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-   -   Hawker Hunter Crash at Shoreham Airshow (https://www.pprune.org/military-aviation/566533-hawker-hunter-crash-shoreham-airshow.html)

ORAC 26th Aug 2015 07:41

Looking at the videos and the aircraft recovery it would appear the aircraft operated into its 3 main sections during the first seconds of impact; the tail, main fuselage and wing tanks and the nose section. The nose section being recovered from the far side of the trees towards the airfield. I would speculate that his survival was substantially aided by his slower deceleration through the vegetation and being thrown away from the conflagration caused by the wing and fuselage tank explosions on the road itself.

http://i.telegraph.co.uk/multimedia/...1_3417045b.jpg

http://cache4.asset-cache.net/gc/485...3u%2Bo2A%3D%3D

BEagle 26th Aug 2015 07:45

This is an interesting article:

Shoreham Airshow disaster: Hawker Hunter's final take-off 'unusual' expert says (From The Argus)

The video is here:


It might be completely irrelevant, but worthy of investigation?

Courtney Mil 26th Aug 2015 09:04

Wingswinger,

Thank you for responding. Regarding use of flaps in the Hunter, I agree with the point you made at your last post. BEagle has commented on this quite succinctly - he has an uncanny memory of technical and handling information of pretty much everything he's flown; lots of good stuff in his head about Hunter and Gnat. He deals specifically with formation aeros here:


Originally Posted by BEgle
If I recall correctly, use of 23 flap in ACM caused an initial nose-down trim change, which in the environment of dynamic ACM was easily overcome by a firm elevator movement. The effect of 23 flap gave an increased turn rate, which was advantageous in getting to a sight-on solution, but the increased drag meant that it was only a temporary advantage?

Whereas flying certain manoeuvres with 23 flap was entirely normal for formation aerobatic teams.

As in...

http://www.fradu-hunters.co.uk/fradu...es/fprm306.jpg
FRADU

He also remarked on the use of flap in solo aeros here:


Originally Posted by BEgle
Use of 23° flap in the Hunter whilst manoeuvring was quite common when I was taught ACM at Brawdy - just don't leave any flap down above M0.9 or you won't recover. Not relevant here though...

I think we used 320 KIAS and 23° flap for low speed loops - apart from my chum Ozzie who misheard the brief and tried 230 KIAS....once.

Here's a Sweedish Air Force Hunter (photo by Alan Kenny) taken at the Jersey Air Show in 2013 - posted as a link as the image is too big for PPRuNe: http://www.airforcesmonthly.com/cent...llery/7474.jpg which just about shows the use of a notch or two in a solo display. My point being that use of flap in aeros has been standard practice in some cases for a long time.

G-loc: you are absolutely right about both delayed onset and physiological factors affecting g tolerance, but I would not wish to comment on the latter here as that could mean too much fuel for the blame-the-pilot brigade (hopefully not PPRuNe posters, but the lurkers that read this - I think we hit around 1,000 people viewing for the past few days!).

From my wonderful few days doing the USAF's g training and riding their centrifuge I recall a couple of relevant points. Most people's resting g tolerance seems to be around 4 g (with considerable variation) and onset of symptoms above or around that are generally limited to peripheral dimming followed by greying. At higher g levels (8 plus for most) without effective straining the effects are likely to be seven seconds of consciousness (due to oxygen stored in the brain) followed by rapid blackout. There is, of course, an in-between. The rapid, insidious onset is not normally a factor in aeros - but as you stated and demonstrated by personal experience, there are exceptions. I would add that variations with age do not appear to be particularly significant, although I don't recall the age band their research covered.

Robert Marks 26th Aug 2015 09:21

I've been watching the videos that surfaced after the crash with great interest, and my opinion poor decision making is the main factor of this accident, for reasons I will describe below.

The following is worth noting about the Reverse ½ Cuban 8 maneuver:
The Reverse ½ Cuban 8 maneuver is used as an end turn-around maneuver, and may be offset well to the left or right for this purpose.

** This is important, because the same is visible in the video referenced below.

To begin with, the airplane is seen in this video to approach A27 from the North, doing a low level left hand turn, which it finished on an approximate South-Eastern heading, roughly above the Cuckoo's Corner (Coombes Rd).
At that point from what is visible in the video, he was flying roughly around 100 feet AGL, at which altitude, he began a Reverse ½ Cuban 8, which when he started he was flying roughly parallel to A27 as seen in this video.

** This is important because starting that evolution parallel to the highway, also implies the possibility of it ending parallel to the highway (or directly above it), which it did.

Low level flying coupled with poor situational awareness amount to a poorly judged evolution with equivalent results, for reasons described below:

For what it's worth, I think any display pilots of highly maneuverable planes (such as Eurofighter, Rafale etc) would be reluctant if asked to start a Reverse ½ Cuban 8 at that altitude. Simply because it's a dangerous proposition, regardless of the airplane you are flying. Even if done right, it implies you would also finish the maneuver very close to ground level. Which is not a way to do things generally, let alone at an airshow, and much less in a vintage aircraft, equipped with a turbojet engine which even under perfectly functioning conditions, is likely to have a longer spool up time (like the L-39 does) and you will waste precious seconds close to ground level waiting for that power to be delivered to an otherwise not very energy-efficient air frame.

It is then wise, to allocate an altitude buffer for maneuvers such as Loops, Split S, or Reverse ½ Cuban 8.

Whether there was an unusual takeoff in a lower power setting than usual, or the usage of flaps influenced the elevator authority can be debated until the technical investigation is finalized. If the airplane didn't deliver enough power upon taking off, and the pilot was aware of the limitation, that means he had even less reasons to attempt that maneuver in the first place.

