The Fatal Flight Instruction: Spiral Dive Technique
A reader contacted me about a fatal crash which killed a pilot and his instructor in November 2021. The reader had some specific questions, which I answered as best I could. However, a few aspects aren’t that clear cut, so I told him I would post it to Fear of Landing and see what other commenters had to say about it. Think of it as a guest post, except that you are the guest and half of the post is in the comments.
The final report (ERA22FA058) came out January of this year, so it was under work for over two years, which I found surprising.
The aircraft was a Cessna 172S, registered in the US as N90559. There were two on board, a private pilot and a flight instructor, both of whom were killed in the crash. The flight was instructional.
The Cessna 172S climbed to 6,400 feet and flew northwest for about 17 minutes. Everything up to this point looks normal.
One of the pilots on board, likely the private pilot, reduced the power and pitched the nose up, intentionally slowing the aircraft and putting it into a stall. The stall speed is cited in the docket as 53 knots. Whoever was flying that day appears to have intentionally slowed the aircraft to 28 knots.
Then the left wing dropped and the nose pitched down. This could have been an intentional extreme entry into a spin or a loss of control as a part of the excessive stall manoeuvre or possibly a combination of the two. Regardless, the aircraft entered a dangerous descent at 8,000 feet per minute.
The Cessna 172S crashed into the ground, destroying the cockpit. The fuselage was crushed and the wings only partially attached to the fuselage, with damage to the ailerons and flaps. However, the cables from the cockpit controls to the flight surfaces were still attached and all of the damage seems to have happened on impact. There was no sign of any issues with the engine before it crumpled. There were propeller slash marks on several trees at the scene: that is, the aircraft was under power and the propeller was turning as it crashed.
The report is only seven pages long and half of that is forms. I’ll repeat the main narrative here.
HISTORY OF FLIGHT
On November 11, 2021, about 1048 eastern standard time, a Cessna 172S, N90559, was destroyed when it was involved in an accident near Hampton Township, New Jersey. The flight instructor and a private pilot were fatally injured. The airplane was operated as a Title 14 _Code of Federal Regulations _ Part 91 instructional flight.
A witness in the vicinity of the accident site reported that he heard an airplane maneuvering near his home and noticed various engine pitch changes. He listened to the airplane for a few minutes before returning home. Upon his return, emergency vehicles were in his driveway, prompting him to report what he heard to the authorities.
An airplane performance study was conducted using data from the airplane’s Garmin G1000 integrated flight instrument system. The G1000 recorded time, position, altitude, attitude, airspeed, acceleration, and engine parameters. The data indicated that the flight departed Essex County Airport (CDW), Caldwell, New Jersey, around 1029. The airplane climbed to a cruise altitude of about 6,400 ft and maintained a northwesterly heading for the first 17 minutes of the flight.
At 10:46:30, the airspeed began to decrease due to a power reduction from about 2,400 rpm to 1,300 rpm. Shortly before 1047, the airplane pitched nose up, reaching a maximum pitch attitude of about 37° at 10:47:04 as the airspeed slowed to 28 knots indicated.
At 10:47:10, the airplane reached a left-wing-down bank angle of 102° and a nose-down pitch attitude of 79°. The G1000 recorded the airplane’s descent rate at over 8,000 ft/minute 3 seconds later.
The recorded airplane data indicated that the pilot initiated a recovery attempt between 10:47:10 and 10:47:30. The pitch attitude increased to 32°, the rate of climb rose to over 2,000 ft/minute, and the airplane was wings-level for 20 seconds as power was increased to 2,400 rpm. However, airspeed only momentarily recovered at 10:47:16.
The G1000 did not capture load factors for the final seconds of the flight, likely due to buffering between volatile and non-volatile memory (See “NTSB Vehicle Performance Study” in the public docket).
A surveillance video from a camera located at the Sussex County Sheriff’s Communications Center showed the airplane in a very steep spiral turn, continuing this maneuver until it was out of view of the surveillance camera.
Here is the surveillance video showing the aircraft shortly before it crashed (Warning: shows an aircraft clearly falling out of the sky):
The final report includes background info on the pilot and the flight instructor, but the relevant point from this section is that the pilot’s logbook showed that he had often flown with the flight instructor for training in a “steep spiral turn” manoeuvre.
