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Originally Posted by Jayand
(Post 9098381)
It has been suggested in some corners that the pilot may have blacked out during the high energy manoeuvre. Whilst this is pure speculation it does raise the question should display pilots have an upper age limit? Is it right a 51 yr old was performing a high g manoeuvre? Do display pilots undergo strict annual medicals, ECG, blood tests etc? Flying military spec, even fifty year old jets is demanding and perhaps not for the more mature pilot? You don't see many fifty year old pilots in active FJ service very often, you dont see F1 drivers of that age.
I just celebrated my 49th birthday. Earlier on this year I tabbed the Fan Dance - 45lbs load, with a couple of additional diversions in a time which would certainly make me of no interest to the normal military community who do this - but was a league above the basic combat infantry standard (usually achieved by men in their late teens/early 20s). My point is: age is a number. Capability is something that you test with examination and achieve with appropriate training. I knew plenty of overweight, unfit military pilots in their 20s and 30s when I served and they all passed the same flying medicals as the "retired" ones who were still flying professionally. I think we can probably apply the same logic to the aircraft. I saw a wonderful display from the "vintage" vulcan this year at RIAT, but also recall seeing horrendous footage of a "serving" vulcan falling apart in mid-air. Very, very sad outcome - but the enquiry needs to establish the facts. Otherwise, according to this forum we should: a) Ban all flying, driving, walking around etc b) demand all citizens sign up to a declaration that its ok for them to be killed in the pursuance of other people's hobbies and interests c) we slap an age limit on everything - presumably eating at both ends of the spectrum as our prejudices dictate - until we conclude that no-ne should be trusted regardless of their age d) fly the arse off all the vintage aircraft until they do crash - because its art - at least for those lucky enough to see them before destruction - tough luck on future generations who might have more to learn/appreciate from an era further removed. CAA have sensibly put a limit of fly-pasts on "vintage" aircraft for the foreseeable future. At least we can still see these aircraft in the air - that's good enough for me because they cannot outfly or out-wow the modern stuff. One thing not examined in the forum is the culture of the organisation operating the aircraft? Why is it that BBMF can operate so prolifically, yet safely, compared to others? And they know a thing or 2 about showing-off the profile of a Spitfire's wings. |
One thing not examined in the forum is the culture of the organisation operating the aircraft? Why is it that BBMF can operate so prolifically, yet safely, compared to others? And they know a thing or 2 about showing-off the profile of a Spitfire's wings. |
I am not for a second saying the pilot was too old or unfit to display, but merely raising the question that these factors for display pilots should be considered.
It is a sad fact (I know too well) that things start to deteriorate as we get older, our eyesight, reaction times and strength etc all suffer as our years progress. At what point do we say you're too old for this activity or that activity? never if you're not putting anyone but yourself at risk I guess. Thankyou Courtney mil for the reply about US studies and G, interesting, am sure at some point though that age does become a factor. Above the clouds, re read my post, I stated that it was speculation but thanks anyway! and it was a military spec aircraft albeit as I said a fifty plus year old one and therefore combined with the manoeuvre a demanding aircraft to fly. |
Unless you go in for extreme aeros, I'm not convinced that being some racing snake or other serial jockstrapper has much relevance.
My first experience of 'g' was as a 15 year old cadet in the 'coal hole' of a Sea Vixen. I hadn't been briefed about 'g' and certainly greyed-out during the pull out from a simulated rocket attack. Then I went through training long before the introduction of the 'fitness test' and as a fully paid-up member of 'Athletics Anonymous*', never had no problems with 'g' tolerance. Even during a Hawk refresher after a tour on the tin triangle. We still took the Hawk to +7g at Chivenor - not often, but without the dubious benefits of centrifuge time it wasn't much of a problem unless you tried pulling whilst looking over your shoulder. That could hurt! Experience possibly develops an instinct of knowing when and how much to strain when under 'g'. Tailchasing in the Bulldog it wasn't unknown to see a much younger, fitter student having the odd 'quiet moment' during energetic manoeuvring. The last time I flew any aeros was at the age of 57 in a Chipmunk after a break of 2 years. It didn't have a 'g' meter, but we probably pulled about +4g in a loop - again, no problem even for a non-athelete. Routine Class 1 medicals were fine, but I got fed up with the cost! So no, a pilot with a Class 1 and plenty of 'g' experience in his/her background shouldn't have any great problem flying relatively benign aeros in the Hunter T7. *Athletics Anonymous - if you have a sudden urge to commit sport, you phone up a mate who talks you into going to the pub instead:ok: |
BEagle, yes I agree totally with what you say there.
