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# L-29 crash at Argentine Airshow 12/11/23

Accidents and Close Calls Discussion on accidents, close calls, and other unplanned aviation events, so we can learn from them, and be better pilots ourselves.

# L-29 crash at Argentine Airshow 12/11/23

6th Dec 2023, 23:42

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Originally Posted by Pilot DAR
I have questions: What is/is there a difference between a flick roll" and a "snap roll"? I understand a snap roll to be a spin on a horizontal axis (essentially, the inertia of the airplane carries it along the horizontal path long enough to enter and recover a one turn spin along a horizontal axis - which I have been taught is a snap roll). Was I taught correctly? The forgoing description make the flick roll also sound like a well recovered horizontal spin to me....
Basically it's a simple case of semantics. In the United States we call it a snap roll and in GB it's a "flick roll". At least that has always been my understanding.
The execution is the same really. You slow the aircraft down to a speed where an accelerated stall will produce the stall below the limit load factor. You execute the roll by quickly inducing an accelerated stall with rapid back pressure. As the stall breaks you apply full rudder and in some aircraft full aileron as well to couple the airplane at the stall break. Timing is critical. Get it just right and the aircraft should break cleanly into the roll. You simply maintain control pressures and watch it go around. As you reach level flight again you quickly neutralize all controls to stop the roll.
Each aircraft may behave a bit differently doing a snap roll. It's one maneuver where you have to practice to find the sweet spot where it all comes together to do the roll. You can't initiate early or too late either. There is just that one spot where the stall break and your control application all come together.
Practice.........practice.........practice. It's all about the timing !!!!!!!
Dudley Henriques
7th Dec 2023, 00:18

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One and the same I've always thought DAR. An ocean separating common language again? Flight manuals of US WWII aircraft used to have a page at the back with a glossary of words with the respective US/UK meaning eg battery/accumulator
7th Dec 2023, 02:26
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Thanks for the clarification, (and language lesson). Bill Loverseed used to tell me about flick rolling the Gnat, and in describing it, it sounded like a snap roll. Though I did a lot of flying with him, none was in aerobatic capable types, so I never had training from him in those maneuvers. I used to snap roll the C-150 Aerobat regularly, just for fun. It's decent at snap rolls, though on the lower edge of aerobatic in the main.
7th Dec 2023, 02:32

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Originally Posted by Pilot DAR
Thanks for the clarification, (and language lesson). Bill Loverseed used to tell me about flick rolling the Gnat, and in describing it, it sounded like a snap roll. Though I did a lot of flying with him, none was in aerobatic capable types, so I never had training from him in those maneuvers. I used to snap roll the C-150 Aerobat regularly, just for fun. It's decent at snap rolls, though on the lower edge of aerobatic in the main.
I've always said that if you perform decent aerobatics in the Aerobat you are doing a good job. The "Bat" requires a whole different level of stick and rudder technique. It's a fun little bird and does the basic stuff well. Just takes a bit of "handling" as they say. :-))
Dudley Henriques
7th Dec 2023, 07:39
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Originally Posted by DAHenriques
As an American fairly familiar with flying WW2 fighters I would say without hesitation that were I to go up on a display that included "flick rolls" I would choose as my mount to do that a Spitfire over all other planes of choice, preferably a clean Mk 9 or earlier.
I forgot to mention that Tuck was flying a Mk V at Wright Patterson during and advisory visit to the USA in late '41; he said she was well worn as seemingly every pilot in the USAAF had had a go on her!

Re the semantics, i certainly heard the commentator at Biggin Hill in '76 (John Blake) describe it as a flick roll; a couple of years later my mum gave me James Gilbert's "The Fliers World" for Christmas - an Englishman who cut his teeth as an editor for Flying in the US before moving back to the UK and acquiring Pilot. In the book, written for an American audience, he describes his Jungmeister performing a snap roll, so never any doubt in my then young mind that we had two terms for the same manoeuvre! Isn't the American hammerhead a British stall turn? I'd actually always thought a hammerhead was either a push or a pull instead of a yaw at the top of a vertical climb, but listening to various US show commentaries, I suspect I was wrong!

(Speaking as an enthusiastic warbird and aerobatics watcher!)

