L-29 crash at Argentine Airshow 12/11/23
Gnome de PPRuNe
Thread Starter
Join Date: Jan 2002
Location: Too close to Croydon for comfort
Age: 60
Posts: 12,635
Received 300 Likes
on
168 Posts
L-29 crash at Argentine Airshow 12/11/23
Join Date: Nov 2006
Location: Down south
Age: 69
Posts: 363
Likes: 0
Received 0 Likes
on
0 Posts
Pilots have very likely missed or failed to compute the "enegy gates" to execute the maneuver. I dont know what they intended to do, if it was a barrel roll ( probably not as they interrupted it while inverted unless they were disoriented or incapacitated) or more likely a reverse cuban 8 ( Pull to 45 degrees up pause then pull through then level off) .
For a normal roll even with the "pause" while inverted would have been a non event, they would have ended up upright though nose low with plenty of height available, they had plenty of energy available after that high speed low pass.
But -and here lies the risk- with this same energy to spare on the reverse cuban 8 after inverted the "energy gate" was busted: way too low and fast. Closing that portion of the loop while inverted was impossible, the radius arc ( It increases at the square of the velocity, double the speed quadruple the radius) was too large and there was not enough room to allow for it other than stall under g while pulling to avoid hitting the ground.
When "energy gates" are not considered in advance, any non compliance or improvisation is a big risk, then the maneuver should be aborted; From inverted complete the half roll and recover straight and level. You may well have luck in a light aerobatic Extra aircraft with his quick roll rate and ligher wing loading, but no chance on a heavy underpowered military jet trainer.
The laws of physics are non negotiable. Speed and height did not permit that closure of the maneuver. It should have been aborted.
There is a similar, very similar incident of an italian eurofighter which hit the sea in the same fashion,in Pratica di Mare some years ago, just google for it.
It was much higher that this L29 probably in excess of 10'000 feet but with much higher closing speed it 3-400 knots I would assume, the radius to close the maneuver was immense, and while pulling out agressively with the sea appraching the Eurofighter stalled under heavy G and pancaked, The L29 likewise stalled dropped a wing and flipped.
More than" fast ship in the wrong hands", fast ship without proper training and improvisation.
that is a bit odd. The control authority is there at all times, they convert a simple upward vector aileron roll into a.... whatever that was. The attitude was never high enough to consider doing a half roll and pull through reversal, part of a cuban, but, then they drop the nose and run out of ideas. The last video segment suggests there may have been a very late short duration stall or it was hesitation by the pilot who was seeing the planet coming up quickly in his windshield. Assuming the pilot had any competency in aerobatics, it is a strange flight path. It isn't G-LOC, and if there was an aileron restriction early on while inverted, that cleared prior to impact, so seems odd, unless a harness/control interference may have occurred. Sad outcome.
Gnome de PPRuNe
Thread Starter
Join Date: Jan 2002
Location: Too close to Croydon for comfort
Age: 60
Posts: 12,635
Received 300 Likes
on
168 Posts
Wouldn't say it's odd, rather just another in a sad litany of low passes and rolls that have seen the nose drop while inverted followed by an unintentional dive with no way out. Most notorious I can recall is the Biggin Hill Invader in 1980.
Hurricane at Shoreham being another.
Moderator
Hurricane at Shoreham being another
The hunter was a slightly different situation, being an unrecovered loop, rather than roll, but similar theme....
DAR, DT2 is referring to a Hurricane crash at the show in 2007, there used to be a video of the event but all I can find now is post crash, occurred during a mock dog fight with a few other participants.
Accident report extract.
Accident report extract.
The Hurricane aircraft, G-HURR, was taking part in a flying display and was following another Hurricane in a tail chase. Both aircraft flew past the spectators along the display line at a height of approximately 200 ft before tracking to the north-west and climbing. The lead Hurricane climbed to approximately 1,100 ft above ground level (agl), pitched nose-up about 45º and rolled to the left through 270º, before pulling into a right turn to rejoin the display line. The second Hurricane, which was approximately 700 ft agl, pitched nose-up about 15º, before rolling to the left. As it reached the inverted position, the roll stopped, the nose dropped and the aircraft entered a steep dive. It struck the ground, fatally injuring the pilot. The aircraft was destroyed by the ground impact and subsequent fire.The pilot appeared to have attempted to follow the manoeuvre flown by the leading pilot. Although the airspeed was adequate, the aircraft had insufficient nose-up pitch attitude at the point of entry to ensure the safe execution of the manoeuvre in the height available. When the aircraft was inverted, the roll stopped, the nose dropped and insufficient height was available to recover from the dive.
Last edited by megan; 15th Nov 2023 at 01:40.
Gnome de PPRuNe
Thread Starter
Join Date: Jan 2002
Location: Too close to Croydon for comfort
Age: 60
Posts: 12,635
Received 300 Likes
on
168 Posts
I was present at the Hurricane accident but didn't see it, but the video clip I saw looked nearly identical to the Firefly crash at Duxford which I did witness. Both aircraft were being flown fairly conservatively.
I used to feel a bit uneasy watching one pilot loop a vintage fighter apparently somewhat slower than Ray Hanna, Brian Smith, et al tended to do. I'm sure he had speed in hand and probably his mostly flatter displays didn't require quite as much energy management as the other exponents did but it still made me look away. Glad to say he and his aeroplanes are still with us, though he no longer flies displays.
