“The Fall of Saigon: FedEx Aircraft Mechanic Reflects on Journey from War 40 Years Later” –An amazing story

This post is to honor someone who deserves to be recognized.  Sometimes the job of flying puts us in contact with amazing individuals.  I have been fortunate to meet quite a few in my lifetime and perhaps that will be a topic for another post.  This is a story of one of them. In August 2014 I carried a remarkable individual on my jumpseat.  He did not think his story impressive, but I strongly disagreed!  The very next day I sent the following email to one of the FedEx corporate communication people I had worked with on various projects:

“Let night I had the honor of carrying one of our mechanics, Mr. Do, on the jumpseat.  I invited him to ride up front, and during conversation I found out that he is quite a remarkable man.  It is a long story, but a few details  include that he was part of the South Vietnamese military, and after the U.S. pulled out and Saigon fell, he was captured, placed in a concentration camp, from which he eventually escaped, hid in the jungle, built a boat that he used to attempt to sail to Thailand, had their engine fail, drifted eventually into an oil platform, was rescued, and finally found himself in the U.S.  He has gone back to visit (since it opened), and that is quite a story as well.
I think that this would make a wonderful story, so I am sending his contact information to you in hopes you can either do it yourself or get it to the right person.”

I am honored to say that the story has now been published and you can click on the image below to view it and watch the video.  The URL is also listed below.

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http://about.van.fedex.com/blog/saigon-reflections-40-years-later/

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Posted in Safety

Indonesia AirAsia Flight 8501

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The Final Report of the Air Asia 8501 has been released.  This was a loss of control accident that does contain some lessons that are worthwhile sharing.

There had been an ongoing maintenance item that resulted the ECAM message of a AUTO FLT RUD TRV LIM SYS.  While it later turned out to be faulty wiring, their maintenance appeared to be treating it each time as a “one off” type of event rather than a repetitive maintenance item.  The maintenance procedures for a repetitive issue is often different than it would be for a single event.  Those of us who fly “electric jets” know that having a temporary “nuisance” type of alert is not rare, we call them “stray electrons” and are often the result of a slightly delayed power transfer or similar.  As a result they can often be fixed by just waiting a minute or, if that doesn’t work, the system can be rebooted.  These are issues common to any computer, whether it is your iPhone or an airplane.  Of course, in the case of our airplanes there are many systems that are inter-related and so a momentary glitch in one system can lead a second system to not start up correctly, etc.

The point here is that if it is a repetitive issue then it is likely a real fault of some sort and so when we write up a problem it is important to note that it is repetitive.  Now most company computer systems will also be tracking these but by putting the words “repeat item” in the maintenance logbook we can reduce the chance that it will be overlooked and proper procedures applied.

The next issue worthwhile looking at was what happened next.  Apparently the Captain on this flight had seen this maintenance item before and was watching while a mechanic “fixed” the alert by pulling some circuit breakers for the Flight Augmentation Computers (FAC).   During the accident flight the alert appeared several times.  Finally, after the fourth time, the Captain decided to pull those breakers inflight.  This is not a book procedure and resulted in the flight control system reverting to alternate law and the autopilot disengaging.  Procedures published for system problems are carefully thought out and absent an extreme emergency there is no reason to deviate from the published procedures.

The result of the alternate law resulted in the roll control on the control stick going from a rate command (you make an input and it sets a desired rate) to direct command (similar to a non-FBW airplane), while the pitch command remains in a mode pretty much similar to normal law without protections.  This means that in pitch the command on the stick is a “g” command, in which a neutral stick is commanding 1 g which will mean it will not change its vertical velocity, but unlike normal law it will not prevent the aircraft from stalling.

For reasons suspected to be distraction the first officer, who was flying, did not immediately notice that after autopilot disconnect the aircraft started to roll.  When he did recognize it he started to recover with both a roll and an aft stick movement and rolled from a 54 degree left bank to 9 degrees in under 2 seconds.  This might have created some other effects such as a vestibular illusion.  Following this, like AF 447 it appears that the first officer had a difficult time keeping the wings level.  This might seem surprising but remember that at FL 320 the aircraft was in a regime in terms of low air density that the first officer had likely never flown the aircraft, and, like AF 447, this was coupled with flying in a control law that was relatively unfamiliar.  In multiple previous events of this nature it resulted in some challenge for the pilot to control the roll.