7th Dec 2023, 08:56

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I agree with previous posters that a snap roll and flick roll are the same thing. Also, a Hammerhead and Stall Turn are also the same as each other, although the former is a much better term since the aircraft is never stalled during the manoeuvre. (A humpty bump is where you push or pull at the top of the vertical instead of yawing as you would in a hammerhead).
Strictly speaking there is a difference between a flick roll and a "horizontal spin". For starters, a flick can be performed in any attitude. It also differs in that with conventional light aircraft (i.e. not swept wing of which I have no knowledge) a spin will generally have both wings stalled and to maintain the spin you will have full elevator deflection and full rudder. For an ideal flick, the initial pitch is to just at or below the critical angle off attack such that the yaw induced with the rudder then causes one wing to stall and the other to be unstalled. The elevator should then be "unloaded", i.e. moved towards neutral in order to increase the roll rate due to angular momentum effects and to reduce drag. As Dudley says, getting this all just right and finding the sweet spot is the tricky part! Power helps during the figure to energise the tail feathers and counteract the increased drag, but this also creates large stresses on the airframe due to gyroscopics. This and torsional aerodynamic effects are often why maxiumum allowable flick roll entry speeds are relatively low, apart from the need to avoid exceeding the normal aircraft g limits.
7th Dec 2023, 21:37

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DA Henriques. I, like Treadigraph, witnessed the P.38 accident. I also heard of the theory re the kneeboard and the yoke interference. However, talking with Steve Hinton at Oshkosh shortly after, I asked his opinion. Apparently, in Steve's opinion, he pulled the first roll [yes, there were two] too early, and realizing his error, went for the second one with too little pitch and speed. He made the point that Mr. Proudfoot was red in the face with anger just before his display, as the BoB Memorial Flight had completely cocked up the timing of his and others displays. As Steve said, that is no condition to go to fly a tight display, and he felt that it was this state of mind that was possibly the cause of his misjudgement?. Who really knows. It was a very, very sad day. I have read your posts with extreme interest. Many thanks for them.
7th Dec 2023, 22:42

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Originally Posted by JEM60
DA Henriques. I, like Treadigraph, witnessed the P.38 accident. I also heard of the theory re the kneeboard and the yoke interference. However, talking with Steve Hinton at Oshkosh shortly after, I asked his opinion. Apparently, in Steve's opinion, he pulled the first roll [yes, there were two] too early, and realizing his error, went for the second one with too little pitch and speed. He made the point that Mr. Proudfoot was red in the face with anger just before his display, as the BoB Memorial Flight had completely cocked up the timing of his and others displays. As Steve said, that is no condition to go to fly a tight display, and he felt that it was this state of mind that was possibly the cause of his misjudgement?. Who really knows. It was a very, very sad day. I have read your posts with extreme interest. Many thanks for them.
Steve is most certainly qualified to make a suggestion on this incident and I have great respect for his opinion.
This being said I'm sure Steve would be the first in line to say that the circumstances involved with the Proudfoot crash are vague to say the least and questions will remain unanswered most likely forever.
Des Barker and I went over this incident in some detail for his book
Anatomy of Airshow Accidents" and both of us watched the film many times over. I wouldn't argue a thing Steve said and certainly these factors could easily have been pertinent concerning the crash.
Both Des and I were deeply concerned with the second roll. Hoof had done a single the day before and everything that should be in place through initiation and completion was there and completely normal. On Sunday for some reason Hoof decided to go for that second roll. Naturally multiple rolls done in sequence pay a price in drag and energy loss. I was looking for just a bit more positive pitch rate into initiation for that second roll and I didn't see it. To my eye it looked like Hoof buried the nose through inverted just enough that it altered the roll arc backside into dishout. What also got my attention was that at ground impact there was aileron still in the equation. It was this that led both Des and I into the kneeboard theory. In short, barring control interference the control application just didn't seem normal to my eye for a pilot with Hoof's experience in the P38. Added to this was the fact that the buckle attachment that secured the kneeboard to Hoof's knee was discovered undone and separated from his leg post accident. IF.......and that's a huge IF........that kneeboard had come undone during that second roll that could easily have been a direct cause for yoke interference.
BUT.............as we say quite a lot when dealing with conjecture...........who REALLY knows ?
Dudley Henriques

Anyway..........both Des and I agreed that the role of the kneeboard Hoof was wearing on his right leg that day might or might not have been a factor.

