PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Military Aviation (https://www.pprune.org/military-aviation-57/)
-   -   Shoreham Airshow Crash Trial (https://www.pprune.org/military-aviation/619209-shoreham-airshow-crash-trial.html)

just another jocky 8th Jul 2020 15:05


Originally Posted by airsound (Post 10831879)
But as you will have seen from the Conclusions of the AAIB report Also, from the Prosecution's 53-page opening handout which I referred to in post #589 So neither the AAIB, nor the Prosecution, support your view. Indeed, the Prosecution charge relied on AH's being suitably experienced and qualified to fly the display – inexperience cannot equate to negligence.

airsound

I went through a similar system to get my DA on the Hunter T7. Albeit with a lot of years flying fast jets (though none of it flying low level aerobatics), it took me 3 trips to go solo in the Hunter (an aircraft I had never flown before) and a further 4 to get my low level DA. At the time I was naďve enough to just go along with it as I believed I was safe and circumspect about what I attempted and the manoeuvres we planned for our displays were all very 'safe' with no nose low commits as we weren't experienced enough.

Was that enough to then fly within striking distance of 000's of people, plus those outside the fence who were just going about their daily business? In hindsight, I think not. When you compare what I did to what an RAF pilot will have to go through to get a DA, on a type they're already current on and the gulf is huge, perhaps more than huge. And of course once they have a DA, it's only for the manoeuvres they are cleared to do whereas I was then cleared to fly any manoeuvre I chose at the time.

AH was current and fit in terms of the regs at the time, that doesn't mean it was safe, at least in my opinion. The system failed those victims and their families

GeeRam 8th Jul 2020 15:13


Originally Posted by Bob Viking (Post 10832076)
Firstly the lack of research into CI may well be something that should be rectified. From the defence point of view that was probably a good thing of course. A little understood phenomenon is a perfect way to sew seeds of doubt into the minds of a jury. I realise that sounds like I am accusing them of Machiavellianism but I am just pointing out how a legal defence works in reality.

Yep.
I served on a jury over 30 years ago, where the defence team did a similar thing and utterly confused and brain-numbed most of the jury, who had been given enough 'seeds of doubt'....to bring a not guilty verdict despite the hard evidence presented.
As pointed out in other posts, its all a 'game' played by legal teams.

As pointed out the system failed as much as AH did.
As per AAIB report, that was only his 5th Hunter display that season, and given Shoreham was Sept and thus pretty much near the end of the display season, yet the system thought that was adequate for a FJ display DA when you have less that 40 hrs on type, is.......well......



LOMCEVAK 8th Jul 2020 15:31


Originally Posted by Bob Viking (Post 10832076)
Surely to pull through from a loop that has apexed at 2800’ actually requires incredible skill and concentration. Any lack of consciousness or awareness would surely have resulted in a vertical ground impact rather than a (miraculously) survivable almost level attitude?

I can only put this accident into Hawk terms but I know that if I were to apex 1500’ lower than intended and continued the manoeuvre I would be incredibly lucky to complete the second half before ground impact. I can’t imagine a Hunter is markedly different in that regard.

BV, there is data supporting your assumption in the AAIB report. The aeroplane had to be flown at maximum instantaneous turn performance (light buffet) throughout the pull through to achieve that radius. Assuming that the aircraft was trimmed in pitch at the pull-up point, this would have required a significant (but easily applied) aft stick force and displacement throughout the manoeuvre. There are a couple of extra significant considerations.
First, analysis of the external videos showed that at some point in the manoeuvre the flaps were selected from 1 notch to 2.
Secondly, during the last quarter of the manoeuvre when about 30 degrees nose down the aircraft entered wing rock which would have been caused by a further aft stick input increasing angle of attack past the maximum value ie. the aircraft was pulled into an accelerated stall. This would actually have increased the height loss slightly but was, in my opinion, a totally instinctive control input and did indicate to me that the pilot was aware of the aircraft's flightpath with respect to the ground.