Jay and, I'm sure you are right about a sell-by date, but I expect that there will be other physiological factors that would make one unfit for the high-g, high-performance cockpit before G-tolerance in most cases. As pilots doing aeros probably don't go in a centrifuge every year (most probably ever) they're unlikely to be aware of when their g-tolerance starts to change. As BEgle says, this type of aeros isn't going to expose anyone to that much g anyway. Also remember that that there are lots of other factors that are more likely to affect this: dehydration, fatigue, medication, minor illness among others. Most professionals, especially those with a fast jet background will have a pretty good understanding of these things. Again, too early to try to apply any of these things to this accident. Rule nothing in, rule nothing out. |
I am in a part of world where the servers don't allow access to many online papers and the news channels have stopped discussing the accident, question.
How are the recoveries of Andy and those injured progressing ? |
I don't think you're missing anything on that topic, ATC.
BTW, if you need help plugging in to the servers from overseas, try Zen Mate - there's a small subscription now for you want to do. Other, similar apps are available. |
I think we can probably apply the same logic to the aircraft. I saw a wonderful display from the "vintage" vulcan this year at RIAT, but also recall seeing horrendous footage of a "serving" vulcan falling apart in mid-air. http://forum.keypublishing.co.uk/att...hmentid=146873 Sadly, I believe it killed 3x AVRO test pilots and 1x RAF navigator in the aircraft and then on the ground 3x RAF personnel in the runway caravan. |
Thank you CM for the update.
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VX770 did not "fall apart". If you bother to read the report you will find that the aircraft suffered structural failure after severe overstress and gross exceedence of its limited release.
OAP |
Leon and Onceapilot, '770 had very probably been overstressed beforehand by Rolls Royce (and perhaps RAF pilots) during repeated aerobatics, such as were frequently seen over Hucknall after RR engine trials. One pilot is thought to have looped the aircraft, although barrel rolls and rolls-off-the-top were more normal.
As the first prototype, '770 wasn't as strong as production Vulcans and RR didn't conduct the internal leading edge checks which Avros did after any aerobatic flights. Neither is it by any means certain that the Syerston accident was caused by the pilot either flying too fast or rolling and pulling - he could have been flying within the planned flight parameters but in an aeroplane which had been severely damaged by others. It was all too easy to find 'pilot error' as the 'obvious' cause in those days.....:uhoh: On the subject of 'g' tolerance, I know of a chap who's over 60, yet regularly flies to high 'g' limits in fast jet aircraft.... Perhaps old age and treachery does indeed always overcome youth and skill? |
Originally Posted by Above The Clouds
I am in a part of world where the servers don't allow access to many online papers and the news channels have stopped discussing the accident, question.
How are the recoveries of Andy and those injured progressing ? Pilot transferred to unnamed specialist hospital 3 or 4 days ago, that's about all. Still only about half the deceased victims formally named (edit 8th just named). DNA tests required for some ... Road still closed, and once open may be one lane only westbound for a while. |
A great many on here evidently have no clue - not unreasonably given the specialist nature of the discipline - and therefore I think it IS helpful to rule out some of the wilder theories that serve to call into question the safety of other, similar or even unrelated, aviation activities without good reason.
I am not suggesting that we lay out all of the details that an experienced eye can elicit from the evidence available so far - for a start, we understand the difference between causal factors and blame - whereas I have no confidence that the press does. For that reason alone, I suspect that those of us who can make logical conclusions will not post them in open forum - which, unfortunately, leaves a gap in the market for those who do not have the experience to deduce but are prepared to speculate - such as the priceless Mr Sharp. However, please cease with the 'it is not possible to draw any conclusions'... Many of us have grown up with the understanding that any speculation is unhelpful in a time when accidents happened without video - and often even without witnesses, and when the priority was to inform NoK, formally, as quickly as possible - often in circumstances of some confusion. The circumstances of Shoreham are entirely different - and the public have a very legitimate interest in what went wrong - one that, arguably, exceeds our traditional sensitivity to anything that might be regarded as critical of individuals. In this instance, I don't think it is unhelpful or unreasonable to observe that the aircraft was pitching throughout the recovery - therefore AH was providing a control input and g-loc CAN very reasonably be ruled out. Deduction, not speculation. CM - I know you will respect the sensitivity so I'll PM you with more later, to both demonstrate my restraint as well as illustrate what CAN be ruled in/out, and what cannot... |
BEagle. 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. The 207 didn't suffer from as many airflow problems and didn't require either system. BTW. The take off looked and sounded exactly right too. That climb out could have been at Penycwm. The engine sounded healthy right to the end. Sorry to Nit Pick. :ok: |
Thanks for the gen., Mrmungus! I knew that the F6 and FGA9 didn't have the HPPIS, but I didn't know that gundip wasn't required for 200-ser Avon-engine Hunters.