The “steep spiral turn” is a maneuver requiring specific techniques, and if not executed correctly, common errors can occur. These errors are outlined in the Airplane Flying Handbook (FAA-H-8083-3C), Chapter 10, Performance Maneuvers. Understanding and addressing these potential errors are crucial for safe flight operations.
You can read Chapter 10 of the Airplane Flying Handbook online. The common errors for the steep spiral are on page four:
- Not clearing the area
- Inadequate pitch control on entry or rollout
- Not correcting the bank angle to compensate for wind
- Poor flight control coordination
- Ineffective use of trim
- Inadequate airspeed control
- Becoming disoriented
- Performing by reference to the flight instruments rather than visual references
- Not scanning for other traffic during the maneuver
- Not completing the turn on the designated heading or reference
I find it a bit disingenuous to point to this list without digging deeper into how it is relevant to this accident.
The Probable Cause and Findings reads as follows:
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The flight instructor’s failure to recover from a steep spiral turn during an instructional flight.
If you want to see the detailed data from the final moments of the flight, then take a look at the Global Positioning System Device – Specialist’s Factual Report. Also in the docket are images of the wreckage (including what I posted above) and the invoices from the instructor, charging for flight instruction in the following: Lazy 8s, Chandels, Steep Spirals, Soft Take Off and Power off 180. The manoeuvres trained vary per invoice but Steep Spirals appear on all of them.
Here are the questions from the reader:
- Is 6,400 ft too low to practice a “steep spiral turn”?
- Was recovery attempted too late? Was the plane already doomed by the time power was increased?
- What does “the rate of climb rose to over 2,000 ft/minute” mean? I assume if they were climbing, it wouldn’t have crashed.
- Is 79 degrees nose down too steep to practice this maneuver? At a descent rate of 8000 ft/min, obviously you only have about 30 seconds to recover, is this normal for a student? Did they perhaps think they had longer and just misjudged their descent?
- What exactly did the instructor do wrong here? Page 4 just says “He should have read the handbook” but not what mistake he made.
I mailed with some thoughts but now I’d like to hand it over to you! I’m hoping you will fill the comments with your thoughts and explanations of this tragic crash. If you have not commented before, your comment will take a while to appear as I use manual methods to stop spam. However, I’ll get your comment added as quickly as possible and once I’ve approved you, your comments will go straight through in the future.
Remember to be nice.
Those are all maneuvers required for a Commercial certificate (I am just about to start my airwork and learning those maneuvers). Maybe once I start my own training I will understand what went wrong in this scenario. Reading this definitely confirmed my decision not to practice this on my own despite 1,500 hours and some acro training!
In this type of aircraft, when a stall is imminent, the entire intrastructure of the plane starts to shutter or stutter or shake. My instructor would never advance the training much further than about one second past this stage, citing the danger and the unnecessary risk. The very second that the plane ceased any forward motion, the correct altitude and speed was to be resumed. In my FAA test flight, the examiner told me to put the airplane into a stall. I said that I was willing but also explained my instructor’s technique. The examiner allowed me to demonstrate and passed me for that part of his exam.
In a real stall that quickly proceeds into a severe spiral, I can imagine that panic and fear could have caused the pilots to actually do the exact opposite of the correct maneuver. In a worse case, this could be suicide by airplane. Despite the technical analysis from the investigation, we may never really know the root cause.
Looking at the flight path, at 10:47:07 they were in the first left turn at 25.06 knots, so presumably stalled. The report mentions they recover to wings level, at 10:47:15 they’re 730 feet lower at 91 knots. But then at 10:47:22, after a straight bit, they find themselves 230 feet higher and 32 knots slower. They lose more speed, then there’s another steep left turn, but the aircraft never recovers speed or arrests the descent.
My understanding (please correct if wrong) is that the aircraft stalled and spun left, the pilot put the aircraft in a dive, picked up speed, and (momentarily) recovered–an aircraft that climbs has lift and is not stalled—, but were pitched up too much and climbed quickly, again losing air speed as a result. Trading speed for altitude, the air speed bled off, and in under 10 seconds, the aircraft was below stall speed again, and entered the final spiral from which it did not recover during the next 30+ seconds.
My questions:
1) Should the pilots have been able to achieve level flight on the straight bit, and thereby avoid the accident? Or was that impossible aerodynamically?