Your comparison with the Hawk is interesting because the Hunter is actually a lot easier to fly in situations such as this. It has a progressive increase in buffet intensity as AoA is increased compared to the Hawk as so is much easier for maintaining maximum instantaneous turn at all airspeeds.

beardy 8th Jul 2020 16:59


I know you and I are never likely to agree on this (yes I know you sat in court and I fully understand my thoughts really don’t matter in the grand scheme of things) but I think we can both accept that in any court case an innocent verdict does not mean that the complete truth has been presented and accepted.
The verdict was not guilty of the charges brought against him, not that of innocence.

Caramba 8th Jul 2020 18:19

Beardy - the trial was in England; AH was found not guilty of the charges against him. There is no “not proven” verdict south of the border, and, technically, no court declares someone innocent.

Because of the “not guilty” verdicts, AH was acquitted and thereby absolved of the charges. Sounds like innocent to me.

Caramba

Odanrot 8th Jul 2020 19:14


Originally Posted by LOMCEVAK (Post 10832105)
BV, there is data supporting your assumption in the AAIB report. The aeroplane had to be flown at maximum instantaneous turn performance (light buffet) throughout the pull through to achieve that radius. Assuming that the aircraft was trimmed in pitch at the pull-up point, this would have required a significant (but easily applied) aft stick force and displacement throughout the manoeuvre. There are a couple of extra significant considerations.
First, analysis of the external videos showed that at some point in the manoeuvre the flaps were selected from 1 notch to 2.
Secondly, during the last quarter of the manoeuvre when about 30 degrees nose down the aircraft entered wing rock which would have been caused by a further aft stick input increasing angle of attack past the maximum value ie. the aircraft was pulled into an accelerated stall. This would actually have increased the height loss slightly but was, in my opinion, a totally instinctive control input and did indicate to me that the pilot was aware of the aircraft's flightpath with respect to the ground.

Your comparison with the Hawk is interesting because the Hunter is actually a lot easier to fly in situations such as this. It has a progressive increase in buffet intensity as AoA is increased compared to the Hawk as so is much easier for maintaining maximum instantaneous turn at all airspeeds.

There is also the fact that the Hawk behaves as a straight wing aeroplane whereas the Hunter a swept wing aeroplane, and therein lies the difference.
In a Hawk max CL comes as you achieve light buffet, pulling through this does not increase CL but actually reduces it, a straight wing characteristic. In the Hunter light buffet gives optimum CL for hard manoeuvring, but not max CL, that is achieved by continuing to pull into heavier buffet, ie wing rock, but with an unacceptable increase in drag, So, While you can get more out of the wing if you hold deeper buffet for any length of time, the loss of speed, ie energy, negates the CL advantage gained earlier.
To me this explains the wing rock In the last quarter of the loop and the fact that he didn’t tent peg. Whether or not AH was aware of this is irrelevant as most people put in this position would pull harder. Had he been in a Hawk and missed his gate height by a similar margin and not flown an escape manoeuvre he would have arrived at ground level in a steep dive, but the Hunter achieved a nose up attitude at impact albeit still descending.
He knew he was in the s.... and tried to do something about it !!! But decided not to eject.

RetiredBA/BY 8th Jul 2020 19:29

Whatever he decided an ejection in the last quarter of the loop was almost certain death.

MB. say, in those seats, you need a height of at LEAST 10 % of your ROD to survive.

He did not have that height.

He had no option but to pull to, or through, the buffet to obtain Max Cl.

The video shows max or near max, elevator deflection which suggest he was pulling hard, a natural instinct if you are about to hit the ground !

beamer 8th Jul 2020 19:36

I still find it surprising that so many people cannot accept the idea that, on the day, a pilot made an unintentional mistake with tragic consequences.

Odanrot 8th Jul 2020 19:47


Originally Posted by beamer (Post 10832303)
I still find it surprising that so many people cannot accept the idea that, on the day, a pilot made an unintentional mistake with tragic consequences.

Where do you get the idea that anyone here feels that his “mistake” was anything other than unintentional? The discussion is about possibilities of how it happened and being discussed by professional pilots (some retired) who have thousands of hours flying Hunters and other fast jets.

beardy 8th Jul 2020 21:41


Originally Posted by Caramba (Post 10832237)
Beardy - the trial was in England; AH was found not guilty of the charges against him. There is no “not proven” verdict south of the border, and, technically, no court declares someone innocent.