Never too old to learn something new! |
In this instance, I don't think it is unhelpful or unreasonable to observe that the aircraft was pitching throughout the recovery - therefore AH was providing a control input and g-loc CAN very reasonably be ruled out. Deduction, not speculation. |
I didn't actually think he pulled a lot of g. Looked quite lazy and smooth. Too old to fly I think is when you fail the medical.
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I concur, to me I think it was a factor of a modified 1/4 clover and then an oblique pull through that meant that the normal gate height would probably have been too low. Normally a 1/4 clover would be from 90 degs from the crowdline but the position of Lancing and Lancing College make this difficult. That's always been my opinion of civilian authorised displays compared to military authorised displays - the military ones are 'set piece' and not for modification, whereas, the civilian displays can be modified as required by the pilot. I remember watching a very experienced ex-mil pilot put an extra roll in his display over-sea and he did not recover. The UK military PDA regime is far more restrictive and modification to the authorised 'full', 'rolling' and 'flat' displays is not allowed as far as I'm aware.
That's my theory, anyway. Don't think it will be G-loc or overstress looking at the numerous videos. If he lost his engine at the top of the vertical manoeuvre then he would have rolled out and then gone for a FL towards the field, if he lost the engine going downwards then he would have been at idle anyway. But, hey, here's hoping the AAIB release something soon to stop speculation and actually report facts - rather than our best guesses. Of course something could have gone wrong with the jet, but I don't see any significant evidence to support that. I do think the CAA have been right to enforce the restrictions they have - I don"t see them as 'knee jerk' as some have opined. Sorry if my speculation upsets anyone. I do know one of those killed and one who is seriously injured so I think I am within my moral rights to comment 1 week later. LJ |
Age in itself is not a factor in a pilot's ability to do aerobatic manoeuvers in a fast jet - being medically and physically fit enough and practiced in coping with the rigors of the manoeuvers is.
All the pilots in the US "Starfighters" Team - flying a much higher performance aircraft than the Hunter - must be in their 60s/70s from their bios: KVDV, Inc. - Starfighters Crew https://www.youtube.com/watch?v=jJ6K_U1zPi0 https://www.youtube.com/watch?v=gOwIdAXlgPg |
For what it's worth Leon, you've got my vote . . .
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Brian
Yes, Occam's Razor is normally the way that these things play out. CPL Clott |
Originally Posted by Onceapilot
(Post 9098804)
VX770 did not "fall apart". If you bother to read the report you will find that the aircraft suffered structural failure after severe overstress and gross exceedence of its limited release.
OAP Not that one, and apologies for not having a reference - but I remember being shown a video during a lecture of some sort, where a number of panels and possibly parts of the air brake detached. My memory is not clear but I'm sure it was a serving Vulcan - as not long afterwards I attended an airshow and watched a Vulcan display. I'll try and dig out further info. |
Daily Telegraph reports that the AAIB discovered a flaw in the Hunter, in 1998 called an HPPIS. If operated with the throttle open would cause 'an almost instantaneous destruction of the engine'.
What is an HPPIS? I have never heard of it. It seems that this has been resonsible for 20 Hunter crashes. Looks to me like two journalists have got their knickers in a twist and mis-quoted the true facts! |
High Pressure Pump Isolate Switch, I think.
I'm guessing the Telegraph journalists are talking about the loss of G-HHUN: https://assets.digital.cabinet-offic...pdf_502233.pdf |
HIGH PRESSURE PUMP ISOLATION SWITCH (HPPIS). When the switch is set to ISOLATE, one HP pump is cut off from the servo system which continues to control only the other HP pump.