2) If “yes” to 1), could it have been impossible through a mechanical defect? like, the pilot pulls out of the first dive, but now the elevator is stuck?
3) If “yes” to 1), what could have happened that allowed them to recover from the first stall, but not the second?
4) Is it possible that the aircraft pitched up more, and then fell tail end first? I expect that this could only happen with the center of gravity (CG) badly out of whack, and I expect that would’ve been noticable before, and maybe even prevented recovery from the initial stall. Also, the propeller couldn’t have slashed the trees at the crash site, so my answer would be “no, that’s impossible”. But is this correct?
5) Would it be common for an instructor to initiate two stall maneouvers back-to-back?
I’m thankful for any insights.
(This was meant as a general comment, not a reply to Kenneth specifically—my bad.)
Is 6,400 ft too low to practice a “steep spiral turn”?
No.
Was recovery attempted too late?
Yes.
What does “the rate of climb rose to over 2,000 ft/minute” mean?
Severe level of Nose Up attitude.
Is 79 degrees nose down too steep to practice this maneuver?
Yes.
At a descent rate of 8000 ft/min, obviously you only have about 30 seconds to recover, is this normal for a student? Did they perhaps think they had longer and just misjudged their descent?
There is no reason to practice this for any amount of time after the nose starts to pitch downward. At that point the stall has begun. Avoiding/recovering from a stall, and recovery from a dive, are two different things.
What exactly did the instructor do wrong here? I assume that the mistake was invoking a dive which is the result of a stall and not necessarily a part of the initial stall, a dive is the result of a continuing stall. Once the stall has begun, a dive is not imminent, if recovery measures are immediately initiated.
After doing a similar training session many years ago with my instructor I recall we were about 7000 ft . I was wearing the face mask ( so I couldn’t peak) while my instructor flipped the plane ( a Gruman Trainer) into a wing over and a 35 degree downward spiral.. When given permission to look ( only at instruments) I easily got us back in a few seconds.
So with that as a reference I believe when the instructor (must have) wanted to take control ,the pilot must have panicked, held onto the controls, and froze thereby causing the crash. Instructor is not to blame …seeing as how the one flying was noted to be a ” private pilot” in the introduction to the story. Also 6000 feet does seem a bit low for this maneuver
Steep Spirals are a performance maneuver for Commercial Pilot certification. The angle of bank and pitch attitude in the accident report are way in excess of those specified for the maneuver. It appears the airplane was being operated outside of its manufacturer specified limitations, most likely in a reckless manner which led to this tragic accident. It is very unlikely this flight was for serious flight instruction. Unfortunately, some pilots behave in this manner but they are not representative of professional flight instructors.
“”he had often flown with the flight instructor for training in a “steep spiral turn” maneuver.”” I find this odd. It’s not something you would do for fun. Perhaps the student or the instructor found it exhilarating, or perhaps the student had never done it successfully and needed continual training before attempting a license test. Either way, it was a ridiculously extreme entry. I’d like to see more on the instructor’s background in this maneuver. Did he use that technique with other students?
When I did my Tiger Moth conversion the instructor (who was said to have 14,000 hours on the aircraft as a wartime primary instructor) used a similar approach to spin entry – nose high, very slow and hard rudder which flicked the aircraft over the top into a violent spin. Not in the least like the most probable accidental entry off a too-slow and steep final gliding turn. I think that extreme maneuvers should be taught in the most likely circumstances.
I flew with Tom before. Started flight training at 15. He wasn’t my CFI, but was the owner of the flight school and chief CFI. I flew with him on stage checks. I moved down to PA and finished my PPL at a different school. Came back and flew with Tom once more after getting my PPL, and during the flight he had a macho attitude and didn’t speak much (which seemed odd). Later in the flight he took the controls and demonstrated an “emergency descent”, which involved a steep spiral to quickly lose altitude (a maneuver for e.g. an electrical fire or some other emergency requiring imminent emergency landing). He recovered and then told me to find my way back to the field without GPS. I hadn’t seen Tom do this before, but maybe he felt more comfortable doing it with non-students / PPLs.
From my experience (and reading this report), I would guess Tom intentionally put the plane into an extreme maneuver to impress Glen de Vries (who had recently come back from a 0g space flight). Some sort of combo of a stall/spin and steep spiral or emergency descent. The security camera footage shows the plane clearly in a spin. I think this was a case of showboating taken too far, entering an accelerated spin that was difficult to recover from (maybe inducing panic).