I believe if the pilot would have decided to go for a ½ Cuban 8, instead of Reverse ½ Cuban 8, the evolution would have ended at a relatively safe altitude and we wouldn't be having this conversation today.

Voicemail 26th Aug 2015 09:40


Originally Posted by BEagle (Post 9095335)
This is an interesting article:

Shoreham Airshow disaster: Hawker Hunter's final take-off 'unusual' expert says (From The Argus)

The video is here:


It might be completely irrelevant, but worthy of investigation?

Anyone flown a Hunter from Weald? Is this an "oddly flat" departure or just hot day and fuel in the underwings?

BEagle 26th Aug 2015 09:51

Mr Hatcher stated:

'Every display pilot knows the minimum display height is 500ft -that's the height he should have come in at and didn't. So he broke the rules there.’
As one who has only flown aeros for personal enjoyment at 'HASELL height' and above*, rather than in displays, I'm not qualified to comment on Mr. Hatcher's comments regarding minimum height criteria. But surely they form part of the pilot's DA? Does a DA include 'Rule 5' exemption?

PS - Thanks for your kind comments, Courtney Mil. Usual fee....;)??


*Although I did win the Bulldog aeros pot on my CFS course - unfortunately the other chap, who probably should have won, overstressed during his manoeuvre, so that was that. But the rest of the course must have been pretty cr@p as I was distinctly 'average'!

Above The Clouds 26th Aug 2015 10:39


BEagle
It might be completely irrelevant, but worthy of investigation?
Does anyone know when this particular T7 airframe was released from HMS ?

nipva 26th Aug 2015 10:41

T7 Anti-g system
 
Despite many hundreds of hours on Hunters I cannot recall if the T7's anti-g supply is the same as the single-seaters i.e. an accumulator or if it is supplied with bleed air. I do recall that it was quite disconcerting on a range sortie to suddenly run out of anti-g usually on pulling off the target.

My apologies if this has already been covered

AtomKraft 26th Aug 2015 10:51

WV372 was built as an F.4 in 1955.
Converted into a T.7 in 1959
Flew as a civilian a/c in 1998.

Courtney Mil 26th Aug 2015 11:02


Originally Posted by nipva
Despite many hundreds of hours on Hunters I cannot recall if the T7's anti-g supply is the same as the single-seaters i.e. an accumulator or if it is supplied with bleed air. I do recall that it was quite disconcerting on a range sortie to suddenly run out of anti-g usually on pulling off the target.

My apologies if this has already been covered

It has been. Post320. Here you go.


Originally Posted by BEgle
The Hunter 7 has a gaseous anti-g system; if that fails unexpectedly you might well grey out. But it's a pretty reliable system and the +g available in the accident manoeuvre would seem to have been less than would cause the pilot to lose consciousness if the anti-g system failed.


bigglesbrother 26th Aug 2015 11:06

Looping the Hawker Hunter
 
Attached are links to videos showing 22 RAF Hawker Hunter aircraft looping in close formation at world famous airshows.

So why in 2015 is a single Hunter unable to loop successfully and safely at an airshow?


https://en.wikipedia.org/wiki/World_record_loop

Black Arrows - CXI (F) Squadron

https://www.youtube.com/watch?v=Uwn9DSG6Hvo

Above The Clouds 26th Aug 2015 11:09


bigglesbrother
So why in 2015 is a single Hunter unable to loop successfully and safely at an airshow?
I do believe that is precisely what the Uk AAIB are trying to determine. :rolleyes:

Courtney Mil 26th Aug 2015 11:16

Well said, ATC. And it wasn't a loop.

ZeBedie 26th Aug 2015 11:20


There's another one at it now on the Telegraph, saying the takeoff looked unusual because he used a lot of runway
But to be fair, it did appear to have a long ground roll - in excess of 30 seconds, I think. An improvised reduced power T/O?

Courtney Mil 26th Aug 2015 11:28

Hardly standard practice. I wonder how anyone would calculate take off data at an intermediate power setting. Anyone here have a Hunter ODM handy?

oggers 26th Aug 2015 11:53

Athonite:


I suggest you read some of James Reason's books. Pilot error is a thing of the past.
Well if you read it in a book it can't possibly be the claptrap that I think it is.

ZeBedie 26th Aug 2015 12:25

North Weald 02 is only 6200'. I think there was no headwind component, a hot day.

Above The Clouds 26th Aug 2015 12:31


ZeBedie
North Weald 02 is only 6200'. I think there was no headwind component, a hot day.
TOD MAUW would have been in the region of 4000ft.

45-25-25 26th Aug 2015 12:53

Take-off Distances
 
From my Pilot's Notes (last amended in 1972!) with Zero Wind and +15 the Ground Run with 2 x 100 gallon drop tanks is given as 950 yards and +30 it is given as 1120 yards. There are no figures for a reduced power Take-off.

Above The Clouds 26th Aug 2015 13:31

Since starting the thread I have avoided inputs of a speculative nature to a possible cause for this tragic event and I really don't want to now, other than put some thoughts out there for others with more experience working on and flying the Hunter.

For the engineers out there if I say "Gundip" system and this particular airframes form 700 would you understand where I am coming from and what system was affected, the required "mod" residual wiring, due to spurious inputs into a particular system.

When WV372 was in HMS she was converted to a T7 then had periods of long term storage before coming in to civilian operation, did the complete "mod" get done before leaving HMS.

Now a video showing what seems to be an extended take-off run from North Weald departing for Shoreham, and that is all it shows, but refer to the "mod" again.

Discussions and statements of possibility not making the entry altitude/height for manoeuvre recovery and the unusual shape of the manoeuvre during both vertical phases, but refer to the "mod" again.

Also bear in mind the picture I posted and what I said earlier in post 38 and taking the above points into the equation.

No speculation just comments to provoke a thought process for those who understand the aircraft in depth.


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