Last edited by DAHenriques; 8th Dec 2023 at 06:43. Reason: typo
8th Dec 2023, 06:38

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Originally Posted by DAHenriques
In combat you do what you have to do. Generally speaking when defensive a "flick roll" could be a last ditch maneuver to force a shooter into an overshoot.
The airspeed at which a "flick roll is initiated" is critical. Too fast and you can easily over g the airplane. So slowing it down to where you can safety "snap it" is the key.
Because ANY snap roll in ANY airlane is an energy loss maneuver, doing one in combat should be considered a "desperation" maneuver, not something you would wnat in your normal "bag of tricks" as a combat pilot.
Dudley Henriques
Here is an actual acct, told by my father:

Incident at Le Mans - June 1940

Jumped by a one-o-nine at fifty yards
thought he was one of our flight
looked back at his spinner through green fire
how he could miss - his shower of shells
just clearing my perspex
panicky, yanked the stick to my guts, kicked
full right rudder, a hundred feet over the trees.

The Hurricane flicked upwards - he was still there
closer - another dizzying flick roll
with the speed dropping right away
fell into a spin at seven hundred
they said - curtains, less than a thousand
the ground rushed up incredibly, a clearing -
knew I was dead in five seconds, thought coldly,
you bloody fool, you’ve done it now
the air gripped the wings again, levelled
out of the dive, below the trees, frozen
saw the German beside me, going faster
now I had him, fumbled the sight switch on
gun button off safe
he turned his head, did nothing
flew into my three second burst -
a shiver of wings, then slowly, slowly
half-rolled, falling inverted
down to a cornfield, dissolved in flames

He wrote a bit of prose and poetry much later.
Flew in France with 242, back for the BoB with 32, then Spitfires and channel crossings, some with Finucane. Later N. Aftrica.
DW
8th Dec 2023, 09:42
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Re the P-38 crash which I didn't witness, TFC's Ken FitzRoy quoted Hoof as saying "never more than one roll", presumably during briefings, and having just reviewed the video I see the rolling element is continuous; at the start of the second roll the nose is on the horizon possibly even slightly nose down with no pitch up so far as I can see. Certainly looks more like a problem than a deliberate attempt at a second roll to me.
8th Dec 2023, 13:39

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Originally Posted by Dr Jekyll
What examples are there of old aircraft crashing because they are old or 'worn out'? The most common single factor appears to be misjudgement of speed and/or altitude at low level, and this can happen to current military pilots as much as anyone else. EG The Mountain Home Thunderbirds crash.
This thread is about a jet trainer. a jet trainer when put in private hands, needs extensive training it's fast and whoever is flying it has to be well ahead, mentally and tactically connected to the aircraft in all phases of flight. When talking about a vintage very high power former WW2 propeller driven aircraft, it may even require more attention.

We are talking about over powered, high wing loaded aircrafts to be maneuvered with G load increases, potential dangerous cross controlled inputs whether intentional or not, often on the back side of the power curve.

Huge props, enormous power, pronounced secondary effects ( P factor, torque, slipstream and precession ) conducive to loss of control not only during take off run where full throttle application could lead to flipping to the side or failure to maintain directional control even with full use of rudder; In flight it can and will bite (Flick or snap) in all areads of the backside of the flight envelope, if not handled correctly plus when maneuvering at low level high turning and loop radiuses due to their speeds have to be reckoned with

These aircraft were already twitchy when they were in service back in time, with so many crashes and damages due to loss of control. Nowadays often they are in the hands of pilots which may not have had the training, the competence required. Even when handled by once competent veterans flying every now and then, they may lack in currency.

Flying these birds calls for proper training and currency. I have owned many aerobatic aircraft including for 17 years a sukhoi 29 which can be described as a mini fighter along these lines. It took me years and specialised training to feel confident at my level, and would need much more training to carry on learning, but am too old for that, though I still fly an Sback XA42.

After 45 years of flying I still approach such aircrafts trying to fly on a regular basis, using brains and humility. If I were to be able to have a go in a Spitfire, a P51 or Corsair I would never even think of it without highly specialised tuition..

A wise old man, by the name of Mr Auguste Mudry, the creator of the famous french Cap's aerobatic aircrafts, back in 1992 at the Yverdon Switzerland world unlimited aerobatic venue, during one our many conversation over the years ( I was one of his customers) struck me with a brief sentence ;
Aerobatics is to aviation what grammar is to a language and dressage to horse riding. But there is an extatic euphoria when bonding with an aircraft during aerobatics which could extend to airshows or any advanced aircraft flying, where the confidence gained may not be at par with the skill required and the lapse of time available in terms of margin at low level when one makes an error. This will almost always kill you..

