Shoreham Airshow Crash Trial
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.
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.
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.
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.
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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
Because of the “not guilty” verdicts, AH was acquitted and thereby absolved of the charges. Sounds like innocent to me.
Caramba
Last edited by Caramba; 8th Jul 2020 at 18:26. Reason: Spelling
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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.
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.
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.
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 !
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 !
Last edited by RetiredBA/BY; 8th Jul 2020 at 19:46.
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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 - 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
Because of the “not guilty” verdicts, AH was acquitted and thereby absolved of the charges. Sounds like innocent to me.
Caramba
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!!!!
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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.
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.
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
John Derry aircraft exceeding its design limits
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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.
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.
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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.
Versus:
"In the absence of direct evidence there remains the possibility that some aspects of pilot performance could be affected at levels of +Gz lower than those associated with effects on vision and consciousness, though these may only relate to longer durations of exposure. It is not possible to state from the data available whether any of the impairments would have occurred at much shorter durations than those reported in the literature".
"Few studies have been undertaken on higher mental functions with low G force. In part this is due to the difficulty of accurately measuring these functions in a +Gz environment. Varied study designs, methodologies, differences in choice and experience of participants, individual differences between participants and levels of Gz have been employed in studies and this lack of consistency makes comparisons challenging"
"In the absence of direct evidence there remains the possibility that some aspects of pilot performance could be affected at levels of +Gz lower than those associated with effects on vision and consciousness, though these may only relate to longer durations of exposure. It is not possible to state from the data available whether any of the impairments would have occurred at much shorter durations than those reported in the literature".
"Few studies have been undertaken on higher mental functions with low G force. In part this is due to the difficulty of accurately measuring these functions in a +Gz environment. Varied study designs, methodologies, differences in choice and experience of participants, individual differences between participants and levels of Gz have been employed in studies and this lack of consistency makes comparisons challenging"
"There is no evidence to support the existence of cognitive effects prior to a level of G where grey out or blackout affects vision."
"A considerable number of international aviation organisations were contacted, for the purpose of this review, to ask for any information or concerns they may have been aware of relating to cognitive impairment with G force. No respondents described cases that fitted the criteria of acceleration-induced cognitive impairment at relatively low G force. The RAF Centre of Aviation Medicine informed the review that following consultation with international colleagues and experts ‘no consulted expert or organization recognises the existence of a low-G impairment syndrome’ and that ‘the total unanimity and unambiguous nature of expert opinion and long-term international experience offers significant reassurance’"
Does that make the report confusing and/or contradictory then?
"A considerable number of international aviation organisations were contacted, for the purpose of this review, to ask for any information or concerns they may have been aware of relating to cognitive impairment with G force. No respondents described cases that fitted the criteria of acceleration-induced cognitive impairment at relatively low G force. The RAF Centre of Aviation Medicine informed the review that following consultation with international colleagues and experts ‘no consulted expert or organization recognises the existence of a low-G impairment syndrome’ and that ‘the total unanimity and unambiguous nature of expert opinion and long-term international experience offers significant reassurance’"
Does that make the report confusing and/or contradictory then?