The pull back is not explained but it may just be the nature of a rapid mechanical input where the hand moves to the right and back at the same time.  In any event, it resulted in the aircraft to rapidly pitch up.  From the reactions of the crew it appears that they were completely startled.  One wonders if they thought they had some secondary flight control issue going on, as it is clear that there was some confusion.  In any event, the aircraft progressed into a stall and aft stick position was maintained as the angle of attack increased to extreme values.  The communication between them was in English, which was neither of the pilots first language, and that might have contributed to the confusion.  For reasons unknown the Captain did not authoritively take command of the airplane and it appears that neither pilot recognized the stall.  For discussion on that, see my previous article.

It should also be noted that the aircraft descent rate became extreme and so was going to be much less than 1 g, let alone the higher g-demand that was being commanded by the aft stick pull.  The aircraft elevators will work to try to maintain the g-demand so even with the stick neutral if the aircraft is experiencing less than 1-g then the elevator will try to pitch to hold that 1-g.  Also, it should be noted that pushing forward on controls when at half a g or less requires overcoming a lot of natural human response.

One more note is that the Captain of this flight had considerable aerobatic and hands on flying as a military pilot so those that believe that more of that type of flying would prevent such accidents need to reconsider.  Clearly training is necessary and it is also clear that the industry has not addressed these issues satisfactorily at this time.

Posted in Safety

High Altitude Stalls – how well do you understand them?

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High Altitude Stalls – how well do you understand them?

By Captain Shem Malmquist

Acknowledgements

Credit for the impetus of this article must be given to my friend, aerodynamicist Clive Leyman, who initiated a discussion on these issues.  He provided the technical foundations, including correcting and clarifying portions of this article.  Portions of this article are based on a paper written by Clive Leyman, which have been revised as necessary for a more general pilot audience.

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Stalls and modern wing designs

There has been much written in the aftermath of the Air France 447 accident regarding aircraft stalls, pilot training and similar aspects.  In a previous article I outlined some of the cognitive aspects that were likely involved with the accident.  Many pilots have wondered why the Air France crew did not recognize the stall itself.  In this article I will explore some of the aerodynamic effects involved in high altitude stalls which can make the problem much more complex than many pilots might realize.

Modern airliner wings have been designed to minimize drag at the design cruising Mach number.  The aerodynamic design of the wing is based on the necessity to reduce wave drag and lift induced drag, and may be modified to reduce wing bending moments and weight.  These compromises mean that the way the air starts to separate as the angle of attack approaches the stall, and what forces are generated as it does so, may be significantly different than what most pilots are expecting.

As outlined in the figure below, on a typical airliner wing, the air will start to separate about 2/3rds of the way from the root to the tip.  It starts on the aft portion, so the forward section of the wing is still developing normal lift.  This results in a gentle pitch up.

stall progression

As the angle of attack is increased, the separation will move forward and across the wingspan, but these separations are still aft of the CG, so the aircraft will continue to have a gentle pitch up.  It is only after the inboard part of the wing stalls that there will be any pitch down at all, but in reality, this will likely just appear as a cessation of the pitch up.

Modern wings are designed to be “supercritical”, meaning that they are designed such that during normal cruise over a large part of the wing upper surface the airflow is supersonic, decelerating through a shock wave lying about two thirds to three quarters wing chord.  It is across this shock wave that the initial airflow separation will most likely begin, and that is near the trailing edge of the wing.  This will be perceptible as buffet.  Additionally, some of the lift is produced by positive pressure on the lower surface near the trailing edge.  This has the effect of increasing the lift on the wing with increased angle of attack for quite some time after the air flow on the upper surface as begun to deteriorate.

The experience most pilots had in primary training is a bit different.  In most trainer aircraft during the stall the airflow separation results in a loss of lift early in the process. As the airflow continues to deteriorate there comes a point where there is a fairly significant pitch downwards known as the “stall break” which is coupled with a simultaneous significant loss of lift.  The buffet is significant, and very obvious.

By contrast, the modern airliner wing will still see the lift increasing somewhat after the point that the pre-stall buffet has occurred.  This may, or may not coincide the the AoA at which the stall warning is triggered, with choice of that point left to the designer. Beyond that pre-stall buffet the lift goes on increasing very slowly (from the bottom surface flow), but the buffeting gets steadily worse.  At some point there is a change in the character of the buffet (magnitude and frequency) accompanied by a loss of lift. Taken together these may define “stall”, but it is difficult to identify the exact point without recourse to instrumentation. This is quite unlike anything met in training.