I have scared myself more than once over the years, and am trying the learn the lesson.....At some times I guess I have been lucky,
8th Dec 2023, 16:38

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Sorry, Treadigraph. I thought you had. I should have checked back. I video'ed his roll on Saturday. It was superb. I told my friend on Sunday to watch this beautiful slow roll. Then it happened. Despite being there, I had no idea that this was a second roll. Possibly I was looking straight ahead and missed the first one. The P.38 crashed directly opposite me. Apologies for for the mis-reference. Regards, John. P.S. I was asked at Fairford by another Aviation buff as to what I thought had gone wrong. [he had seen it also], and I replied that it looked to me like a control problem. As Mr. Henriques implies, we will never know the answer, but I now head towards the Knee-pad theory.
8th Dec 2023, 16:48

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Originally Posted by markkal
This thread is about a jet trainer. a jet trainer when put in private hands, needs extensive training it's fast and whoever is flying it has to be well ahead, mentally and tactically connected to the aircraft in all phases of flight. When talking about a vintage very high power former WW2 propeller driven aircraft, it may even require more attention.

We are talking about over powered, high wing loaded aircrafts to be maneuvered with G load increases, potential dangerous cross controlled inputs whether intentional or not, often on the back side of the power curve.

Huge props, enormous power, pronounced secondary effects ( P factor, torque, slipstream and precession ) conducive to loss of control not only during take off run where full throttle application could lead to flipping to the side or failure to maintain directional control even with full use of rudder; In flight it can and will bite (Flick or snap) in all areads of the backside of the flight envelope, if not handled correctly plus when maneuvering at low level high turning and loop radiuses due to their speeds have to be reckoned with

These aircraft were already twitchy when they were in service back in time, with so many crashes and damages due to loss of control. Nowadays often they are in the hands of pilots which may not have had the training, the competence required. Even when handled by once competent veterans flying every now and then, they may lack in currency.

Flying these birds calls for proper training and currency. I have owned many aerobatic aircraft including for 17 years a sukhoi 29 which can be described as a mini fighter along these lines. It took me years and specialised training to feel confident at my level, and would need much more training to carry on learning, but am too old for that, though I still fly an Sback XA42.

After 45 years of flying I still approach such aircrafts trying to fly on a regular basis, using brains and humility. If I were to be able to have a go in a Spitfire, a P51 or Corsair I would never even think of it without highly specialised tuition..

A wise old man, by the name of Mr Auguste Mudry, the creator of the famous french Cap's aerobatic aircrafts, back in 1992 at the Yverdon Switzerland world unlimited aerobatic venue, during one our many conversation over the years ( I was one of his customers) struck me with a brief sentence ;
Aerobatics is to aviation what grammar is to a language and dressage to horse riding. But there is an extatic euphoria when bonding with an aircraft during aerobatics which could extend to airshows or any advanced aircraft flying, where the confidence gained may not be at par with the skill required and the lapse of time available in terms of margin at low level when one makes an error. This will almost always kill you..

I have scared myself more than once over the years, and am trying the learn the lesson.....At some times I guess I have been lucky,
A few years back we had a rash of Mustang accidents here in the states.
I've attached an article I did back then concerning the issues associated with flying the P51 that the forum might find of some interest as it seems associated with the issues being discussed.
Dudley Henriques
9th Dec 2023, 07:21

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Originally Posted by DAHenriques
A few years back we had a rash of Mustang accidents here in the states.
I've attached an article I did back then concerning the issues associated with flying the P51 that the forum might find of some interest as it seems associated with the issues being discussed.
Dudley Henriques
Thank you for this very informative post conveying your experience and sharp analytic capacity to explain these complex phenomenons.

I would kindly ask you whether it would be an option given also the excess power available to take off or go around without applying full power. I.E. on a 6 cylinder lycoming 300HP in an Extra 300 you can easily take off or go around with 2'400 rpm instead of 2'700 and 26 inches of MAP instead of around 29 MAP.

