstorms. It’s enough to tempt even the most safety-minded sim pilots to act like fools just to see how scary it can get.

The post Weather Wonders of X-Plane 12 appeared first on FLYING Magazine.

Hundreds of flights in and out of Florida have been canceled as the Sunshine State prepares for Hurricane Idalia to make landfall Wednesday. 

On Tuesday morning, the storm was gaining strength as it moved over the state’s Gulf coast. It was expected to make landfall as a Category 3 storm.

“On the forecast track, the center of Idalia is forecast to move over the eastern Gulf of Mexico [Tuesday], reach the Gulf coast of Florida within the Hurricane warning area on Wednesday, and move close to the Carolina coastline on Thursday,” the National Hurricane Center said in a statement Tuesday morning.

According to the National Oceanic and Atmospheric Administration (NOAA), “there is a danger of life-threatening storm surge inundation along portions of the Florida Gulf coast, including the Tampa Bay and Big Bend region of Florida which may see water as high as 8 to 12 feet above ground level.

Tuesday morning, the FAA said it was rerouting aircraft, closing Gulf routes, and also considering pausing flights at Palm Beach International (KBPI), Miami International (KMIA), and Fort Lauderdale International (KFLL) airports.

The FAA is re-routing aircraft and closing Gulf routes as Hurricane #Idalia is expected to hit the Florida region Wednesday morning. We may pause flights in and out of @flyPBI, @iflymia and @FLLFlyer to keep you safe. Monitor https://t.co/smgdqJNBiL. #FAAWeatherSquad pic.twitter.com/xkwSDMsuGy

— The FAA (@FAANews) August 29, 2023

As of Monday night, approximately 500 flights in and out of Tampa International Airport (KTPA) were preemptively canceled, CNN reported. By Tuesday, cancellations continued at several airports, resulting in a domino effect across the nation’s air travel grid. More cancellations are possible.

According to the storm models under review by NOAA, the agency that tracks hurricanes, Category 3 storms carry winds greater than 80 mph. 

As of 11 a.m. EDT, a look at the TAFs for the state shows multiple airports with strong winds from the south with gusts forecast to approach 50 mph.

Time is running out to prepare for Idalia! Follow the urgent advice from local officials. This hurricane could very well join the extensive list of storms starting with the letter I that have been especially destructive. pic.twitter.com/GjryWUCnl1

— NWS Director (@NWSDirector) August 29, 2023

The post Flights Scrapped as Florida Braces for Hurricane Idalia appeared first on FLYING Magazine.

“Goodness, look at the smoke!” said one visitor at EAA AirVenture in Oshkosh, Wisconsin, on Monday evening. 

The sunset was blood red, discolored by the smoke coming down from Canadian wildfires. The smoke did not clear by Tuesday morning, as the sun rose looking like an orange in the smoke and haze.

• READ MORE: Navigating Smoke

The smoke was not the only weather challenge pilots faced on their way into the mega air show. Lines of thunderstorms forced many pilots to divert en route.

By Monday, the wildfire smoke was playing sort of a cat-and-mouse game with aviators. In the morning it appeared to be no more than a light layer of haze. By evening, however, the setting sun glowed red in the west and the Air Quality Index reached 167, which is regarded as unhealthy. At outdoor parties and campsites you could feel the smoke stinging your eyes.

As the sun rose Tuesday, the haze still hung in the sky. But, as all pilots know, the weather can change, and filing IFR to handle a smoke event has become part of their training.

• READ MORE: Aviation Maintenance in a Time of Wildfires

The post Smoke Descends on Oshkosh appeared first on FLYING Magazine.

Textron Aviation, the manufacturers of the Beechcraft King Air, will be sending five of the turboprops to Saudi Arabia in support of a weather modification mission.

The specially modified aircraft will be used for cloud seeding.

Cloud seeding involves the deliberate introduction of various substances, often dry ice or silver iodide, that acts as condensation nuclei in an attempt to induce precipitation.

According to Textron, the company was awarded the contract by AvMet International LLC based in Fargo, North Dakota, for one Beechcraft King Air 360CHW and four Beechcraft King Air 260.