A word about high speed buffet

In addition to low speed buffet associated with the stall, many pilots also have read about, or been taught that the aircraft will experience a “high speed” buffet if they fly above the maximum mach speeds.  It is possible that some pilots might be concerned with lowering the nose as they might believe they are entering “coffin corner”, and lose control of the aircraft.  In reality, while this was a factor in early jet transports, it is no longer the case in modern designs due to aerodynamic improvements.  Any buffet experienced is almost certainly going to be due to pre-stall or stall buffet.

Stall identification

The JAR (see Annex) and FAR rules specify that; acceptable indications of a stall are –

  1. A nose-down pitch that cannot be readily arrested and which may be accompanied by a rolling motion which is not immediately controllable (provided that the rolling motion complies with JAR 25.203 (b) or (c) as appropriate; or
  2. Severe buffeting of a magnitude and severity that there is a strong and effective deterrent to further speed reduction; or
  3. In the case of dynamic stalls only, a significant roll into or out of the turn which is not immediately controllable.

As previously described on many modern wing designs the airflow separation will slowly spread outwards and forwards from the initial point.  This means that any changes in pitch or roll from the approaching stall can take place over a relatively long period of time (depending on the rate the AoA is increased), and there are no sudden indications.  This can somewhat mask the approaching stall, which can then only be identified through the severe buffeting criteria.  Further complicating this is that the buffeting could be mistaken for turbulence, as appeared to be the case in the other events described in my article on cognitive bias.  It is possible that mountain wave action or turbulence can induce a stall warning and possibly even pre-stall buffet at high altitude, although it is unlikely to cause an actual stall.

Air France 447

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AF 447 was in cruise flight at FL 350.  The Captain had chosen to take the “middle” nap, which is typical.  Unless unusually tired, most Captains will take a turn in the middle of the flight so they can be present for the more complex procedures during the first and last portions of the flight.  This can be altered, of course, depending on when they are tired, the Captain might choose the first or last period also.  The area of weather was still about 80 miles ahead of them when the Captain went back to take his nap.  Thunderstorms are typically somewhat numerous crossing the tropics, and it is probable that the aircraft radar was not depicting anything of significance that far out.

While some have questioned the decision of the Captain to take his rest at that time, it is not so surprising given the information present.  There was weather ahead, but it likely did not look particularly significant on the radar.  Again, there is a good chance it was not depicting much at all, as I have described in previous articles (here and here).  Further, it was likely that there would be more storms over the next several hours as they continued across the tropics.  Waiting was unlikely to improve things.  Personally, I would have chosen the first or second rest period just because I do not sleep well in turbulence and I have a bit more training with radar usage than many, but it is hard to second guess this Captain’s decision.  This left the First Officer in the right seat, as the flying pilot, and the relief First Officer in the left seat, as pilot monitoring.

When the aircraft encountered an area of high altitude ice crystals resulting in the loss of airspeed indications the autopilot and autothrust disconnected, unable to function without airspeed.  With the loss of airspeed came a multitude of various warnings as each system that utilized airspeed in some way indicated a problem.  The flight controls reverted to a degraded state where the pitch mode was still working normally in terms of response, but no longer had any of the stall protection features.  Meanwhile, the roll mode went to “direct law”. In “normal” operation the pilot would have become accustomed to the Airbus FBW mode where stick movement commands roll rate and centralizing the stick gives zero roll rate (holds the bank angle). However in direct law stick movement commands roll acceleration and centralizing the stick leaves the pilot with a residual roll rate. To cancel that one must apply opposite stick motion.  The A330 is also a surprisingly nimble airplane, and it is easy to over-control the roll when in direct law at altitude.

The pilot found himself flying an aircraft at altitude by hand.  Due to the lower dynamic pressure and higher true airspeeds for the same equivalent airspeed (EAS), there is less damping at that altitude, so not only is the aircraft flight control system in a degraded state that is not normally seen outside of a demonstration in the simulator during initial training, but it was in a flight regime most pilots today have never “hand-flown” an aircraft at due to RVSM rules.

With such a sudden change in aircraft dynamics coupled with the low damping at altitude, it is not surprising, then, that the pilot was focused on trying to keep the wings level, which was occupying a good deal of his ability.  It also would not be unusual for a pilot to be subconsciously pulling a bit with each lateral control input.  Furthermore, the flight directors, which were biasing in and out of view, were commanding a pitch up.