Which makes no sense other than for nose abatement on an Extra, but could help tame those adverse secondary effects of torque and prop on a WW2 fighter. Please post more threads and answers on this forum !
9th Dec 2023, 10:40

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Originally Posted by markkal
Thank you for this very informative post conveying your experience and sharp analytic capacity to explain these complex phenomenons.

I would kindly ask you whether it would be an option given also the excess power available to take off or go around without applying full power. I.E. on a 6 cylinder lycoming 300HP in an Extra 300 you can easily take off or go around with 2'400 rpm instead of 2'700 and 26 inches of MAP instead of around 29 MAP.

Which makes no sense other than for nose abatement on an Extra, but could help tame those adverse secondary effects of torque and prop on a WW2 fighter. Please post more threads and answers on this forum !
Your question is a valid one.
Actually, many of today's civilian operators of Mustangs are already using reduced power on normal takeoffs due to the use of 100LL fuel. It works both ways really. I'm not sure he's the only one but my friend Scott Yoak who owns and flies Quicksilver on our airshow circuit uses the full 61 inches and he uses 100LL fuel.
Basically addressing your question directly, as I always say, nothing connected with flying is written in stone.
The "thing" about handling power in any airplane, and most certainly in something like the Mustang is that the name of that game is control. The prop on a Mustang weighs in at around 450 lbs and strapped onto a V1650-7 Merlin can be a real handful if you get ham handed with the throttle.
We had to deal with the takeoff and go-around issue a while back with the AT6 going supersonic on takeoffs. The question of partial power was front and center. The general consensus at the time was that reducing the power for noise abatement didn't override the obvious advantages involved with altitude gain after takeoff. So most of us just reduced a bit earlier after rotation and smiled a lot and offered free coffee and donuts to the folks living around the field.
A fighter like the Mustang requires a lot of forward thinking when it boils down to things like go-arounds. That's the key really, being one with the airplane.
You simply don't want to allow yourself to fly into a bad situation and misusing power on a go-around falls directly into that category.
The skinny is that instead of thinking of power in a plane like a Mustang it's FAR better to think of power as available through a large range of selection.
So it boils down to common sense. If you have to go around you should be acutely aware of exactly where you are as relates to configuration, available runway ahead, where the power is at that instant......the whole magilla, because if you initiate without having these factors in tow and come in hard and fast from a low power setting to anything around METO or beyond, you could easily end up spoiling your whole day.
So the basic answer to your question is yes. You can certainly select a lower manifold pressure for a go-around.......IF........conditions are favorable for that decision.
It's all a matter of where you are when you initiate and how you are configured. The earlier the better. The deeper you are into the landing in a plane like the Mustang the more careful you have to be with power if needed.
I hope this helps a bit.
Dudley Henriques
9th Dec 2023, 18:59

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Originally Posted by markkal
Thank you for this very informative post conveying your experience and sharp analytic capacity to explain these complex phenomenons.

I would kindly ask you whether it would be an option given also the excess power available to take off or go around without applying full power. I.E. on a 6 cylinder lycoming 300HP in an Extra 300 you can easily take off or go around with 2'400 rpm instead of 2'700 and 26 inches of MAP instead of around 29 MAP.

Which makes no sense other than for nose abatement on an Extra, but could help tame those adverse secondary effects of torque and prop on a WW2 fighter. Please post more threads and answers on this forum !
Addendum: Having read and reread your excellent article on "the issues asssociated with flying the P51" as per your link above answers all of my questions, Worth of note that the issues concerned are certainly common to all taildraggers WW2 fighters; Therefore they have little in common except the tailwheel with those agile and light 300HP+ overresponsive small aerobatic aircrafts;
10th Dec 2023, 03:17

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Thanks for the clarification, (and language lesson)
Made me go back for a look DAR, spelling lesson for me, example from AT6 manual.

10th Dec 2023, 13:20
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That's quite something Megan. 'Spaines why my aviation language is so scattered; raised in Scottish and English heritage, in Canada, with huge American aviation influence!

So, it's a "snap roll"!
10th Dec 2023, 15:49
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Reminds me that when SOCATA first started marketing the TB-10 in the US, a controller cleared a pilot to line up behind the landing To-bar-go. TB-10 pilot acknowledged his taxi instructions and said "by the way, it's pronounced To-bay-go". Another pilot chipped in "so you say Tobaygo, he says Tobargo, let's call the whole thing off..."

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