• We Fly: Beechcraft King Air 360

AvMet and its partners Weather Modification International (WMI) and Fargo Jet Center (FJC) will equip the aircraft with a cloud water inertial probe (CWIP), data logger with aircraft tracking, and cloud seeding equipment. 

“We’re honored AvMet has chosen a fleet of Beechcraft King Air aircraft to support the Kingdom of Saudi Arabia’s National Center for Meteorology cloud seeding program,” said Bob Gibbs, vice president, special mission sales for Textron Aviation. “The King Air continues to be selected for a wide range of special mission roles around the world due to the aircraft’s capabilities and reliability.”   

The post Saudi Arabia Selects King Airs for Weather Mission appeared first on FLYING Magazine.

Question: Does an automated surface observation system (ASOS) have a built-in lightning detection system? Without an observer, how does it know to add a thunderstorm (TS), thunderstorms in the vicinity (VCTS), or tell you about lightning in the distance?

Answer: Some ASOS sites do have a single-site lightning sensor in the array. If there isn’t a lightning sensor at the site, it is still possible for the ASOS to report lightning. For FAA-sponsored ASOS sites without a lightning sensor, lightning data is made available to the ASOS through the automated lightning detection and ranging system (ALDARS), which is a ground-based lightning detection system. ALDARS is not coresident with the sensor and sends the data to the ASOS. Here’s how it all works at a simplified level.

• READ MORE: Why Do Runways Get Renumbered?

Without a human observer logged in to the ASOS terminal, it will format a METAR or SPECI (special observation) for lightning in one of three ways: TS, VCTS, or lightning in the distance.

1. If the cloud-to-ground lightning strike is detected within 5 miles of the ASOS (usually within the airport’s terminal area), the ASOS will make a special observation (SPECI) and carry “TS” in the body of the special observation in the present weather field. If precipitation, such as rain or freezing rain, is also detected by the sensor array, the observation will include RA (or perhaps freezing rain or drizzle) along with the precipitation intensity (e.g., +TSRA for heavy rain and thunderstorms). “TS” will continue to be carried in the present weather field in subsequent observations until no cloud-to-ground lightning strikes are observed for a 15-minute period within that 5-mile radius. At that time, the ASOS will make a second SPECI observation and officially end the thunderstorm (removes the TS from the METAR).

• READ MORE: Is It Possible to Legally Fly a Cessna 150 as an LSA?

2. If the cloud-to-ground lightning strike is between 5 miles and 10 miles of the ASOS (the vicinity of the terminal area), the ASOS will make a SPECI observation and carry “VCTS” in the body of the observation in the present weather field. “VCTS” will continue to be carried in the present weather field in subsequent METAR observations until no cloud-to-ground lightning strikes are observed for a 15-minute period in the vicinity. At that time, the ASOS will make a SPECI and officially end the report of thunderstorms in the airport’s vicinity.

3. Separate from above, or independently, if the cloud-to-ground lightning strike is between 10 miles and 30 miles of the ASOS, the ASOS will carry a “LTG DSNT XX” remark, indicating distant lightning, with “XX” being the direction of the lightning in octants. This will be appended as appropriate on all SPECI and/or METAR observations.

For stations with a human observer logged into the ASOS terminal, the observation can be overridden or augmented to include adding remarks, such as FRQ LTGICCG OHD TS OHD MOV NE, which translates to frequent (FRQ) lightning (LGT) in clouds (IC) and cloud-to-ground (CG) overhead (OHD) with thunderstorms (TS) overhead (OHD) and moving (MOV) to the northeast (NE). Lastly, in the remarks of the METAR or SPECI, you will see a group that provides the exact time the thunderstorm begins and ends, such as TSB0159E30, which means the thunderstorm began (TSB) at 0159Z and ended (E) at 30 minutes after the next hour or 0230Z.

Do you have a question about aviation that’s been bugging you? Ask us anything you’ve ever wanted to know about aviation. Our experts in general aviation, flight training, aircraft, avionics, and more may attempt to answer your question in a future article.

The post Does ASOS Have a Built-in Lightning Detection? appeared first on FLYING Magazine.

Ever since the day I received my private pilot certificate, my instructor has been on my case to train for an instrument rating. If you are serious about traveling in a small aircraft, he always says, you need to be instrument rated.