The pilot pulled the controls back enough to increase the g-force momentarily.  This led to an increase in angle of attack to the stall warning threshold.  The stall warning responded with a momentary “Stall, Stall”, but discontinued before the “cricket” tone was generated.  The monitoring pilot in the left seat asked “What was that?”, but beyond that, the Air France crew did not discuss this momentary indication.  Did they just attribute it to turbulence?  Based on the lack of any secondary indications, it is very possible that they assumed that the momentary warning was connected with the lack of airspeed indication.  This is a training problem, as modern stall warning systems on transport aircraft utilize angle of attack.  However, the aircraft continued to fly normally.

Although not discussed by the crew or mentioned in the BEA report, flight tests reproducing AF 447 clearly showed buffet.  It is hypothesized that the pilot perception of buffet may be strongly linked to fuselage flexibility, so the g-forces generated by the buffet might not represent what the pilots are actually experiencing.  These might lead to a pilot mistaking buffet for turbulence.  It is also possible that, while in the turbulence, the buffet is somewhat masked, or perhaps not as salient as the turbulence itself.

Many have wondered why the crew might have ignored the stall warning in the first place. It is likely that they viewed it as a false or spurious warning.  Perhaps they just assumed it was another system failure associated with the loss of airspeed. Several crews reported that in previous probe icing events they had a single stall warning sound but ignored it as being “a blip”  Regardless, this likely had an effect on the subsequent stall warnings, as research has shown that when a system warning is perceived to be false once (accurately or not), people will ignore subsequent warnings.  As they continued to slow, the aircraft entered a stall again.  Again, it appears that the warning was still not accompanied by salient secondary indications, or, at the very least, as described previously, not the secondary indications most pilots have been trained to expect.

Regardless, it is clear that warning was essentially ignored from that point onwards.  No other discussion or mention of it occurred, even when it was repeatedly calling “Stall, Stall..cricket”  The warning was just noise at that point.  If there was buffet it would be easily masked by the turbulence as they flew through the tops of thunderstorms.  The aircraft would be experiencing a gentle pitch up due to aerodynamic factors discussed earlier, but the A330 FBW system would have just kept the pitch constant.  Further, the system trimmed the stabilizer to the full up position.

The stall warning continued for the next two and a half minutes.  Clearly they would have heard it so why did they not react?  Again, the most probable explanation is that they considered it a false warning.  The aircraft AoA continued to increase and it entered a “deep stall”.  The airspeed become so low and angle of attack so high that the stall warning system stopped based on the assumption that the combination would be a false indication.  At that point, a relatively dramatic nose down pitch would have been required to recover, and with full nose up trim, even full forward control stick would result in just a very slow pitch over.  Transport aircraft rarely see nose-down pitches over a few degrees in normal operations, but after reaching this point, the aircraft would have required something in the neighborhood of 15 degrees nose down to start a serious recovery.  Coupled with this, though, was that as the aircraft finally fully stalled it started to descend.  Fast.

The descent rate resulted in the measured g-force falling to around 0.6 g, vacillating between that and .75 g.  Pushing forward on the controls under normal circumstances to get to 15 degrees nose down would be outside the experience of most pilots.  How many pilots would still recognize the need when they were subject to g-forces where they felt they were already falling?  Pilots are taught to “unload” to break the stall, but what if they are already “unloaded”? Under normal circumstances a stall at this altitude could require more than 5,000 feet to recover.  In this case, would have taken much more.

In addition to the confusion the crew was experiencing regarding what was happening, there was also a good amount of oscillation in roll.  This is likely due to the aerodynamics of very high angles of attack, where the flow can have some very difficult to predict effects.  The pilot flying had all he could do to try to keep the wings level.  Sadly, allowing the aircraft to “roll off” might have pushed the aircraft out of the stall, but they did not know that.

In conclusion, it should be clear that the aspects surrounding high altitude stalls are complex.  As outlined in previous articles, expectation bias and confirmation bias play their parts as well.  In truth, there was really not a lot of time to sort it all out, and simulators are not able to replicate the situation adequately.  It is hoped that this article will provide some insight and “food for thought” for pilots confronted with such a situation.  For those interested in more on the topic, may I recommend my book written with Roger Rapoport, “Angle of Attack“.  We explore this and many other aspects in much greater detail there.

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Salient Symbols and the HUD

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Heads Up Display

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There are those that dislike using a Heads Up Display, or HUD ( such as pictured above), but in my experience, once a pilot is used to the HUD it becomes as indispensable as the Primary Flight Display (PFD), which is now the “standard” for most modern aircraft.  Like the HUD, though, many might not recall that the PFD also took some get used to at first.

