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Old 5th Apr 2004, 15:56   #81 (permalink)
 
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Well said Headturner!!

Good words HT - my thoughts exactly!

Nick - thanks for bringing us all down to earth - you are right - people are the most important part of the issue.

Any further news of the crew - heard that P1 was still receiving treatment?

StraightUp - any thoughts from Aussie?
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Old 5th Apr 2004, 16:37   #82 (permalink)
 
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An unproven helicopter is 'Unproven'.
Rignt. And therefore we should never buy any new helicopter, because it is "unproven," even though it might be better then the "proven" helicopter.

Using that kind of logic, the US Army would still be flying UH-1s, rather than Blackhawks...
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Old 6th Apr 2004, 06:01   #83 (permalink)
 
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The photo on the BBC website looked like a mess, though it was a bit small to pick out any details. I will be interested to read the investigation results when they come out.

I have every confidence that if there is a fleet wide problem, that it can be fixed pretty quickly, but then nobody ever seems to post topics on how well or quick something gets fixed (from any manufacturer), but that's probably just human nature.

I'm glad to see a few drivers here supporting the aircraft, it's nice after seeing/hearing a few second hand comments about how disliked the aircraft is. Any other 101 crew care to comment (especially from the other variants).

My thoughts on the presidential bid can be read on the thread dealing with that topic (lets not turn this thread into a repeat), but I do wonder, out of all the people really pushing for either side and trying to put the opposition down, how many work for the manufacturer. All the people I know who work for one of the companies reckon the opposition is a fine aircraft, but just think theirs is slightly better. Even Nick has posted the traitorous words that the EH-101 is a fine aircraft (or something similar, didn't mean to put words in your mouth Nick). I think the S/H-92 will also be very good and popular, but still support the EH-101 (as an ex Wastelander, and I do have a soft spot for the first helo I ever flew in). I am ignoring the 'unproven' argument, it may end up having problems down the line, no matter how much designing you do, or it may not.

ZH-844 - I had to put the 'Again' on the end of my name, I changed my email address and the system wouldn't let me reregister, so I had to start again. Other than that still doing the SeaHawk thing. I can (and will) apply for citizenship in June. Anything going over your way (PM/email me any interesting news).

Any news on the crew member taken to hospital, hopefully it wasn't too serious and they'll all be up (as in flying) and about quickly.
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Old 6th Apr 2004, 08:56   #84 (permalink)

 
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On the subject of how quick something gets fixed, well, speaking from experience, the Navy don't hang around. They will immediately check the entire fleet, and if it is a fleetwide problem, they will implement a repair / replacement / modification programme in a seaman like fashion, as fast as naval gunfire, but twice as accurate

Maybe things are different now from when I left in 2000, but back then, we moved fast when we had a snag.
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Old 6th Apr 2004, 11:24   #85 (permalink)
 
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One possible thing to learn from this is the value of field experience weighed against the newer testing technologies that are available.

A tail rotor hub cracked, and that the crack progressed to fail the tail rotor, toss some blades and cause the crash. Conventional wisdom says that only time and experience (and crashes) will teach us how to eliminate all these critical component failures.

The newest test requirements that are used for every new helicopter (those designed in the last few years, like S-92 and AB-139) find these weak points before production starts, using induced scratches, dents and flaws on all the important parts to try to cause cracks. If a crack is caused by such a flaw, the part is redesigned by adding material, or by reshaping it until the flaw no longer causes a crack. They say that every critical bit is flawed in every critical area, increasing the number of tests quite a bit.

I saw some slides about this that had been posted, but can't find the pointer to the site.

Last edited by rjsquirrel; 6th Apr 2004 at 18:19.
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Old 6th Apr 2004, 13:14   #86 (permalink)
 
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OFBSLF, Thanks for the point, but I think that you have missed the point.

What I was inferriong was that the Merlin has found a weakness in a system that all the previous testing was unable to detect. Now that it has occurred, a fix will found.

