RAF rotary crash Snowdonia
Avoid imitations
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An interesting report.
The points made about the Griffin having been habitually flown beyond its limits w.r.t. "aerobatics prohibited" are highly relevant to other recent discussions, following the publication of a video of the wingover manoeuvre flown in an AS355 just prior to landing.
Those saying no harm can be done to a helicopter by "aerobatics" (and what constitutes an aerobatic manoeuvre) might like to read up on this one and think again.
Thankfully, no-one was hurt but the story could have been very, very different.
The points made about the Griffin having been habitually flown beyond its limits w.r.t. "aerobatics prohibited" are highly relevant to other recent discussions, following the publication of a video of the wingover manoeuvre flown in an AS355 just prior to landing.
Those saying no harm can be done to a helicopter by "aerobatics" (and what constitutes an aerobatic manoeuvre) might like to read up on this one and think again.
Thankfully, no-one was hurt but the story could have been very, very different.
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Crikey, page 173
Bell design manouver limits 50 AOB and 15/30 down/up pitch were the maximum values considered for Certification
MOD applied limits 90 AOB and 90 pitch.
I seem to remember in my past life the Lynx being demo'ed rolling, the first for its time, however I was also informed at the time the main rotor gearbox on it had to be replaced within 10 hours due to the stresses on it, whether correct i do not know, but at the time I was told that.
Bell design manouver limits 50 AOB and 15/30 down/up pitch were the maximum values considered for Certification
MOD applied limits 90 AOB and 90 pitch.
Those saying no harm can be done to a helicopter by "aerobatics" (and what constitutes an aerobatic manoeuvre) might like to read up on this one and think again.
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I think 1.6.31 echos exactly what Tuc has been going on about for years on here.
i am wrestling with the term “casual factors”. Does not sound very casual to me.
i am wrestling with the term “casual factors”. Does not sound very casual to me.
I think 1.6.31 echos exactly what Tuc has been going on about for years on here.
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Wow, that took some [speed] reading! Good job by the SI, I think.
As ShyTorque notes above, the 'amendment' of operating limits (90º pitch v. design limit) was an eye-opener.
As ShyTorque notes above, the 'amendment' of operating limits (90º pitch v. design limit) was an eye-opener.
Air Safety Management (or lack of!), pages 132 et sec, is worryingly familiar. Once again we find that most basic requirement of Flight Safety, a reliable and fully functioning reporting system, is conspicuous by its absence. SORs (or whatever we might call them these days) are essential for identifying possible problems so that they can thus be nipped in the bud before they become accidents. We have heard before on this forum how they were one of the first casualties of Haddon Cave's "Savings at the Cost of Safety" following the subversion of UK Military Air Safety by RAF VSOs. It seems that the RAF, the MAA, and the MOD have so far failed to rectify that damage. The result is the presence here of ever more UK Military Avoidable Air Accident threads. Mercifully this one merely cost treasure rather than life.
Regulation must be independent of the operator. Investigation must be independent of both operator and regulator. Until that happens the MAA will be committed to the falsehood in the Nimrod Report that Air Safety was compromised in the 90s rather than the 80s, and thus RAF VSOs were uninvolved. Until that bullet is bitten we must expect more avoidable accidents and more needless loss of life.
Regulation must be independent of the operator. Investigation must be independent of both operator and regulator. Until that happens the MAA will be committed to the falsehood in the Nimrod Report that Air Safety was compromised in the 90s rather than the 80s, and thus RAF VSOs were uninvolved. Until that bullet is bitten we must expect more avoidable accidents and more needless loss of life.
Once again we find that most basic requirement of Flight Safety, a reliable and fully functioning reporting system, is conspicuous by its absence. SORs (or whatever we might call them these days) are essential for identifying possible problems so that they can thus be nipped in the bud before they become accidents.
There must be a papertrail,showing `who,and why the RFM limits were changed...? Who signed off the RTS...? Was it QQ,or someone/somewhere else in MOD...?
Sycamore
The Assistant Chief of the Air Staff signs the RTS. The SI gets seriously mixed up in this area, saying the RTS used to be called the Military Aircraft Release. The first time it didn't matter. The second time it did, because it was trying to make sense of responsibilities and got it wrong.
