Crash at Shoreham Air show

[hidetheelephants]

angrymoby said:

https://www.youtube.com/watch?v=PeSpNNxcVEg

*if* this vid hasn't been tampered with, this looks like it's shot from the north embankment of the Adur & shot from approx 500-600m away ...so roughly a 1.5-2s second sound delay ...so that noticeable drop in engine noise at 0:58 (where it hits the deck) ...is actually the audio from around 0:56

I think he lost all power around that point, so...

Whatever is there is far more likely to be artifacts of a crappy digicam mike than a faithful reproduction of an engine problem; for what it's worth all I can hear is some doppler and then the engine noise being muffled, presumably as it dropped below the treeline.

[MitchT]

angrymoby said:

https://www.youtube.com/watch?v=PeSpNNxcVEg

*if* this vid hasn't been tampered with, this looks like it's shot from the north embankment of the Adur & shot from approx 500-600m away ...so roughly a 1.5-2s second sound delay ...so that noticeable drop in engine noise at 0:58 (where it hits the deck) ...is actually the audio from around 0:56

I think he lost all power around that point, so...

that would mean around 0:34s in this one:

https://www.youtube.com/watch?v=pvHplYmh2f8

Could the drop in engine noise to be due to the trees masking it as the plane drops behind them? I know from attending F1 races that the reduction in volume when a loud machine disappears behind an object that you wouldn't credit with the ability to block out huge amounts of noise can actually be quite considerable.

ETA: Started typing before 'hidetheelephants' posted similar.

[Le TVR]

It all looks quite relaxed and nominal throughout except the final segment of the pull up where in the last seconds he seems to be pulling far far more. Probably having just realised where the eventual base height was going to be. It looks to me as though that final pull caused the aircraft to depart, possibly an elevated G stall and it pancaked onto the road. What sequence of events led up to that eventual base height remains to be established.

Disclaimer: I am not an aerobatic pilot this could be bovine excrement.

[Eric Mc]

Based on watching thousands of flying displays over the decades and many, many looping manoeuvers, it does seem to me that the height achieved at the top of the loop was a bit on the low side and that the circle described by the loop was almost destined to intercept the ground.
That extreme nose up attitude seen in the last second or so is not, to me, part of a normal exit from a loop manoeuver but more a last second, desperate attempt by the pilot to initiate a pull out before he impacts the ground.

The sink rate was such that even if an extreme pull up was initiated it wasn't going to prevent a ground impact.

As for the apparent reduction in noise, I don't particular see that as anything indicating a loss of power but more just the normal variation you sometimes get as an aircraft manoeuvers.

[angrymoby]

MitchT said:

Could the drop in engine noise to be due to the trees masking it as the plane drops behind them? I know from attending F1 races that the reduction in volume when a loud machine disappears behind an object that you wouldn't credit with the ability to block out huge amounts of noise can actually be quite considerable.

ETA: Started typing before 'hidetheelephants' posted similar.

you both could be correct, but that mic has picked up the previous 0:55s no problem ...& yes, the noise would drop behind the treeline, but even without any delay to sound (which there would be) that video suggests it's dropped before it's even got to them

Edited by angrymoby on Thursday 27th August 18:48

[TTmonkey]

Eric Mc said:

Based on watching thousands of flying displays over the decades and many, many looping manoeuvers, it does seem to me that the height achieved at the top of the loop was a bit on the low side and that the circle described by the loop was almost destined to intercept the ground.
That extreme nose up attitude seen in the last second or so is not, to me, part of a normal exit from a loop manoeuver but more a last second, desperate attempt by the pilot to initiate a pull out before he impacts the ground.

The sink rate was such that even if an extreme pull up was initiated it wasn't going to prevent a ground impact.

As for the apparent reduction in noise, I don't particular see that as anything indicating a loss of power but more just the normal variation you sometimes get as an aircraft manoeuvers.

From your experience in watching such displays, and from the video of the event, do you think his approach (height/speed) was what you would normally expect?

It's very hard to tell I know, but it looks 'sluggish' to me. But then we know how it ends, so perhaps that's just how you see it knowing this.

[Eric Mc]

As you say, hard to tell. It might be worthwhile comparing the video of the accident with the good quality video of the same aircraft's display at last year's Shoreham Air Show.