Extracts from an old AAIB report: In May 1980 an RAF two seat Hunter T7 experienced a power reduction, and a hot relight was attempted. As this was being completed by one pilot, the other pilot had retarded the throttle slightly and operated the HPPIS as the first pilot ceased pressing the relight button. The engine speed increased to 6,000 RPM, but the EGT exceeded full scale deflection and the engine began to vibrate. The instructor took control and advanced the throttle slightly, whereupon there was a slight increase in engine speed, followed by a 'muffled bang' and the engine speed then decreased rapidly. Both pilots then ejected safely, but the aircraft was destroyed in the ground impact and post crash fire. The power reduction was attributed to an unidentified failure in the fuel system. In December 1981, another RAF Hunter T7 experienced an engine malfunction while preparing to land. At about 1000 feet agl and after selecting flap, gear down and airbrake in, and as the airspeed decreased through 250 kt, the instructor advanced the throttle slightly. Both pilots then noticed a slight 'rumbling sound' and that the indicated engine speed was lower than expected for the throttle setting. The instructor moved the throttle further forward, but the engine did not respond. He then operated the HPPIS and the engine speed increased as expected before reducing to low RPM. At about that time, witnesses on the ground saw a plume of flame from the aircraft's jetpipe. Both pilots then ejected safely. Subsequent examination of the wreckage found that the engine turbines had experienced severe in-flight overheat damage. A fault was later found in the BVCU diaphragm which had caused the compressor to stall as the throttle was opened. It was subsequently established that the HPPIS had been operated while the throttle had been set to a position corresponding to about 7,000 RPM. In addition to these accidents, records kept on a computerised database between 1980 and 1992 showed 22 cases involving the Avon Mk 122 engine where engine speed had dropped and subsequent engineering investigation had not established a clear cause. Anecdotal evidence indicated that Avon Mk 122 engines had suffered from unexplained power reductions from time to time during RAF service, but in most cases the aircraft had returned safely and the subsequent RAF engineering investigations, including related engine ground runs, had failed to identify associated causes or to reproduce the symptoms. |
Just a thought and not aimed purely at AH but if you constantly fly a number of airframes can this cause a possible problem of handling issues etc. This is too aircrew as I have always been interested to find out regardless of this particular incident.
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Bigbux
You may be thinking of the accident at RAF Wyton on 29 Jun 1966, when Victor SR2 XM716 was destroyed. IIRC the B of I found that the cause of the accident was pulling rolling G at speed outside the aircraft Release to Service limits. |
Elevator PFC manual reversion?
PFC manual reversion has also been accountable for Hunter losses in service although aileron reversion is more tricky AIUI. |
I've been following the thread but not closely enough so apologies if this has been mentioned. Didn't a US Aggressor company lose a couple of Hunters in quite quick succession recently - were the circumstances similar? I wonder if it won't be regulation that stoofs event flying; rather, the cost of indemnity.
Does anyone know how much it costs to insure a private flying operation, and what the scrutineering and underwriting criteria will now include? That's not a rhetorical question, I don't know and would be interested to get an idea. I've managed to get some suitably qualified and experienced clients who do event flying at standard rates, it'll be interesting to see how more resilient underwriters become to shouty people who can argue a case with (generally) more insight. |
My copy of Hunter T7 pilot's notes, last amended 1972 states the following in the Emergency Procedures section.
"Sudden drop in engine speed....below 20,000 ft. If the engine fails to respond to normal throttle movements close the throttle fully and set the HP isolating switch to ISOLATE." |
Originally Posted by Al R
I've been following the thread but not closely enough so apologies if this has been mentioned. Didn't a US Aggressor company lose a couple of Hunters in quite quick succession recently - were the circumstances similar?
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On the question of whether indemnity/ insurance costs might have a greater impact than any regulation changes, I think that there is reason to think that this is unlikely.
