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

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?

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:

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:

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.

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.

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

Mr Hatcher stated: 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'!

Does anyone know when this particular T7 airframe was released from HMS ?

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

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

It has been. Post320. Here you go.

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

I do believe that is precisely what the Uk AAIB are trying to determine. :rolleyes:

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

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?

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

Athonite:

Well if you read it in a book it can't possibly be the claptrap that I think it is.

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.

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.

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.

And it wasn't a loop..... So what was it meant to be?
 

A reply to Courtney Mil post #432

You said in your post #432 ...... "And it wasn't a loop".

Well, from the many video links on pprune we can see that the T7 Hunter entered from a level left turn, started fast very low down, went up as if to loop, slowed at the top as is usual .... and then descended initially – but sadly unsuccessfully - as if to complete a loop.

So what was the intended vertical manoeuvre in your words please?

Please allow me to help CM out here.

A loop is conducted entirely wings level - from initial pull-up, through the vertical, the inverted and the pull-out, which means you start and finish on the same heading (or as close to it as most of us can manage). It is the most basic of aerobatic manoeuvres, which is why it is normally the first aerobatic taught to students.

A manoeuvre where you pull to the vertical, roll through 90 degrees and then complete a 3/4 loop to exit at 90 degrees from entry is called a quarter clover. It is very useful for positioning during displays.

It appears that the intended manoeuvre on this occasion was a quarter clover, or a modified version of same as the heading change was less than 90 degrees. However, only one person knows exactly what the intended manoeuvre was, and he is currently unable to tell us because he is still in an induced coma.

I hope this helps your understanding.

Quarter clover. The roll on the way up. See post 378, thought to be his sequence does not include a loop.

Edit to add: Thanks, Fortissimo. Beat me to it.

Voicemail #416 and BEagle #403:

The video of the takeoff at North Weald shows quite a brisk cross wind (see the paper bags blowing past) which could even be tending to a quartering tailwind.

No wonder the takeoff is flat.

First post so gentle please. Fast jet retired, flown the Hunter and done some display flying.

My problem is that Im on holiday in Germany, arrived day of crash, and can't get my IPad to play videos. Read all the experts and frankly confused. What did he do? Was it a quarter clover or did he just do a loop to the "left". One would probably be deliberate the other could signify he had a problem. Either way if He missed gate ht or speed he was heading to bust base ht - which he obviously did. I'm struggling with how such an experienced pilot could miss such an important gate.

However, the pilot of the 88 Abingdon F4 loop into the ground was one of mine at Valley and never worried me. Don't know anybody who hasn't bust base ht when it's been 5000 ft by thinking "never mind that was nearly gate ht" but not when doing LL aeros, its an automatic roll off the top and foxtrot Oscar.

Gratefull for any descriptions.

Above The Clouds, after the loss of 216's T7 XL597, the RAF deleted all gundip components from Hunter T7 aircraft.

That was 1980; WV372 served with the RAF until being transferred to the RN in 1984. It subsequently flew with FRADU until 1993, so it certainly should have had all gundip components removed.

Regardless of this accident can you also explain the potential errors and their consequences in this type of manoeuvre? Just for the clarity of those reading the board.

You might think that.... but history proves that not to be the case. Hawk Trainer accident with company test pilot is at least one display accident that fits the same story.

Odanrot,

Welcome. A brief précis of one of the videos, caveated that this is what it looked like from that particular angle. We do not know how level the camera was held so I can't be sure of angles.

Andy was seen to run in at low level and pulled up into what concensus here believes to have been a quarter clover. It did not look like he achieved the true vertical, but not by much. He rolls through probably slightly less than 90 degrees and continues to pull over the top. No one here can judge if he made the gate height or not, so I wouldn't assume that.

The pull appears to slacken slightly on the way down and the last quarter it looks like he's pulling hard, possibly very hard. Just before impact on the A27 the aircraft is about ten degrees nose up but still descending. There is a hint of what may be wing rock shortly before impact.

On impact there is a large fireball and it looks like the cockpit section detaches from the fuselage and remains slightly ahead of the majority of the fire. I could not see an ejection gun so a complete ejection sequence is also unlikely.

Any corrections welcome.

There is no evidence to indicate that he did not meet his parameters at the top and it looked like there was hot air coming from the jet pipe in the final stages, so the engine was doing something - quite what, I could not say, but possibly working.

Andy was recovered from the scene very badly injured and is currently alive, but in a medically-induced coma. There has been very little news since about his condition. Wreckage is still being recovered from the scene and there were a number of casualties and fatalities among people in cars, one or more motorcyclists and people on foot or sitting (I think) in the area.

There has been a lot of speculation about the causes and the safety of a display in that area. Until evidence other than photographs, videos and witness becomes available further comment on my behalf would not be appropriate.

Hope that kind of brings you up to speed. I assume you will have seen the news paper articles and some of the (in my opinion) slanderous statements that have appeared in the media by so called experts.

ATC, Beagle. What's gundip?

Probably not if it's likely to feed further speculation.