The S92 has no in srevice time, so I think it is reasonable to expect that there will be some fix required to some critical part at sometime because no matter how much testing is done, something will turn up. Past experience qualifies this assuption.

Using this as a logical base, the US101 must be 'better' than the S92.

To my knowledge there has never been a helicopter built that hasn't had numerous modifications/fixes to solve subsequent problems. Why should the S92 be different?
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Old 6th Apr 2004, 15:50   #87 (permalink)
 
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Head Turner, I think you have made my point for me, again.
Quote:
Using this as a logical base, the US101 must be 'better' than the S92.
The UH1 has far more in-service time than the EH101, so using your logic, it is therefore "better" than the EH101.

Older isn't necessarily better (nor is older necessarily worse).

I'm sure that the EH101 is a fine machine. Yes, it is a more mature program than the S92. Does that maturity mean that the EH101 is better than the S92? Of course not. Does the fact that the S92 is newer than the EH101 mean it is better than the EH101? Of course not. The EH101 may be better than the S92 (or vice versa), but maturity alone cannot be the yardstick.

Frankly, I don't know which is the better helicopter. I do not have the expertise to make that determination. Nor do I work for Sikorsky or any other company likely to benefit from this contract.

But asserting that the EH101 is better because it has been around longer is nonsense.

If you believe the EH101 is better, then show me some facts and figures. What are the expected mission profiles? What are the comparative capabilities when flying those profiles? Compare payload, range, cost (purchase and operating cost), etc. Compare the safety and combat survivability features of the two.

The presidential helicopters are frequently transported via US transport aircraft. Compare and contrast the ability to transport the EH101 and S92 on C5 and C17 aircraft. Can they both fit? What preparation/completion is required to do so?
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Old 6th Apr 2004, 16:16   #88 (permalink)
 
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Extract from PA News report
Quote:
Military Helicopter Flights Banned after Crash

Restrictions were today in place on the flying of military Merlin helicopters following a crash at a Royal Navy base.

Until investigators determine what caused the accident, Royal Navy and RAF Merlin helicopters will be restricted to life-saving and high priority combat operations.

A spokesman for the Ministry of Defence said it was routine to place limitations on the flying of aircraft after a crash.
He added: “Until we find out what the cause of the accident was, we need to protect the people flying them.
“It will have no impact on current operations. But we are aware that by doing no training we get loss of skills for our people, so there is some impact on long term capability.”

None of the crew members’ injuries in last week’s crash were life-threatening, but one of the two pilots was airlifted to the Royal Cornwall hospital, where he is still recovering.

Initial investigations suggest that there was a problem with the helicopter’s tail rotor, the MoD spokesman said.

This is only the second time that a Royal Navy Merlin helicopter has crashed. The previous accident occurred in October 2002, off the Isle of Skye.

The Royal Navy has 42 Mark One Merlin helicopters and the RAF has 22 Mark Three Merlins.
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Old 6th Apr 2004, 17:32   #89 (permalink)
 
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One of the big problems with the Merlin/101 is the extensive use of composite materials - yes they are light and strong but, unlike metal components, there is no Non-Destructive Testing technique for assessing possible damage/failure of components. The crack in the TR at Culdrose was known about and being monitored - just as well they didn't leave it too late then!!
In the bad old days, aircraft were built and tested in role and failures occurred and were rectified (often after loss of life) - are you telling me we should still accept such risk? Are Airbus going to release their new double decker monster plane until it has been exhaustively tested and proved safe for public transport? I don't think so, the negative PR of killing 500 plus passengers in one go would preclude that. But, are Westlands happy to convince the military that they have an airworthy aircraft, despite some high profile failures so that jolly jack tar and the rest of the cannon fodder in the military can play crash test dummies for tthe R & D dept? it would seem so.
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Old 6th Apr 2004, 23:08   #90 (permalink)
 
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Exclamation hold on a minute

Being associated with WHL I think the insinuation that WHL are putting pople lives at risk intentionally because they can't be bothered to do anything else is a slanderous accusation without any evidence at all and I hope CRAB will retract that immediately

The cause of the crash and factors leading to it ARE NOT YET KNOWN BY ANYBODY, the BOI has convened, WHL are no doubt helping as much as they can, in short CRAB and everybody else is not speaking from a position of knowledge and anything that says otherwise here is wrong.