Tom had a sign on his flight school’s wall saying “the extraordinary pilot uses his extraordinary judgement to avoid situations that require extraordinary skill.” It’s sad to think he likely died in a lapse of following his own good advice.
Aircraft was at 6400’ town of the accident was Branchville, New Jersey elevation of 554’ so it’s possible to have had aprox 5900’ or less depending on the elevation at the crash site.
Figure 7 in that report is interesting.
We see the fuel flow/engine RPM reduced three times.
slowly reduced over 7 seconds (10:46:33 to 10:46:40), presumably by the instructor. Pilot restores fuel flow to full throttle at 10:46:52, well before the aircraft goes into its first spin. I am guessing that’s when the aircraft starts to stall.
sharply reduced at 10:47:10, restored to full throttle after 6 seconds. At this point, the aircraft is diving and picking up speed, and the pilot may have wanted to counteract that.
sharply reduced at 10:47:34, at this point the aircraft was momentarily picking up (indicated) air speed in the second stall. The throttle never came back up as IAS/TAS fell below 0 knots twice.
I don’t understand that third throttle reduction.
Was the second reduction even a good idea?
David Provan describes a spin entry in a Tiger Moth. He forgot something: for intentional aerobatics in this aircraft, the slats had to be in the locked. position. Thanks, it brought me back to the days when I was a member of the Tiger Club But it was not really necessary to make such a dramatic entry, it could be performed (after the “HASELL” checks”) to bring the aircraft close to the stall from level flight, kick the rudder hard whilst holding opposite aileron with the stick aft. As the Gipsy engine turned the other way from the American engines (anti-clockwise as seen from the cockpit), it would more easily enter a spin to the right.
The spin is more or less self-sustaining. At least, in classic aircraft like the DH82. Initially, the nose falls quite sharply but if the spin is allowed to develop it tends to flatten. The rotational forces act in an opposite way on the airframe, they exert an outward force created by the rotation. The wing on the inward of the spin has a lower airspeed than the wing on the outer side. Thus the inner wing will remain stalled, whilst most of the lift is generated by the outer wing. This is rotating faster, therefore has a higher airspeed and may not even be fully stalled. From this it will be apparent that in a spin the rate of rotation will be high, the loss of altitude was in the order of between 800 and 1000 fpm, but the IAS remained low. If recovery is not initiated in time, the aircraft may not recover from the resulting “flat spin”. Recovery would take some time, “rocking” the elevators and alternating application of power would assist recovery. But the engine might even cut out.
The Dutch CAA (“Rijksluchtvaartdienst”) at the time mandated an enlarged tail fin, a modification to overcome this problem.
Normally, a pilot practising an intentional spin would not allow the spin to fully develop; after 2, maybe even 4 rotations the drill was: stick fully forward, full opposite rudder, ailerons neutral. When the rotation stops and airspeed builds up: neutral ailerons and rudder, ease out of the dive (gently does it!), apply power and build up airspeed.
Is 6400 feet too low? Depends of course on the terrain below. Remember the three most useless items in aviation?
The runway behind you,
The airspace above you,
and the fuel that you left behind.
Usually, 3000 feet is enough, of course it depends on the type of aircraft. Small aerobatic aircraft with relatively low wing loading factor can recover relatively quickly. I have seen a former WW2 fighter pilot do aerobatics, including spins, on a windy day with gusts of up to 25 kts in a Tiger Moth, not higher than about 1500 ft. above the ground. At the time he was probably approaching 60 years of age.
I must admit that I have never heard of a “spiral turn”. Presumably this is an exercise better known as a “spiral dive”. Which is exactly what “it says on the tin”: the aircraft is in a tight nose-down spiral with an increasing bank angle, and increasing airspeed.
A “classic” accidental entry into a spiral dive is an overtight turn at low altitude, at a low airspeed.
This all too often occurs when a relatively inexperienced pilot realised that (s)he is going to overshoot the approach centreline from base leg.
The aircraft may already be in an approach configuration, wheels down (or bolted in place). Rather than leaving his or her place in the sequence with a go-around, the pilot tightens the turn.