For years I did not think much about his advice because most of my flying consisted of short hops in fair weather with no pressing need to reach a particular destination. After we bought our own aircraft late last year, though, I quickly came to understand the appeal of instrument flying. Now there are places my family and I want to go, and the airplane is the ideal transport—as long as the clouds are not too low, the morning fog has lifted, and the smoke from recent wildfires in Canada is not too thick.

• READ MORE: Your Ideal Aircraft Belongs on ATC Radar

There are so many things that can scrub a VFR mission, especially as we begin to fly longer distances. When we were taking the club’s Cessna 172 on 50 nm jaunts for breakfast or lunch, we were not too worried about the weather shifting as we traveled. A lot can change over 300 to 500 nm, though, and I have had to postpone numerous trips lately because of forbidding weather at our destination or at some point along the way.

Being able to fly through a low overcast would solve many of my problems, and my airplane is particularly well-equipped for instrument flight. I am beginning to feel like a slacker for not at least trying to match my aircraft’s capabilities.

• READ MORE: Taking the Dogs on Vacation in Your Ideal Aircraft

When my wife and I bought our Commander 114B, we agreed I would begin instrument training as soon as possible, so, yes, I have already waited too long. Still, there is a positive result from my delay. In our nearly seven months of ownership, I have seen firsthand how easily weather can affect our flying plans. I often wind up driving for 10 hours, looking at my kids’ disappointed faces in the rearview mirror, when the airplane could have made the trip in two hours while giving us a sweeping view of traffic-choked highways.

Over time I have transitioned from dreading instrument training to wanting it badly. It helps to know what you are missing. Clearly there will still be delays and cancellations even after I am rated to fly “in the soup,” but they will happen far less often. My family and I will have more freedom to make our own schedules and stretch out toward more distant destinations.

I recently recalled a scene from Mad Men in which main character Don Draper and pilot colleague Ted Chaough fly to a critical meeting in bad weather with Ted at the controls of his own airplane. The usually cool Don is clearly rattled by the experience while Ted pushes on through dark clouds and heavy rain. This was a high point for Ted, who confidently ended the scene with priceless comments about instrument flying.
For me there were few likable characters in Mad Men, but for just that moment I wanted to be Ted.

The post Instrument Rating Can Expand Your Travel Horizons appeared first on FLYING Magazine.

Boston, 8 a.m.: I button my uniform jacket, don a neon safety vest, and step outside the jet bridge into a roaring gale. Most captains do the walk around on the first officer’s flying legs at my airline, and it’s John’s turn to fly, so, per tradition, I brave the howling wind and pouring rain. By the time I reach the Boeing 737’s tail, I am soaked to the skin. I turn to inspect the tail skid and am nearly swept off my feet by a fierce gust that has every bit of 50 knots in it. I am reminded of the time I rode out Tropical Storm Isaias aboard Windbird. This day has the same evil intensity to it.

Twenty-four hours ago, I awoke to a much gentler morning, sun-kissed and caressed by the gentle trade winds of Aruba. This tropical layover was the main reason I specifically bid this four-day trip. It came at the price of a Boston-Detroit-Seattle last day, always a bit of a gamble in late December.

This Article First Appeared in FLYING Magazine

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This time it looks like I’ve lost the bet. I woke up fully expecting one or both of today’s flights to cancel. The news has been dominated by the massive weather system—a “bomb cyclone” named Winter Storm Elliott—that has impacted nearly the entire country. With Christmas a few days away, mass cancellation of jam-packed flights is a major story. My airline already canceled a significant portion of our schedule for the next two days, which isn’t entirely out of character. We have one of the lowest cancellation rates among U.S. airlines but, paradoxically, are fairly aggressive about canceling preemptively. The idea is that by canceling early and in a controlled, coherent manner, you can avoid operational meltdowns that leave crews stranded all across the system and unable to staff scheduled flights for days to come. But alas, it is not my lot to sit on the sidelines today. Instead, John and I are among those chosen to set out from coast to coast in truly execrable weather and attempt to operate a semblance of airline service. First, in Boston, we will battle heavy rain and winds gusting to 45 knots. Then, in Detroit, we face even higher winds, frigid temperatures, moderate snowfall, and blowing snow. Finally, back home in Seattle, freezing rain has turned the airport into a giant skating rink. I can’t remember the last time I’ve flown in such poor weather at three widely-spaced locations in a single day.