Any cracking may or may not be a causal factor it is far too early to tell so let's let the people do their job and report back when the FACTS not the speculation are in.

BTW CRAB you really should get some NDT training before spouting off like that.

Sorry but the previous post went too far

DM
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Old 6th Apr 2004, 23:49   #91 (permalink)

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To: rjsquirrel

Quote:
A tail rotor hub cracked, and that the crack progressed to fail the tail rotor, toss some blades and cause the crash. Conventional wisdom says that only time and experience (and crashes) will teach us how to eliminate all these critical component failures.
If a proper engineering program is initiated it will include Product Integrity analyses which includes an FMECA. The purpose of the FMECA is manifold in that it identifies all potential failure modes and the resultant effect of those failures. The FMECA also is used to create the troubleshooting procedures relative to the identified failures. The severity of the failure and its’ effect will identify to engineering and the test engineers what should be tested and what may have to be redesigned in order to eliminate the effect as well as the failure. A properly executed FMECA will encompass all of these elements. However in this case the FMECA was just executed.



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Old 7th Apr 2004, 05:20   #92 (permalink)
 
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Dangermouse - you read into my post what you wanted to, I am not going to write 'allegedly' everytime I voice my opinion on something (and I think it would be libellous not slanderous).
If the BOI finds that it was not cracking of the TR hub that caused the accident then I will eat a double helping of humble pie. However, since a fleet-wide check of the TR hub was instigated straight after the crash, and the worldwide fleet remains grounded except for urgent ops and lifesaving, and the grapevine alleges that several other aircraft in the fleet have cracks in the same area as the crashed one - what is one supposed to think? Gremlins????
Would you like to detail the NDT procedures for composite materials, other than a visual inspection or by tapping the item (Lynx MR blade), so that I can be enlightened?
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Old 7th Apr 2004, 18:30   #93 (permalink)
 
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fish EH101 Merlin

A RW colleague of mine on another forum said we need a thread on how good the Merlin HM 1 is and why all us operator types like it so much.

Well in these times of rumour and counter-rumour especially from those who want to kill off other peoples projects I will start. Of course there will be the detractors but I'm sure we can guarantee they aren't Merlin orientated or have ever been closer than watching a flypast.

The aircraft is much better than the Sea King it replaces - more space, better radar , sonar and other kit.

It flies very much like a Lynx and around the flight deck whether its at night or in poor weather its a complete dream to handle.

Its fast and smooth - senior officers love to be transported in it.

On a frigate its like having and airborne ops room, SH helo and ASW aircraft all in one. It can do all these things at once without serious limitation to the other roles.

Despite what you might believe or have been told its an epic SAR platform.

You may wish to disagree with me on serviceability or the like but thats not an inherent aircraft design issue - its the support/stores contract that was put in place by our friend Mr Portillo in 1993/4. Funny how the Conservatives forget all their best decisions.

Costs - all costs of aircraft these days relate to total aircraft PROGRAMME costs - including design support and simulators etc. I guarantee you that is not the case when you compare with other aircraft and how much are Nimrod MR4s a piece?

Finally - if you want to really comment on Merlin. Travel SW and visit Culdrose - get in one (or even see the sim) - and decide objectively for yourself.

I expect someone will bring the accident up in this thread - DON'T!, wait for the BOI.