I still remember that the first time I used a PFD (see below) I found the volume of information overwhelming.  Later, even after being qualified on the aircraft (and while I was more than capable of utilizing the features needed to be safe), I was still “discovering” aspects I had not noticed before in the “information overload” when it was still new to me.

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Primary Flight Display

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Similarly, I recall a time when just having a Horizontal Situation Indicator (HSI) took some getting used to, with several instruments combined (pictured below).

 

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Horizontal Situation Indicator

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Like the others, the HUD becomes a “foundational” instrument, that we come to depend on.  Yes, we can still fly the aircraft without it, but that is also true of the other instruments.  We become accustomed to finding information in certain places, and there is information readily available on the HUD that is harder to find, or in some cases, just not available on other instruments.   Obviously it can be “worked around”, but once one is used to having a certain amount of information it is never fun to give it up.  An analogy might be going back to lower paying job.  Sure, you could make ends meet, you did it before, but it requires readjustment.

On that basis, I recently came across an aspect that is somewhat unique to the HUD where I could see it leading a pilot astray, and that is the flight director, or “guidance cue”.  Flight directors can lead pilots to do the wrong things even on a standard display.  The flight director is, essentially, telling the pilot how much to bank or pitch the aircraft in order to fly to the programmed course or altitude.   Essentially, it is a visual portrayal of what the autopilot would do, and allows for very precise flying with the pilot retaining more control than is present if the autopilot is engaged, plus adding the capability of be able to fly into very gusty winds or with certain flight control malfunctions that the autopilot is unable to handle.  By utilizing the flight director (see image below), the pilot gets the “best of both worlds”, and many pilots come to depend on it, despite the admonishment that they should “look through the flight director” and just use it to “back up” what they would do without it.

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flight director

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Looking through the flight director and flying the aircraft based on the attitude indicator becomes second nature with a bit of practice when utilizing a standard artificial horizon with flight director, or with a PFD.  The entire attitude indicator is easy to visually “take in” with one glance.  Enter the HUD.

On the HUD, the focus is much more narrow.  When using it, it takes a fairly large shift of the eyes to look at different aspects.  The little angle of attack indicator is “way up to the right”, or the autopilot mode is “way up on top”, etc.  It is not just right in front of you like it is on the PFD.   Similarly, the entire attitude indicator display on the HUD is a “big sweep” of vision.  From a visual perspective, the HUD takes up the majority of the view out the windshield, so it appears as one really big instrument! The image that one normally is looking at is something like the following:

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HUD

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Notice that the first “tick mark” above and below the horizon is just 5 degrees.  The pitch attitude is about 2.5 degrees in this image, with the “guidance cue” on the horizon.  While this was in cruise flight, on takeoff there is a large gap between the actual aircraft attitude and the guidance cue.  While the aircraft is pointing up fairly steeply, its climb angle is actually quite a bit less, with easily 10 degrees between them, perhaps more.  The little wings symbol for the attitude symbol is up around 15-22 degrees or so, perhaps higher on some aircraft,  while the guidance cue is still pointing to the actual flight path.  The problem is that due to the scaling, as you can see, 5 degrees is already quite a visual distance off the horizon, and 20 degrees is pretty much near the top of the scale, meaning that the pilot needs to look up near the top of the windshield, literally, to see the actual aircraft pitch attitude.

Meanwhile, the flight path vector display stays at the center of the display, and the pilot is aiming to lay the flight path vector on that guidance cue, which means that the guidance cue is also probably in view at center stage of the visual field.   What this does is make the flight path and guidance cue much more salient than the actual aircraft pitch attitude, with that indicator being up near the top of the visual field.  That is all fine if all is working normally, but if the system were to be commanding too steep of a climb due to some anomaly it is very possible that the pilot might not see or realize just how high the pitch is getting before it is too late. This could create a critical situation in certain circumstances on approach as well.

While this is a potentially dangerous situation, once a pilot is aware of this, then it is easily handled, and does not offset the safety enhancements of the HUD in my opinion.  I put this out for pilots to consider, as it is a potential trap.  Remember to take a peak “way up”!

 

 

 

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Are you an “expert”? Does your airline train you as an expert?

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Are you an “expert”?  Do you think that the industry, the public and regulatory agencies expect you to be an “expert”?  Are you being provided the tools you need to become an “expert”?  Do you need to be an expert?