I return from the walkaround soaking wet. The flight attendants make sympathetic noises and hand me galley wipes to dry my hair. The flight plan is fairly straight-forward; our alternate doesn’t have much better weather than Detroit, but we’re loaded to the gills with gas, which puts warm fuzzies in my cold captain’s heart. Our turbulence forecast is suspiciously muted. I tell the flight attendants to stay seated until further notice and, preflight duties complete, wander back to first class to welcome the frequent fliers and explain just what we’ll be doing today. We have several million milers aboard, but everyone is wide-eyed and paying attention to every word. These people drove here in this weather—they know it’s terrible.

We push back and taxi out right on schedule, and the wind has obligingly eased by a few knots, the rain has slackened, and the sky is appreciably lighter. The airspeed bounces all over on the takeoff roll, but the predictive windshear alert system remains gratifyingly silent. I call rotate, and John skillfully eases the 168,000-pound machine into the air. The ride is every bit as rough as expected, but only for a few minutes. At 6,000 feet msl we unexpectedly blast out into brilliant sunshine and smooth air. In fact, it remains smooth all the way to Detroit, though we pass over places like Buffalo and Cleveland that are being absolutely walloped.

As we approach Detroit, the wind is still gusting to nearly 50 knots but only 20 degrees off of the crosswind runways, and the snowfall and blowing snow is moderate enough that the snow plows are easily keeping at least one runway open with good braking action reported. When we break out two miles from Runway 27R, a stark winterscape greets us. The snow streaks tearing across the runway make the crosswind appear fierce, but it’s actually pretty benign. John makes a great landing, and the braking is decent in patchy dry snow. There’s not much moving at the airport, and I am ultra-cautious while taxiing in. Many a crew has made a great landing in terrible conditions only to stick a wheel in a snowbank on their way to the gate. In our case, the main hazard seems to be snow plows that are amusingly oblivious to the presence of airplanes at a major airport.

There are no voicemails from crew scheduling when I turn on my phone, only incredulous texts from friends following my progress across the storm-wracked country. John and I hurry to the next jet. There must be plenty of flights operating because the terminal is bustling with passengers on the move, and a rather cheerful holiday mood prevails. I expected piles of stranded passengers with desperate snowpocalypse vibes.

In fact, all our connecting passengers show up on time, though we are delayed somewhat for bag loading thanks to the icy ramp. While we wait, crew scheduling calls my cell phone. In this case, it’s not to change our trip, only to offer me overtime flying for tomorrow, Christmas Eve. As it happens, one of the trips available has a single leg from Seattle to Minneapolis, which is exactly where I am attempting to travel on severely overbooked flights! I gladly accept a lucrative payday to upgrade from the cramped jumpseat to the more comfortable captain’s perch for my holiday journey.

There’s one remaining wrinkle: We have to deice, but it is so cold that Type IV anti-icing fluid has limited effectiveness, and we must depart less than 15 minutes after deicing, or else make a pre-takeoff visit to the cabin to inspect the wings more closely. In this case, we’re airborne and clawing our way into the maelstrom with a good two minutes to spare. Again, we find smooth air at altitude and have a much nicer flight than the en route weather might suggest. I think about guys like Ernie Gann and Bob Buck in the Douglas DC-3 days and what they would have gone through on a day like this. For that matter, I know there are still hardy freight dogs duking it out down in the weather in ancient Piper Navajos and Cessna 402s. I silently salute them.

The freezing rain in Seattle persists longer than forecast but tapers enough to allow two-runway operations by the time we arrive. Again we break out a couple hundred feet above minimums and are treated to the striking sight of an icebound SeaTac airport. Our runway has been deiced, however, and I manage to keep the pointy end forward. Our day ends with a 30-minute delay that is simultaneously maddening and amusing. Someone drove a lavatory servicing truck onto our parking spot and walked away with the keys, and nobody can find them. I barely suppress the urge to laugh out loud while explaining the situation to our long-suffering passengers.