Insurance underwriters are fairly dispassionate and analytical as a breed, and of necessity look through the human aspects of accidents to the financial. Courtesy of the 1700 or so deaths on UK roads each year, not to mention a much larger number of injuries, there is a substantial body of case law, not to mention custom and practice which enables underwriters to assess the likely financial impact of loss of life and serious injury resulting from an accident involving one of their insured. In arriving at their premium rates, insurers use sophisticated risk assessment and management techniques, and I believe that dramatic premium increases for all insured tend only to arise where something transpires which changes the risk landscape fundamentally. In this case despite the horror of what has happened, I do not believe that the outcome has a significant impact in underwriting terms: the possibility of an insured aircraft having an accident and giving rise to third party claims will have been one of the risks understood when premium rates were established. Whilst the loss of so much human life has shocked us all, the eventual cost of the accident to the underwriters may well not fall outwith their estimates for a such an eventuality, bearing in mind they will have had to consider hypothetical scenarios such as a FJ crashing into, say, a shopping mall, etc etc. In considering future underwriting rates, they will focus on whether the risks have gone up, down, or stayed the same. Even if there are no regulation changes (unlikely I think) all operators and pilots will, at least for a time, become more conservative, with the result that the prospects for a similar event reduce, and hence the risk insured goes down. All rather dispassionate, and not intended to suggest that on a human level, underwriters would be any less shocked than the rest of us. |
Yes, ATAC lost two Mk.58's, one in 2012 and another in late 2014. Pilots killed in both incidents. Pilot of the 2012 crash had reported fuel transfer problems just prior to the crash, and I've not seen any reports yet about the 2014 crash on approach to Point Mugu. Both pilots lost control on approach and crashed! I do not believe that this had any relevance to the Shoreham crash. While I am writing I will express my disgust at the Daily Telegraph for an article published on Saturday. They showed a picture of a Mig followed by an article about the Shoreham accident. The authors had clearly done a Google search and then just quoted a part of an Accident Report from an accident at Dunsfold. There would appear to be no connection or relevance to what was written. It appeared that the authors knew nothing about aviation, let alone display flying or jet aircraft. IMHO the Editor should not have published the article and deserves grief from all interested. I have written to the Editor expressing my concerns. I was also surprised to learn that many vintage jet aircraft fly without cartridges in either their ejection seats, or external drop tanks when carried. Apparently this is due to the cost of storage and servicing of explosive cartridges! Is this correct? |
falcon900. Sorry but I do not think your rosy view of insurance premium calculation ties in with the reality of the insurance market that I have experienced. Your simplistic description would see all insurance at fixed risk-cost, independent from claim history and specific risk. Please put me in touch with an insurer who operates in the way you describe.:ok:
OAP |
OAP,
If you read what I wrote again, you will note that I specifically referred to insurance rates "for all insured", i.e. the market. Individual insured do indeed see an impact on their premiums after a claim, but single events do not tend to drive up the market rate unless there is something truly exceptional in relation to ongoing risk. |
Loss history definitely plays a role in the cost of insurance, but the overall trend is unambiguously downward thanks to improving aviation safety. There are plenty of people willing to bet that this trend will continue over the long term, despite the odd outlier.
At the same time, ultra-low interest rates mean there's a lot of money in financial markets looking for a better return. Plenty of this has found its way into insurance and reinsurance markets, and that's also keeping premium costs down. |
This had NOTHING to do with HPPIS operation or BVCU failure.
The Dec 81 crash was on (Our) engine air test and we were waiting for it to land. The flame from the rear was a good 40ft long. We thought they had gone in with it. Even the guy in the tower (I met him in the Falklands) who hit the crash button didn't see a parachute. Both seats both pilots the canopy AND the A/c were all in the same small field. It was very very close. At Shoreham there was no flame, no unburned fuel (white smoke). It sounded normal in all video i have heard Listen to the dash cam video). No pops or bangs. there was a nice shot from above showing hot efflux. I am certain that engine was running normally. The drop tanks. Yes it is acceptable to have no carts in the ERUs (In Civi use). I don't know if these were armed or not but I doubt it. Indeed the Swiss disabled all their inboard tank jettison to make sure they would not drop off. It's been 30 years but I'm sure the T7 had no rear tank, so even had it been a full fuel load or similar at take off the droppers would have fed first and been empty or had little left. Seats are a different matter. That I believe is the operators choice. MB have said they are no longer going to support old seats. Who can blame them when you think of the vitriol thrown their way after the Scampton failed ejection. Australia have stopped flying their historic flight Sabre because of this issue. Hope this helps MM |
Elevator PFC manual reversion? |
Not sure that is accurate Pontius. The speed involved off the top of the loop would be low enough to allow reasonable stick pressure. As I recall, it only became a real problem above about 360 knots. Would the hydraulic failure warning horn have given time to abandon the manoeuvre before the controls reverted to manual? Mind you it is some years since I was instructing on the Hunter! Maybe a Hunter QFI would like to remind us?
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Elevator PFC manual reversion? The fact that AH lost control on his very first manoeuvre of the display makes it easy to believe that partial incapacitation was a cause. |
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