Aerobatics question
Discussion
I've been reading about the P63 crash at Biggin Hill a few years ago. Looking at the video and reading the accident report the pilot appears to have headed into a loop but very slowly and steeply, almost more like an almost vertical climb. Then ran out of speed at the top and span out of control.
If a pilot is going into a loop and realises during the climb that they aren't going to have enough speed, what options are there?
Warning - fatal accident.
https://www.youtube.com/watch?v=_jSHZPmiSPk
If a pilot is going into a loop and realises during the climb that they aren't going to have enough speed, what options are there?
Warning - fatal accident.
https://www.youtube.com/watch?v=_jSHZPmiSPk
There aren't really any options if your nose is pointing upwards and you lack energy to level off in a controlled manner. Well, there are, but they will all leave you at a lower altitude than you started the aborted loop - which is the age-old gotcha with mistakes during airshow aerobatics.
You're basically going to stall turn, tailslide or just flop your way over. You will pitch or yaw your nose back vertically downwards. If you don't force on of these methods, the aeroplane will select one for you.
You're basically going to stall turn, tailslide or just flop your way over. You will pitch or yaw your nose back vertically downwards. If you don't force on of these methods, the aeroplane will select one for you.
Presumably if he'd realised in time a stall turn wouldn't have lost him too much altitude? But once he's past the vertical I guess it's too late. Very experience pilot but looks like he just got it wrong on the day
http://www.aaib.gov.uk/cms_resources.cfm?file=/dft...
http://www.aaib.gov.uk/cms_resources.cfm?file=/dft...
With something like a Sukhoi 26 or 31, an Extra or an Edge 540 you might have more options when your wing can deliver a lot of lift, you have little pitch and yaw inertia and you have massive control surfaces with all 3 axis wetted with slipstream. These aeroplanes are designed to have huge control authority down to non-existant airspeeds using propwash.
Something like a P63 is a high speed gun platform and is well outwith its flight envelope going so slow. You rely on propwash for any control authority if you've made such a mistake as above even if you have recognised it, and the aeroplane will roll with the engine torque whether you like it or not. Going so slow, that great big propeller starts to have a big say in which way you're pointing thanks to gyroscopic precession. Intentional pitch causes unintentional yaw and vice versa.
It all conspires to leave you pointing in a different direction to that which you're actually going. At worst you part control completely and at best you waste precious height straightening up before you can think about pulling on G to level out. With airshow mistakes you're usually too low to get away with it - hence the old advice to start manouvers "3 mistakes high" or whatever.
Bancroft-Wilson was a great airshow pilot and whenever I saw him display he was always very methodical and precise. I don't suppose anyone really knows what happened at Biggin Hill that day. It just started off badly for him and went downhill from there. There were 3 crashes at that airshow, 2 of them fatal. This accident was the second fatal and the airshow was terminated.
Something like a P63 is a high speed gun platform and is well outwith its flight envelope going so slow. You rely on propwash for any control authority if you've made such a mistake as above even if you have recognised it, and the aeroplane will roll with the engine torque whether you like it or not. Going so slow, that great big propeller starts to have a big say in which way you're pointing thanks to gyroscopic precession. Intentional pitch causes unintentional yaw and vice versa.
It all conspires to leave you pointing in a different direction to that which you're actually going. At worst you part control completely and at best you waste precious height straightening up before you can think about pulling on G to level out. With airshow mistakes you're usually too low to get away with it - hence the old advice to start manouvers "3 mistakes high" or whatever.
Bancroft-Wilson was a great airshow pilot and whenever I saw him display he was always very methodical and precise. I don't suppose anyone really knows what happened at Biggin Hill that day. It just started off badly for him and went downhill from there. There were 3 crashes at that airshow, 2 of them fatal. This accident was the second fatal and the airshow was terminated.
Simpo Two said:
He was one of the better-known of my school alumni. IIRC the ailerons jammed/failed; he must have known at the top it wasn't going to end well.
I don't recall any identified defects in the report from the investigation.The various videos showed him hold in full up elevator then add a bootfull of rudder at the top. Maybe he knew he'd screwed up and tried to half-flick-roll it erect? Maybe he just got it even more wrong. I hold the man in very high esteem but all evidence suggests an error. He had a partial loss of control earlier in the display. Each pass got slower and slower with engine RPM higher and higher. He was bleeding off speed with every manouver.