One week later, I am writing this on a chartered catamaran swinging at anchor in Cane Garden Bay, Tortola. The stars are shining brilliantly in a clear sky, live music is floating from shore on a warm breeze, and waves lap softly on the hull. Winter Storm Elliott already seems like a long- faded dream, and I struggle to recall details. One mildly difficult day plying the nation’s skies in historically atrocious weather will go down as a minor footnote in a lifetime largely dedicated to flight. This is as it should be, a credit to a system that regularly makes the remarkable routine, safely stretching the boundaries of what man and machine are capable of.

This article was originally published in the March 2023 Issue 935 of  FLYING.

The post Anatomy of a Bomb Cyclone appeared first on FLYING Magazine.

Thunderstorm season is in full swing nationwide and around the globe. Nothing could strike more fear in an experienced pilot than accidentally straying into a monster storm. 

Yet every year we see news stories about airliners that have their noses punched in by hail or cockpit window layers shattered and cracked. In June 2009, Air France Flight 447, an A330, was destroyed during severe storms over the Atlantic after stalling and plummeting to the ocean. Faulty pitot units and inexperienced relief pilots at the controls were also considered factors in the incident, according to French civil aviation safety investigators.

Pilots can explore flying in thunderstorms in Microsoft Flight Simulator 2020 (MSFS), which offers convection realism.

• READ MORE: A Virtual, Wind-Battled Landing on a Mountaintop Runway

MSFS’ default weather does a pretty good job of interpolating where thunderstorms are located. For this example, I flew a morning trip from the Southern California/Los Angeles area over to the Palm Springs region as actual live thunderstorms were expanding. 

With ForeFlite running, I headed right for the convective area. My weapon of choice was the A319 corporate jet available from the sim marketplace online—the “Latin VFR” Airbus series, or LVFR.

Some run-back water effect was noted too, although it’s difficult to see in this screenshot. This was all very spot on and pretty realistic, but without any added turbulence. Autopilot was on, so the aircraft held steady.

Even though they were funny looking, I appreciated the fact that if you were to fly under them, you would definitely encounter rain in those precise areas.

In battling the live weather phenomenon, I had not seen any lighting at all. I am sure if it’s there, it would be hard to see during the daytime, just as in real life. 

MSFS includes a built-in powerful manual weather tool. Let’s build up our own convection, the stuff real photos are made out of. 

For this example, I started at Lake Tahoe Airport (KTVL) in South Lake Tahoe, California, up high in the Sierra Nevada Mountains. I am imitating realistic spring and summer storms forming over the high country with great visibility around the cells. 

I “stretched” the cloud bottoms and tops to realistic values around 5,000 feet AGL, with tops over 30,000 feet. I then moved the precipitation slider to near max rainfall rates of 1-plus inches per hour. The lightning slider went up to 88.53 percent. 

For this demo, I decided to “rent” a nearby Boeing Business Jet (BBJ) courtesy of PMDG Simulations.

One part really looks like a tornado, although I believe it’s a virga burst instead. I plunged under it in the thick of the rain. It was loud and clattering, but only for a few seconds, then we continued inbound to Truckee, California, a place I have flown a Falcon 2000 into in real life. It’s big enough to handle the BBJ. 

I also had a good visual on the runway, with the storm just off to the left, not quite blocking the final but almost to the centerline. 

I feel the visual quality of the skies can’t be beat in MSFS2020. The ability to manually produce the weather you’re looking for is easy and fun to tinker with. Moving cloud bases up or down, and stretching the tops and sliders for density, percent coverage, and lightning, provides endless possibilities for visual clarity and screenshot capturing. 

By using live weather, you’re pretty much guaranteed a realistic skyscape worldwide, with much being supplied via satellite and data updates in the real world from meteorological sources. It’s a true weather engine and simulation. But something more magical, more graphically enhancing results from manually adjusting the weather.

Some Tips

Be sure to use the “realistic turbulence” option selected via the in-game menus. Access this option by toggling to: ASSISTANCE OPTIONS/PILOTING/TURBULENCE to REALISTIC. Not doing this means the turbulence effects are far too muted. 

I also recommend the Honeycomb quality flight controls available from Sporty’s. FSRealistic is a must as well, a wonderful add-on of turbulence, head sway, and sound effects so necessary for immersion, no matter what you’re flying.

The post Simulating Thunderstorm Convection Craziness appeared first on FLYING Magazine.