That will cause the nose to drop, so elevator is applied to raise the nose. But remember: in a steep turn the elevator takes over partly from the rudder; it tightens the turn, the nose drops further but in this situation, even though the stall speed increases, usually the engine remains at a high power setting. This prevents the aircraft from stalling. So in fact the situation rapidly gets out of control: Bank angle may even get to over 90 degrees, partially inverted, the airspeed increases and so does the rate of descent. This can increase in very short time to thousands of feet per minute.
In a real-life situation, often there is not enough room between the aircraft and the terrain to recover. The pilot all too often is disorientated long before (s)he realises what is happening. Confused, the proper recovery – if initiated – comes far too late.
In this case, the aircraft descended at 8000 feet/ minute. It is very likely that any attempt to recover would have overstressed the aircraft. Maybe to the point of structural damage or even break-up in mid air.
A few comments point to the fact that this is part of the syllabus for the commercial pilot’s licence. Its purpose is to demonstrate what can happen when a pilot gets distracted, overbanks and allows the nose to drop. Since this often occurs when the pilot is looking at the terrain, or other traffic, (s)he may be startled when the nose if pitched too low down and at a low altitude. Automatically, elevator is applied; precisely the wrong action.
An experienced instructor cis supposed to teach the student how to recognise the situation that they are in, and the proper recovery.
Which is, and should be performed instantly::
Check instruments(airspeed, rate of descent). Assuming the engine is running at high power, simultaneously close the throttle(s) and gently ease off the bank with the ailerons. The airspeed may be high: gently ease out of the dive. When the aircraft is stable and the speed is under control: feed the power back in. Climb gently back to a safe altitude. Do not overcontrol, level off when safe. Do not keep a high nose attitude with low power, or the aircraft may stall. Take stock of your environment. Contact ATC.
This can be a very scary and even dangerous manoeuvre.
Many years ago, I worked with a pilot who had been an instructor.
During a spinning exercise the student froze on the controls. He was strong and the instructor could not overpower him.
They spun into a lake. The student was killed, the instructor needed facial reconstruction. He tried to return to flying, but he never regained confidence and had to give up his career.
The antics of the two pilots in this blog do not seem to point to a student freezing at the controls. They had gone through the spiral dive scenario before.
Yes, it is possible but in my mind it seems that they were exploring the limits. And exceeded them.
Some questions have already been answered.
What is important to know is that both a spin and a spiral diver cause a very high bank angle, and a rapid loss of altitude.
Seen by an observer from the ground they may look similar: both involve a rapidly spinning aircraft falling from the sky.
So:79 degrees bank angle? Not really a safe angle..
What did the instructor wrong? Well in my view the two were practicing a manoeuvre that was not in the syllabus for the level of the student.
And it seems that they were playing around with it a bit.
The instructor should have ended the exercise well before it was too late. Was it within his level of competence? From the sad outcome it would seem that he did not initiate recovery in time.
So the answer must be: he probably was NOT competent to instruct in this manoeuvre.
Very sad.
Interesting discussion. Per the flight description and some of the other comments here… Doing two sequential spiral turns (without solidly recovering to level flight, and ideally gaining altitude in between) was either completely irresponsible or a something caused/induced by one of pilots. I’m hard pressed to believe an instructor would do this intentionally. Knowing if the instructor had a history of actions like this would be interesting to know. Assuming not, and if no mechanical control surface failure can be identified, then I’m leaning towards the student somehow inducing this. (i.e. freezing on the controls, suicide, etc).
However, what explains how you could almost recover properly from the first stall, which shows some skills/ability, but then induce a second stall, and hold on to it until the end? There’s no logic to these actions, unless it was purposeful. If you wanted to end your life, maybe you’d want to be a little closer to the ground before starting, thus giving less time for anyone to intervene. (This assumes it’s wasn’t the instructor who was suicidal, but then why would they take a student up to end it?)
It’s hard to comment on something like this when suggesting blame. I mean no offense, regardless of the cause, tragic accident or otherwise.
Glen Miller is absolutely correct. It makes no sense whatsoever.
The aircraft decelerated to … what, 28 kts? Attitude 37 degrees pitch-up, That sounds like a very abrupt, deliberate stall. A wing dropped. No wonder.
That scenario is a classic spin entry, only the very high descent rate of 8000 ft/min and near vertical attitude contradict it.