Because of the “not guilty” verdicts, AH was acquitted and thereby absolved of the charges. Sounds like innocent to me.

Caramba

In that case we shall have to disagree on the term 'innocent'

Hot 'n' High 9th Jul 2020 08:32


Originally Posted by LOMCEVAK (Post 10832065)
.......

I believe that with a manslaughter charge such as the one that is being discussed here the verdict has to be based upon 'beyond reasonable doubt' rather than a 'balance of probability' (legalapproach please correct me if I am wrong).

I should have put "Just because a Court decides that, on the balance of probability, something happened in a certain way actually has no bearing at all on whether it actually happened or not in that way." :ok: H 'n' H trying to sound "intelligent" backfires on him yet again!!! You'd think I'd learn.......! :}

However, my error does not detract from the heart of my Post, which was put far better than I did by Thud105 a few posts up and that is that the legal-beagles "still do their very best to help their client avoid ‘Justice’ by careful manipulation of ‘The Law’" (which is even their Duty so I believe - as a laybod I hasten to add) and by GeeRam that, from their own experience, has observed a case where "........ the defence team ........ utterly confused and brain-numbed most of the jury, who had been given enough 'seeds of doubt'....to bring a not guilty verdict despite the hard evidence presented.".

Quite what was/was not applicable to the Case under discussion in this Thread I know not, nor care, as it changes nothing in the Case in question, nor will it change the way legal things are run in the future (particularly given my experience with my Judge-"friend" and others I've met who are in the legal world) - just that my faith in Justice generally being done within the UK legal system is, well, virtually zero! As POBJOY says, "and this is why the trial did not get to the root cause" - the "players" only looked at what suited them in terms of the basis for the prosecution and the subsequent defence. As just another jockey said, "The system failed those victims and their families". Actually, that's "systems" - the Aviation one and the Legal one!

I'm not sure what the mathematical term is for a graph with two peaks, one at either end and a smattering in the middle (a Camel Curve maybe? I'm sure several PPRuNers will know). If you took a straw poll here, today, based on all that is known, observed, guessed or derived by some other means, with "Totally professionally executed display written off by a CI event" through to "A series of intentionally flown deviations (which did not, I hasten to add, have the intent to crash the jet - just to produce an ace display)" I'd expect something like a Camel Curve to emerge.

Ah well, I've had my say - I'll slink back and await that effigy of H 'n' H to be constructed by Legalapproach - clearly, La was busy doing other things yesterday so no stabbing pains ..... yet!!!! :ooh:

Legalapproach 9th Jul 2020 19:26

H'n'H

She who must be obeyed has me decorating the hall so up a ladder yesterday. In any event it will be, like the key cross-examination question, when and where you least expect it. I'm just biding my time.

And to clarify, by hall I mean the bit behind the front door where we hang the coats and dog leads, not Hall as in Legal Towers before any of you b****** start going on about vast fees. Vast fees? - we were on legal aid.

Hot 'n' High 9th Jul 2020 20:25


Originally Posted by Legalapproach (Post 10833248)
H'n'H
............

And to clarify, by hall I mean the bit behind the front door where we hang the coats and dog leads, not Hall as in Legal Towers before any of you b****** start going on about vast fees. Vast fees? - we were on legal aid.

No probs Leags, and sorry I'm such a cynic in such matters. I'll expect the stabbing pains once you've had a chance to construct an effigy of moi now you have been released from hard labour. My front door has taken 2 weeks now due to inclement Wx! I share your pain!

I think we can all agree that Shoreham was a disaster on a personal level for so many people, a disaster for the air show scene - tho with benefits in highlighting a load of areas which need reviewing - and an utter disaster for AH himself as he has to live with this for the rest of his days. Summary? A right mess!

Let's just hope genuine progress is made, taking everything into account as hard as that may be. At least that will be a fitting epitaph for those who have sadly paid the ultimate price. Cheers, H 'n' H

Dan Winterland 10th Jul 2020 07:55


John Derry aircraft exceeding its design limits
The DH110 design had one major flaw in the straight tailplane which would suffer from compressability before the mainplane - a bit of a disaster for stability at high Mach numbers. In service, the MNO of the Sea Vixen was subsonic. Dan Griffiths, while displaying the last airworthy Sea Vixen had some thoughts on the matter.

https://vintageaviationecho.com/flying-the-sea-vixen/

wonderboysteve 13th Jul 2020 12:33


Originally Posted by Dan Winterland (Post 10833578)
The DH110 design had one major flaw in the straight tailplane which would suffer from compressability before the mainplane - a bit of a disaster for stability at high Mach numbers.