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Old 7th Apr 2004, 18:54   #94 (permalink)
 
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I reiterate

NO ONE KNOWS WHAT THE CAUSE WAS , as I said before any cracking may or may not be a causal factor, nodody knows yet and wild guessing now doesn't help

I believe the aircraft in Italy are still flying, no aircraft are actually grounded (which is in itself a very emotive term) as the Airworthiness certificates have not been withdrawn, they are still available to fly if required.

It is widely overlooked that the aircraft is CAA, RAI and FAA compliant with the requisite rules and therefore any safety case must have been carried out to the certification authorities satisfaction. Obviously it is possible something has been overlooked but the job was done competently enough that all parties were happy, after all the RAF, RN, MMI, CAF, FAA, CAA, RAI and Japanese authorities must have been happy to allow the aircraft to fly. Still nobody is perfect (even Lu must admit to that).

For Crab to say 'But, are Westlands happy to convince the military that they have an airworthy aircraft, despite some high profile failures so that jolly jack tar and the rest of the cannon fodder in the military can play crash test dummies for tthe R & D dept? it would seem so.' is pretty blatant.

for NDT, what about thermal profiles, X rays, ultrasound?
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Old 7th Apr 2004, 19:51   #95 (permalink)
 
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Quote:
Finally - if you want to really comment on Merlin. Travel SW and visit Culdrose - get in one (or even see the sim) - and decide objectively for yourself
If only they'd let me fly the bloody thing. Yes it is neat, fast, commodious and appears to do everything comfortably.
My criticism is not with the machine, but the machinations behind it's development and introduction. In '84 it started out at £12.5M, and as usual has gone way beyond anticipated costs. Unfortunately from what I see and understand the aircraft is under supplied with spares, which must be a tragedy for those trying to introduce it to service.
Glad to see you chaps enjoy the beast.
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Old 7th Apr 2004, 21:42   #96 (permalink)

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To: Dangermouse

Quote:
Obviously it is possible something has been overlooked but the job was done competently enough that all parties were happy, after all the RAF, RN, MMI, CAF, FAA, CAA, RAI and Japanese authorities must have been happy to allow the aircraft to fly. Still nobody is perfect (even Lu must admit to that).
The only documentation provided to the certification authorities for their evaluation relative to certification are the engineering test reports that show compliance with the certification requirements and the Safety Hazards Analysis. The manufacturers do not provide the FMECAs to the authorities unless they ask for them and then they must come to the manufacturers to view them.

The safety analysis reflects the FMECAs so if no catastrophic failure modes are included in that analysis then there are no catastrophic failures considered in the Safety Hazard Analyses.


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Old 7th Apr 2004, 21:51   #97 (permalink)
 
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I walked up the ramp on one in the hangar the other day. I am only 6' tall in my boots and could not stand upright. I was not wearing a bonedome. Would it have been that difficult/costly/impractical to have the cabin 6" higher. It must be murder on the back of the poor bloke who spends his time wandering around in the back.

In general; why do you bother with retractable wheels on choppers. With your limited speed I wouldn't have thought the weight/complication penalty was worth it

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Old 7th Apr 2004, 21:57   #98 (permalink)
 
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Merlin threads are prone to be troublesome because some of us are talking about the Grey Navy ones, others about Green RAF ones....

Last edited by WE Branch Fanatic; 7th Apr 2004 at 22:36.
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Old 7th Apr 2004, 22:13   #99 (permalink)
 
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Marlin threads are prone to be troublesome
Why do the RAF have green fish and the RN grey ones?

We're occasionally visited by Merlins at the plc (useful for drying the outfield on the cricket pitch). Mighty impressive beasties. Although whether one was required to deliver an A4 sized package to an ICSC inmate might be debated....

Last edited by Archimedes; 7th Apr 2004 at 22:35.
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Old 7th Apr 2004, 22:51   #100 (permalink)
 
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Unhappy I'll concede that one

Not being a system safety expert I have to concede that point


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