IIRC the minimum entry speed for a loop in the P63 was 250kts. He was calculated using the video panning to be doing around 190kts when he pulled up in to the last manouver.
People naturally want to blame the machine. I'm the son of an aircraft maintenance engineer who was implicated in a fatal crash. He was not at fault, the drawn out investigation instead laying the blame on the design engineers, but the mental trauma on those working with aircraft on the ground when everyone points fingers at the aeroplane is very real.
I'm not having a pop - just pointing out that there are very few accidents whereby nobody pays a price. The machine isn't a non-entity - someone somewhere feels responsible for the accident.
Recognising it's going wrong early and pushing to unload the wing when running out of energy and approaching critical angle-of-attack is the key. The wing doesn't need to provide any lift if the aircraft is unloaded to zero-g and the aircraft can be flown out well below the '1g' stall speed as long as there is enough airflow for control effectiveness. If the aircraft does run out of energy at or past the vertical as in the accident video then centralising stick and rudder will stop any further incipient spin and the aircraft will eventually tent-peg straight down allowing recovery to level flight if there's enough height...
IIRC Guy Bancroft-Wilson mis-handled the aeroplane at Biggin, haven't heard any mention of control restriction either.
IIRC Guy Bancroft-Wilson mis-handled the aeroplane at Biggin, haven't heard any mention of control restriction either.
By many first hand accounts, when in service the P-63 was prone to flat spins possibly due to the centrally mounted engine and it's effect on polar moment of inertia. Judging by the number of warbird accidents at airshows over the years, and the type of those accidents, I guess it's no real surprise that a P-63 was lost in that way.
Dr Jekyll said:
I'm sure it was a Vampire in wake turbulence from the Vixen. The same team had a Venom which suffered a landing accident arriving at the show.
Correct. The 3 de Havilland jets were supposed to display together in Vic formation. The Venom landed wheels-up on arrival at Biggin Hill. The Sea Vixen and Vampire displayed as a 2 ship instead. IIRC they flew line astern, which exposed the Vampire to the wake turbulence from the much larger and heavier Sea Vixen.Dr Jekyll said:
I've been reading about the P63 crash at Biggin Hill a few years ago. Looking at the video and reading the accident report the pilot appears to have headed into a loop but very slowly and steeply, almost more like an almost vertical climb. Then ran out of speed at the top and span out of control.
If a pilot is going into a loop and realises during the climb that they aren't going to have enough speed, what options are there?
Warning - fatal accident.
https://www.youtube.com/watch?v=_jSHZPmiSPk
I saw a Spitfire at Woodford crash in a very similar scenario. Very upsetting to see close up.If a pilot is going into a loop and realises during the climb that they aren't going to have enough speed, what options are there?
Warning - fatal accident.
https://www.youtube.com/watch?v=_jSHZPmiSPk
Mabbs9 said:
I saw a Spitfire at Woodford crash in a very similar scenario. Very upsetting to see close up.
The interesting thing about the Woodford Spitfire is that it did appear to be completing the loop OK until it became apparent that it was too low to pull out, it didn't fall out of the top of the loop. Whether it had that little bit more speed or it was something to do with the flying characteristics of the Spitfire as opposed to the P63 I don't know.There was also the Thunderbird F16 crash that superficially looked exactly the same as the Woodford Spitfire crash but turned out to be nothing to do with speed but with the pilot getting confused as to altitude.
It happens time and again during display flying: high rate of descent vs sufficient/available pitch-rate/angle of attack required to miss the ground. Re: the Spit & Thunderbirds F16 above, loads of pilots have been in the same situation. Houses getting bigger uncomfortably quickly: pull too hard and you're past critical angle-of-attack, stall, impact, kablooey, pull to available max pitch-rate, still not enough, impact etc. Either way, too much vertical feet per minute and not enough height and you're screwed unless there's a yellow & black handle in the seat.
Typhoon display pilot almost piled-in practising at RIAT a few years ago, Tucano display pilot smacked the ground at Linton during practice in similar circumstances.
Typhoon display pilot almost piled-in practising at RIAT a few years ago, Tucano display pilot smacked the ground at Linton during practice in similar circumstances.
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