I wonder if the AAIB will be able run a split screen comparison in a similar way to what they do when comparing driver lap times in F1 TV coverage?

[Simpo Two]

It seemed to me that during the last section of the loop, say from 40 degrees nose down, there was a period where the aircraft, instead of starting to level out as you'd expect, continued down in a straight line. Maybe it was an illusion but that's how it looked, and if so, that's where crtitical height was lost.

[saaby93]

Simpo Two said:

It seemed to me that during the last section of the loop, say from 40 degrees nose down, there was a period where the aircraft, instead of starting to level out as you'd expect, continued down in a straight line. Maybe it was an illusion but that's how it looked, and if so, that's where crtitical height was lost.

Me too
Tell me I'm wrong but to me the loop manoeuvre was complete. He'd come out of it but very low and was into the cross country phase. What happened next was a lack of power or height (both) resulting in him dropping it (or it dropping) onto the road

[Mave]

saaby93 said:

Me too
Tell me I'm wrong but to me the loop manoeuvre was complete. He'd come out of it but very low and was into the cross country phase. What happened next was a lack of power or height (both) resulting in him dropping it (or it dropping) onto the road

I don't think he ever completed the loop. I think he was still going down, too low, and the change in attitude towards the end was a last effort to slow the rate of decent but he couldn't pull enough alpha and it stalled. A bit like going around a corner too fast, grabbing an armful extra lock and doing a 4 wheel drift off the road :-(

[9mm]

Mave said:

saaby93 said:

Me too
Tell me I'm wrong but to me the loop manoeuvre was complete. He'd come out of it but very low and was into the cross country phase. What happened next was a lack of power or height (both) resulting in him dropping it (or it dropping) onto the road

I don't think he ever completed the loop. I think he was still going down, too low, and the change in attitude towards the end was a last effort to slow the rate of decent but he couldn't pull enough alpha and it stalled. A bit like going around a corner too fast, grabbing an armful extra lock and doing a 4 wheel drift off the road :-(

That's what is looks likes to me too. The bottom of the loop, had he made it, would have been 50m (notional figure) below the surface of the road. Instead he went in like a long jumper landing.

[HoHoHo]

Mave said:

saaby93 said:

Me too
Tell me I'm wrong but to me the loop manoeuvre was complete. He'd come out of it but very low and was into the cross country phase. What happened next was a lack of power or height (both) resulting in him dropping it (or it dropping) onto the road

I don't think he ever completed the loop. I think he was still going down, too low, and the change in attitude towards the end was a last effort to slow the rate of decent but he couldn't pull enough alpha and it stalled. A bit like going around a corner too fast, grabbing an armful extra lock and doing a 4 wheel drift off the road :-(

So would it be fair to say the little wobble prior to hitting the ground wasn't an effort to try and alter his course, it was the aircraft in the stall and literally falling out of the sky with wings doing what I've seen models do just before it goes in?

[saaby93]

yes youre right it still had too much downward momentum, the plane didnt have enough forward motion to counter it and eventually stalled

This one at 0.25 speed shows it

https://www.youtube.com/watch?v=pvHplYmh2f8&fe...

Its the pulling out of the downward piece that seems to take too long
and theres the loss of height going over the top
and
the whole thing doesnt look right

[Mave]

HoHoHo said:

So would it be fair to say the little wobble prior to hitting the ground wasn't an effort to try and alter his course, it was the aircraft in the stall and literally falling out of the sky with wings doing what I've seen models do just before it goes in?

I'm obviously speculating just like others but yes, to me it looked like it was buffet as the wing stalled - on the far side of the CL alpha curve - in a max and decreasing lift, high drag state.

[RoverP6B]

Referring back to comments on the takeoff, from the video (comparing with Google satellite images of North Weald) it appears that he took off on runway 02, and the few reports I've been able to find indicate a 7-15kt southeasterly wind - so taking off with a slight tail/crosswind, but not enough that you'd think a Hunter would notice. Admittedly it was weighed down with fuel, but one slightly odd thing is the visible nosewheel bounce as the aircraft passes the camera, as if the pilot was trying to haul it off before the wing was ready. Any more expert views than mine on this?

[jamieduff1981]

RYH64E said:

TTmonkey said:

Were any of them attempting to recover from a loop at 500ft? No? What a daft thing to say mate.