My first assesment concerning the maneuver flown was, that it was a 1/4 of a clover leaf. After looking at the published graphs with the probable flightpath on this thread and the ongoing discusssion I offer another version for discussion. I asked myself, what kind of maneuver would I do at that point, and came up with neither a loop nor a 1/4 Clover leaf, I would have done just a low pass along the line. But the task might have been not to cross the A27 at that low altitude, requiring a pullup followed by a descent and some small heading change. I would have done a Barrel Roll type maneuver there, but never a 1/4 Clover Leaf.

I watched some videos from former displays of A.H. in the hunter and Jet Provost on youtube, all available on a google search, and observed most repositionings were performed by some Barrel Roll type maneuvers. I found none pure Clover leaf type maneuver, but that might also be due to the fact, that the top of such maneuver is the point farthest away from the action and thus not recorded or edited out of the clip.

In the assumed flightpath the Jet comes in low and fast, turns somewhat to the right and pulls up, like the initial part of a Barrel Roll to the left. At that point prior pullup the airfield might be hidden behind the tree line. For a Barrel Roll type positioning the turn to the pullup point was too late, which the pilot might have recognized during the pullup. In order to reduce the forward travel he took the maneuver higher and further off to the left and ended slow on top, way off the final course and unprepared for the following descent. The reorientation to the intended flightpath while still inverted lead to an unplanned and unsafe increase in descent rate.

But sure it is pure speculation from my side. I have never flown the Hawk, all my flight time is in Phantoms.

A system fitted to prevent engine surging when guns where in use, I will leave the technical points out so as not to start a flurry of wild speculation.

I'm not too sure of your issue. You are happy to discuss various elements that relate to the Hunter but are unhappy to discuss elements that relate to that manoeuvre.

Sure let the AAIB make a report and let time pass while we wait but I am at a loss as to why you avoid what is a pretty fundamental point.

As no one is certain what the intended manoeuvre actually was, how can you expect someone to explain the potential errors ?

I don't have an issue, Pittsextra, but I am not about to compile a list of possible errors and their consequences that the uninformed or speculative out there might use as a checklist to draw inappropriate conclusions from.

If you are capable of describing the detail and dangers of a barrel roll in the 1999 Hawk Crash thread, I'm sure you could compile the list if you so wish.

ΔH, Avon-powered Hunters were prone to engine surge when the guns were fired, due to ingestion of muzzle gases. The only solution was to 'dip' the fuel supplied to the engine whilst the guns were firing, which briefly reduced the fuel supply during the half second or so during which the trigger was pressed.

Probably only a problem if all 4 guns on the SS Hunters were fired together, but fitted to all Avon-powered Hunters nonetheless.

Hunters whose guns were no longer used clearly didn't need the system and many had it disconnected under mod 1321. But following the loss of XL597, there was concern that the rotting old wiring might still be capable of interfering with the engine fuel supply, so the design authority required that all components and wiring associated with gundip were to be removed.

Courtney Mil will probably remember the rusty old knobs and tits on the F-4 centre pedestal left over from mud-moving days, which we air defenders never used. Apart from one chap, that is, who moved something and lost his tanks, or similar. From then on, the edict was "Don't touch anything!" on the centre pedestal, apart from the centre station selector for the gun.

Leaving old wiring in jets is never a good idea!

Well if someone else posts it saves the handbagging I got when I first posted!! That aside it might lead to a more obvious point than the GLOC, position of flaps, thrust and other less obvious chatter seen so far.. Above the clouds. I'm sorry of course it was a 1/4 clover let's not be silly

"Of course it was"? You sound awfully certain. Read post #431.

On a related note, LOTS of people were equally certain as you (and repeatedly stated) that the Thunderbirds F-16 ejection and crash at Mountain Home in 2004 was due to missing an altitude gate while performing a loop. And that is completely wrong.

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

Centreline tank - out of LU in Delta fit on a CAP. Bored nav was explaining how they made the switches to drop instant sunshine when he was on muds. Talked pilot through sequence, pilot pulled trigger - and tank dropped to high pitched scream from front seat. I was assured there was some semi-serious discussion of declaring an emergency and clearing all the stores before they fessed up....

I was the FA and told Ops XX was RTB Charlie fit - "no, he's Delta", said they. 'not any more", said I.....

IIRC they checked they rest of the fleet - they were in the only jet where the wires hadn't been cut IAW a mod......

Handbagging? Really? Your first post here was to make a pretty outrageous claim about the pilot's execution of an aerobatic manoeuvre, based on the claim of an old bloke that should know better.


If it helps, I'll explain what is wrong with that statement.

Badly executed figure. Please offer your aeros background on which you base that claim and it what way it was badly executed.

Was always going to lose height. Sorry, a statement based on what?

Which he does all the way to the buffet. How do you deduce he was in the buffet?

And subsequent stall. Again, show us how you know for a fact that he was in a stall.

You use those unproven assumptions to make a statement linked to Brown's assertion that it was the pilot's fault and you are then surprised that someone here picks you up on it? That wasn't a handbagging, it was you being, quite correctly, shown that your statement was unacceptable, unfounded and unwelcome.

As a reminder this is

Lots of others are welcomed here and we have many non-military regulars who contribute a lot to the forum. But people that come in here and spout stuff like that should expect to hear about it.

At the very least, don't whine about it when someone challenges your accusations against a former, highly professional, former military pilot.