I have been a bit busy of late crunching numbers and researching some aspects from some closed accident and incident investigations, but thought it time for a short post regarding flight training.  I have been reading a book by Dr. Robert Hoffman et al (2013) that discusses how to obtain expertise as quickly as possible.  The study’s impetus came from a tasking from the Defense Science and Technology Advisory Group, which was looking for ways to ensure top levels of expertise in various military personnel.  Much of the focus lends itself very well to the job of pilots.

We see automation errors that are a direct result of the pilot not fully understanding the automation, how it interacts with other systems and how to predict what it will do next.  I will save more for a future article, but thought that the following might be of interest.  These are guidelines for effective instruction towards the creation of someone who will be an “expert”.  It would seem to follow that if someone is already an “expert” in the field, that if they are learning a new, but related skill (such as a new aircraft type), that these would be the minimum that should be accomplished (p. 31):

  1. Learning activities must provide multiple representations of content;
  2. Instructional materials should avoid oversimplifying the content domain and support context-dependent knowledge;
  3. Instruction should be case-based and emphasize knowledge construction, and not just the transmission of information;
  4. Knowledge sources should be highly interconnected rather that compartmentalized.

Do you feel your training has met these minimum standards?  Would it make a difference if it did?

Reference:

Hoffman, R. R., Ward, P., Feltovich, P. J., DiBello, L., Fiore, S. M., & Andrews, D. H. (2013). Accelerated Learning: Training for High Proficiency in a Complex World. Psychology Press.

Posted in Safety

What is of interest

For those interested, I often post articles I come across that are pertinent to my Jet Safety Facebook site:  https://www.facebook.com/jetsafety.

These include items I have written as well as articles I have come across that are of interest to flight safety.

Posted in Safety

Video of a Downburst

By Captain Shem Malmquist

In a previous article I discussed the need to tilt the radar higher when in the terminal environment in order to be able to paint the area of the storm where the threat is present.

Today, courtesy of the Memphis ARTCC Center Weather Service Unit, an excellent visual of the situation was presented.  Here is their description of the event:

“This cell was at the end of a long line of thunderstorms that reached all the way to eastern Kentucky. It developed just south of the Mississippi/Tennessee stateline in northern DeSoto County. The resulting outflow boundary caused a wind shift at MEM, forcing the control tower to change the landing and takeoff direction at the airport. This is just one of many ways that CWSU Meteorologists keep aviation customers safe from hazardous weather. (Images courtesy of GR2 Analyst).”

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(Click the image above to start the video).

This video starts as the downburst is already in progress, but notice that even though it already has started, the heaviest precipitation is still at almost 20,000 feet!  The bottom of the “red” is at around 10,000 feet still, but heading down fast.  If an aircraft were scanning at the typical 3,000-5,000 foot level, they would see just light rain!  Further, until that downburst gets lower and starts fanning out horizontally, there will not be anything to trigger a windshear alert from ATC or an airborne Windshear Detection System.  If a microburst alert system is installed it will trigger an alert for protected runways within the alert area.

This is why it is vital that pilots adjust the tilt upwards enough to see if there is anything up there that is about to head downhill.  How far up?  If you are within 10 miles, you will need 15 degrees to just get to 15,000 feet at the 10 mile range (note that is STILL below where that heaviest precip is at the moment this video started, and the heavy precip was likely higher a moment before).  Closer in and the radar beam will not even get that high (recall the tilt formula, 1 degree is approximately 1,000 feet at the 10 mile range, so just 500 feet at the 5 mile range).

Have autotilt?  Remember, the engineers that programmed the autotilt had no better information as to where to tilt the radar than you do.  If you depict altitudes, utilize them to view the storm at the higher levels as well.  New system without a tilt control?  It will show you areas of return “outside” of your flight path in some manner (depending on the system), such as a hashed return.  Just remember that a storm that has more water above than below is a bad situation!

Utilize ATC.  Controllers have a lot better picture of the vertical development than you do. Tilt the radar upwards and see what is there.  This is not to say that you should leave it there, but you do need to see what is heading down towards you.  If there is heavy precipitation up high and less below, there are not many scenarios that can lead to that. One is a downburst, another is virga, and the third is hail (if you can think of more, let me know!).  In any event, heavy rain up high and less below is not something that is likely smart to fly underneath!

Posted in Safety | Tagged | 2 Comments