Was that definitely the case? I hasten to add that I don't know in the case of the Sea Vixen, but a straight tailplane would not inherently suffer from compressability issues before the mainplane, if it had a thickness to chord ratio that was sufficiently lower. The greater lift curve slope of the straight tailplane versus the swept wing would help to maintain manouvre margin with increasing Mach number. I read through the article but couldn't see a reference specifically to the tailplane suffering as opposed to the mainplane.

Dan Winterland 14th Jul 2020 07:04


Was that definitely the case? I hasten to add that I don't know in the case of the Sea Vixen, but a straight tail-plane would not inherently suffer from compressability issues before the main-plane, if it had a thickness to chord ratio that was sufficiently lower. The greater lift curve slope of the straight tailplane versus the swept wing would help to maintain manouvre margin with increasing Mach number. I read through the article but couldn't see a reference specifically to the tailp-lane suffering as opposed to the main-plane.
I recall reading about it elsewhere some time ago, but I don't recall where. A straight plan-form can be sufficient for high speed flight if the fineness ratio is high - as in the F104. longitudinal stability at high speed is a favourite interview question - "why do airliners have greater sweep on the tail-plane compared to the wing?" (The 747 has the same sweep on both, but gets round it with a greater fineness ratio). But looking at a picture of the Sea-vixen, there does seem to be a bit of camber on the tail-plane. The tail design went through several changes and although the DH110 achieved supersonic flight in testing, in service it was limited to a very low M0.92 considering it's role.

Dan talks about pitch stability at the extremities of the range in his article and attributes much of this to elevator gear changing. But an ex-colleague who flew them mentioned the dreadful high speed handling of the Sea Vixen. It was so powerful, you could get to VMne very quickly and it was easy to exceed. My friend scared himself several times and remarked that he was glad when the Phantom came along as he considered it far safer and that he was 'on borrowed time'. If you consider the F4 to be safe, then that says something about the aircraft you were flying before! And the statistic of some 40% of the fleet lost in accidents also says something.

wonderboysteve 15th Jul 2020 07:50

DW - thanks for your response! I'll PM as this is far from topic.

TC_LTN 3rd Dec 2020 14:30

CAA Report
 
A very interesting read;

https://publicapps.caa.co.uk/modalap...detail&id=9876

Training Risky 3rd Dec 2020 14:50


Originally Posted by TC_LTN (Post 10939666)

Yes indeed!

From this excerpt below, it appears that AH's defence of cognitive impairment has been disproven:

"9.60 There is no evidence to suggest that cognitive effects can be demonstrated at low levels of G force when experienced for the short period of time associated with aerobatic displays. The overwhelming weight of available scientific evidence does not show any demonstrable, practical and meaningful cognitive impairments under +4 Gz that would point to impaired flight safety."

"9.61 The Review Team has concluded that there is no identifiable risk of cognitive impairment in civil pilots experiencing G forces at levels, and for durations recorded by accident investigators as having been experienced by the Shoreham pilot."

"9.62 This review makes a number of recommendations for the CAA to consider. The recommendations are weighted towards improving the safety of flights where aerobatic manoeuvres are undertaken as these are the flights where levels of G above +2 Gz are likely to be experienced and physiological effects could be encountered. The focus has been on safety improvement."

"9.63 None of the recommendations are considered to be urgent safety recommendations."
(Really!! I am sure the Shoreham families may disagree?)

So according to this report, he just entered the loop too low and slow and didn't realise it until too late.

just another jocky 3rd Dec 2020 16:10


Originally Posted by TC_LTN (Post 10939666)

"The overwhelming weight of available scientific evidence does not show any demonstrable, practical and meaningful cognitive impairments under +4 Gz that would point to impaired flight safety."


All times are GMT. The time now is 21:45.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.