The issue is not whether he could do it in this plane, the issue would be was he trying to do this at 80-100mteres lower than is possible/he realises....?

Another 50m of height and we may not of ever been having this kind of conversation would we, in all likely hood. I think he almost recovered the plane, it was flying and was flyable, and I've seen no real evidence of a mechanical failure being the cause yet. No bang, no smoke, no flames before impact.

so perhaps he has misheard ATC telling him the QFE figures, or perhaps dialled them in wrong?

He seemed to run out of sky to fly in, as he seemed to be too low to pull out of the recovery.

Would you expect such a manoeuvre to operate to such tight limits that a change in weather could lead to a catastrophic accident?

In all honesty, yes. The speed at which these aircraft cover distance is such that the wrong density altitude and barometric pressure adjustment on the altimeter would put you far enough out to cause an issue. It has happened before (without consequence to those on the ground). I'm not saying that's what I believe the cause was here, but it is a very real issue pilots need to be aware of.

I've never displayed but do have some hours of aerobatics from various joyrides.

If you're nice and high up and don't need to worry about the ground, and in a low powered plane you would initiate a quarter clover from a fast straight and level, pull the nose up to your intended pitch and watch the speed bleed off. You have to roll it inverted and pull through the horizontal before running out of airspeed. How quickly you reach the speed you have to roll it over at depends on your power (which is degraded with higher ambient temperature and density altitudes) and the steepness of your climb. In a jet like the Hunter (and I am speculating a bit here) I'd expect the pilot would be doing that but looking to achieve a gate altitude prior to reaching his minimum airspeed.

The base heights for civil displays are quite low - so the spectators can seen the aeroplane against a moving background. Too slow over the top means going downwards for longer. Too low over the top means a couple of hundred feet of sky you expect to have below you isn't there.

Once again I'm not saying this is what happened at Shoreham. All I'm saying is that the relevant instrumentation works by measuring the atmosphere and interpreting those measurements on a visual display which the pilot then interprets further. Mal-adjusted measurments can lead to misunderstandings of one's situation.



There's a Hunter documentary on Youtube. In it is an interview with a now-elderly test pilot who arrived to demonstrate the aircraft in Europe (Switzerland I think) and started the display by spinning the aircraft to a pre-determined height then initiate recovery to pass low over the airfield. Upon counting the turns in the spin, reaching his gate height and recovering the aircraft he found himself diving vertically at the local landscape with the fields much bigger in the windscreen than he expected. He hadn't set the altimeter to QFE before starting the display...

[saaby93]

For anyone confused about QNH QFE
https://www.youtube.com/watch?v=12kpSywMph4
Read the comments too

A (much) slower version
https://www.youtube.com/watch?v=7ijKdzjldV0

Temperature at 25 mins

Edited by saaby93 on Friday 28th August 09:24

[SMB]

Well the AAIB have now asked for my hi-res pictures following my email to them and Sussex Police earlier.
These have duly been sent and I hope they help the investigation team.

[KTF]

pprune said:

AAIB & Police appeal for Shoreham video or stills
Two requests:

1) If you witnessed the accident at the Shoreham airshow on Saturday 22 August 2015 you may contact the AAIB using our [e-mail] email address.

We are particularly interested in any photos and videos that you may have taken showing the accident.

---

2) Anybody with pictures or video of Saturday's crash is asked to contact Sussex Police via this dedicated e-mail please.

[e-mail]

JUST PROVIDE A NAME AND CONTACT NUMBER, DO NOT ATTACH THE FOOTAGE.

[tonyvid]

jamieduff1981 said:

There's a Hunter documentary on Youtube. In it is an interview with a now-elderly test pilot who arrived to demonstrate the aircraft in Europe (Switzerland I think) and started the display by spinning the aircraft to a pre-determined height then initiate recovery to pass low over the airfield. Upon counting the turns in the spin, reaching his gate height and recovering the aircraft he found himself diving vertically at the local landscape with the fields much bigger in the windscreen than he expected. He hadn't set the altimeter to QFE before starting the display...

I went to a RAeS lecture by a Hunter test pilot and he described just this, seems the audience were suitably impressed by the performance and ensuing low pass after the manoeuvre - only he knew how close it was... Fascinating guy who talked about a fascinating aircraft that had some nasty habits so pilots were not permitted to do some certain maneouvers in service. None really applies to what happened this time though.