It would seem that the pilot initially kept the aircraft in an extremely steep dive, but the report here makes no sense either:
“… the pilot initiated a recovery attempt at 10:47:10 and 10:47.30. The pitch attitude rose to 32 degrees, the rate of climb (???) rose to over 2,000 ft/minute, and the aircraft was wings level for 20 seconds as the power was increased to 2,400 rpm. However, airspeed only momentarily recovered at 10:47.16.”
Unfortunately, the actual airspeed – assuming that this has been preserved – is not mentioned. Following the time line: the rapid stall was more than likely deliberately initiated at 10:47.04.
The aircraft slammed into the ground at “about 10:48 eastern standard time.”
So in the space of only a few seconds, the aircraft went into a more than likely deliberately induced stall with a high pitch and very low airspeed. It went into a spiralling descent, judging from the rate of descent a spiral dive with a nearly vertical nose-down attitude.
Somehow, it recovered, it suddenly assumed a rate of climb of 2000 ft/min. For a C172 that is a very high climb rate even with wings level and 2,400 rpm.
Yet, only about 6 seconds later the aircraft seems to have entered a fatal spiral dive.
The only thing that struck me as an explanation, however far-fetched: The damage to the aircraft won’t enable an investigation into this:
Did the aircraft have a leak in the exhaust? The heating system in light aircraft is often fed by a muffler that takes heat from around the exhaust to be fed into the cabin.
Unless there is a typo in the description of the last minute (it is not even “minutes”) of the flight, the antics of the crew and the weird flight pattern of the Cessna make no sense at all to me.
Rudy, examine the flight path picture that Sylvia published. It has time/altitude/airspeed on points about 10 seconds apart.
Sylvia also links the specialist’s report, which has continuous graphs of this, with fuel flow added.
I promise this is my last diversion into Tiger Tantrums. Rudy, you are right about the slats being locked for aeros, but I always locked them except in the circuit. My preferred entry for a training spin would be off a steep, slow gliding turn – the aircraft falls gently into a spin with no need for overuse of controls, just what is likely to happen unintentionally in the circuit.
Re Tiger spins, initially the aircraft had no VNE – you could point the thing straight down and drag would stop it going too fast. However, some were lost in flat spins and one of the solutions tried was anti-spin strakes ahead of the tailplane, to stop the rounded fuselage top generating lift. The real solution was to remove the aileron mass balances, whose weight was locking the aircraft into a flat spin. This meant that a VNE of 170 mph was imposed to avoid flutter. In my youth I used to enjoy this speed until once I tried it in a Tiger used for glider towing, with a rear vision mirror. As speed increased I could see the rear fuselage and tail assembly rotating anticlockwise… never did it again.
David
David,
Yes, happy memories of happy days.
The Tiger Moth of course was constructed of wood. The condition of this material, as it ages, is probably not as easily to determine as metal.
I have never heard of “wood fatigue”, but I do remember that a few Stampe SV 4 biplanes (the Tiger Club owned a few as well) came apart in mid air during aerobatics.
I much preferred the Stampe for aerobatics. It had ailerons on all 4 wings and it was much more manoeuvrable than the Tiger. The ones that the Tiger Club operated were fitted with an inverted carburettor system. Switching over was a bit elaborate and involved stopping the engine in mid air. I remember that my heart also missed a few beats until it picked up again.
The Stampe had a tail wheel and brakes, so it was a lot easier to taxi, even if we still had to weave from left to right for some form of forward vision. I believe that many surviving Tiger Moths now have a tailwheel conversion. The days of grass airfields are numbered.
My spin training for the PPL was done in a Cessna 150. The “Aerobat” version had not been introduced yet. I remember looking at the tail through the back window. That also twisted during the spin; I did not really like it but apparently the C 150 was well constructed. I never heard of a standard 150 breaking up doing spins. Actually, one of the instructors was in a habit of doing loops with the (non-aerobatic) 150s, especially after a few pints of Heineken that he enjoyed between sessions. Yes, things have changed !
When I was checked out on the Cherokee my instructor, Colin Horsfall, declined to spin that type of aircraft. He did not say with so many words why not, but he made it quite clear that he did not consider that aircraft suitable for spinning.
Mendel, I was trying to make some sense of the written report. I will look at the track that the Cessna followed, but I doubt that my assessment will change: A deliberately induced manoeuvre that the pilots allowed to go beyond the point where recovery became impossible. Or, also second-guessing, a case of pilot incapacitation.