I used to feel a bit uneasy watching one pilot loop a vintage fighter apparently somewhat slower than Ray Hanna, Brian Smith, et al tended to do. I'm sure he had speed in hand and probably his mostly flatter displays didn't require quite as much energy management as the other exponents did but it still made me look away. Glad to say he and his aeroplanes are still with us, though he no longer flies displays.
The deadliest airshow crash of all time, 77 killed, including 28 children, 543 injured, 100 0f whom were hospitalised, the two pilots survived with minor injuries.
https://www.youtube.com/watch?v=Oc_LlmW2i0Q
https://www.youtube.com/watch?v=Oc_LlmW2i0Q
The pilots stated that the airbase map they had received differed from the actual layout they found at Sknyliv airfield, where they had been also denied an extra rehearsal flight before the show for financial reasons. Although the root cause of the crash was found into the pilots violating the plan and performing “difficult maneuvers they had not done before”, other factors, including a small flying zone and inappropriate zoning by the show organizers who had allowed spectators to gather so close to the flight line were blamed for the tragedy.
The court found the two pilots and three other military officials guilty of failing to follow orders, negligence, and violating flight rules. Two of the three officials were sentenced to up to six years in prison; the third received up to four years, a military court sentenced pilot Volodymyr Toponar and co-pilot Yuriy Yegorov to fourteen and eight years in prison, respectively.
The court found the two pilots and three other military officials guilty of failing to follow orders, negligence, and violating flight rules. Two of the three officials were sentenced to up to six years in prison; the third received up to four years, a military court sentenced pilot Volodymyr Toponar and co-pilot Yuriy Yegorov to fourteen and eight years in prison, respectively.
Gnome de PPRuNe
Thread Starter
Join Date: Jan 2002
Location: Too close to Croydon for comfort
Age: 60
Posts: 12,635
Received 300 Likes
on
168 Posts
The Biggin Hill Invader crash (pilot plus six passengers) triggered a ban on passengers being carried at air displays - nevertheless I've seen two back seaters die in subsequent accidents whose presence may not have been necessary.
Maybe it would be the right thing to think about what these displays are good for? Showing off by individuals? Scare the crowds? Get spectacular pictures for marketing or news? Show aircraft outside of their normal envelope?
These mostly are veteran aircraft and sometimes veteran pilots, some not with military background and not current like say flight instructors on type. The airframes can be old and fatigued and engines limited or just too precious to risk crashing (well, not an L-29).
From my point of view it would be wiser to limit displays to more moderate manoeuvres like takeoff and landings low flybys fast and slow and some moderate turns. Even during their day many military types had their limits and risks why trigger extreme manoeuvres today when the same frames are worn out and old? Look how Shuttleworth's Edwardians got so old.
Without wanting to spoil the fun but with so many historic aircraft crashing and lost I'd prefer a more moderate style. This should be made a regulation. If not by the authorities then by the insurers. I know somebody privately owning (and keeping) a Mustang and what kind of training and experience the insurance requires before a single pattern.
These mostly are veteran aircraft and sometimes veteran pilots, some not with military background and not current like say flight instructors on type. The airframes can be old and fatigued and engines limited or just too precious to risk crashing (well, not an L-29).
From my point of view it would be wiser to limit displays to more moderate manoeuvres like takeoff and landings low flybys fast and slow and some moderate turns. Even during their day many military types had their limits and risks why trigger extreme manoeuvres today when the same frames are worn out and old? Look how Shuttleworth's Edwardians got so old.
Without wanting to spoil the fun but with so many historic aircraft crashing and lost I'd prefer a more moderate style. This should be made a regulation. If not by the authorities then by the insurers. I know somebody privately owning (and keeping) a Mustang and what kind of training and experience the insurance requires before a single pattern.
Maybe it would be the right thing to think about what these displays are good for? Showing off by individuals? Scare the crowds? Get spectacular pictures for marketing or news? Show aircraft outside of their normal envelope?
These mostly are veteran aircraft and sometimes veteran pilots, some not with military background and not current like say flight instructors on type. The airframes can be old and fatigued and engines limited or just too precious to risk crashing (well, not an L-29).
From my point of view it would be wiser to limit displays to more moderate manoeuvres like takeoff and landings low flybys fast and slow and some moderate turns. Even during their day many military types had their limits and risks why trigger extreme manoeuvres today when the same frames are worn out and old? Look how Shuttleworth's Edwardians got so old.
Without wanting to spoil the fun but with so many historic aircraft crashing and lost I'd prefer a more moderate style. This should be made a regulation. If not by the authorities then by the insurers. I know somebody privately owning (and keeping) a Mustang and what kind of training and experience the insurance requires before a single pattern.
These mostly are veteran aircraft and sometimes veteran pilots, some not with military background and not current like say flight instructors on type. The airframes can be old and fatigued and engines limited or just too precious to risk crashing (well, not an L-29).
From my point of view it would be wiser to limit displays to more moderate manoeuvres like takeoff and landings low flybys fast and slow and some moderate turns. Even during their day many military types had their limits and risks why trigger extreme manoeuvres today when the same frames are worn out and old? Look how Shuttleworth's Edwardians got so old.
Without wanting to spoil the fun but with so many historic aircraft crashing and lost I'd prefer a more moderate style. This should be made a regulation. If not by the authorities then by the insurers. I know somebody privately owning (and keeping) a Mustang and what kind of training and experience the insurance requires before a single pattern.