Apart from ShyTorque's observations, what struck me most was the structural integrity discussion. The Panel seemed impressed that structural integrity was managed 'as far back as 1998'. I really think these Panels should be told to read the evidence to the Nimrod Review, at least. Prior to 1992 there was both a Fixed and Rotary Wing Structural Integrity Working Party; the latter chaired by Director Helicopter Projects. These were two of the four major committees that reported to the Defence Airworthiness Group. But then Rotary started doing its own thing, formed the Helicopter Airworthiness Management Group and structural integrity merely became a line item on the agenda. You can do this at a lower level on individual types, but it is a false economy when considering the entire rotary fleet. This background may have helped the Panel explain a few things; such as why the project team was non-complaint on structural integrity, risk recording and ageing aircraft audits, and major risks not tolerable and ALARP.
There's a one-liner (1.4.145) about both Bell and MoD declining to fund research into fatigue. I'd have liked to see a deeper discussion of this. I know what Bell would say, but what was MoD's reason? 'Affordability' is not a valid reason. 'Cost' doesn't explain why the task just didn't proceed. Did someone sign-off to say the risk had now reduced somehow?
A pretty good report, but all very familiar.
The Assistant Chief of the Air Staff signs the RTS. The SI gets seriously mixed up in this area, saying the RTS used to be called the Military Aircraft Release. The first time it didn't matter. The second time it did, because it was trying to make sense of responsibilities and got it wrong.
Apart from ShyTorque's observations, what struck me most was the structural integrity discussion. The Panel seemed impressed that structural integrity was managed 'as far back as 1998'. I really think these Panels should be told to read the evidence to the Nimrod Review, at least. Prior to 1992 there was both a Fixed and Rotary Wing Structural Integrity Working Party; the latter chaired by Director Helicopter Projects. These were two of the four major committees that reported to the Defence Airworthiness Group. But then Rotary started doing its own thing, formed the Helicopter Airworthiness Management Group and structural integrity merely became a line item on the agenda. You can do this at a lower level on individual types, but it is a false economy when considering the entire rotary fleet. This background may have helped the Panel explain a few things; such as why the project team was non-complaint on structural integrity, risk recording and ageing aircraft audits, and major risks not tolerable and ALARP.
There's a one-liner (1.4.145) about both Bell and MoD declining to fund research into fatigue. I'd have liked to see a deeper discussion of this. I know what Bell would say, but what was MoD's reason? 'Affordability' is not a valid reason. 'Cost' doesn't explain why the task just didn't proceed. Did someone sign-off to say the risk had now reduced somehow?
A pretty good report, but all very familiar.
Bing:-
I don't think I've misread it, and the picture it paints is of a dysfunctional system that reports some of the occurrences some of the time. That may fill your inbox, but it doesn't serve the needs of Air Safety.
Either you're misreading it, or my inbox is full of imaginary occurrence reports from across defence.
Of course DHFS had the problem that the contractor was responsible for a far greater proportion of the activity than in more front line operations, the MFTS contract should have had the requirement nailed in from the start.
Tuc,,thanks for that; I`ve been unable to download the SI fully,only occasional pages,and lots of blank ones.
Personally, I think the manoeuvre limits can't just be a max pitch and roll figure - you can create more stress pulling up harshly to 30 deg nose up than you can pulling smoothly to 60 or even 90 - it is the rate of change that does the damage but that isn't factored in to the RFM/RTS.
Nothing wrong with 90/90 as pitch and roll limits - it is how you get there that creates the fatigue.
One solution would be to fit all helos with G meters so at least you have some empirical data to work from rather than just guesswork.
It is the sloping ground landings that will have caused the long term fatigue and the final act of landing out of limits with some less than perfect control inputs as the straw that broke the camel's back.
Nothing wrong with 90/90 as pitch and roll limits - it is how you get there that creates the fatigue.
One solution would be to fit all helos with G meters so at least you have some empirical data to work from rather than just guesswork.
It is the sloping ground landings that will have caused the long term fatigue and the final act of landing out of limits with some less than perfect control inputs as the straw that broke the camel's back.
