Clutha helicopter crash: "... all relevant risks have been identified..."

Dec 12, 2013 80 Replies

Well, one similar helicopter was found to have a warning light fault, in this instance indicating low fuel when the gauges indicated plenty.

That sensor switch might also be able to fail in the other condition, namely not show low fuel when it should do. Add this into a mix where the warning lights come on in normal operation, dependent on fuel level and aircraft speed and attitude - all part of normal operations where the pilot is expected to follow the flight manual and switch transfer pumps on and off - and the absence of a warning light could have a dire effect.

It's interesting to note that increased fuel levels have been put into operation for these aircraft, perhaps in order to avoid a situation where the warning lights come on in normal flight.

I very much doubt it. It will almost certainly be designed to fail safe.

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AIUI that was a temporary precaution by some operators, pending further information on the fault. There has not been an Airworthiness Directive issued, which would indicate a serious concern by the manufacturer or one of the regulatory bodies.

Colin Bignell

On 14/12/2013 16:59, charles wrote: ...

As I said, anything is possible, but any probable reason has to explain why both engines stopped.

Colin Bignell

I'd be very surprised if there wasn't a post mortem carried out. Respect to the families should ensure privacy of any information gained unless there was a real "public interest" reason for releasing a little of it. As the pilots funeral has happened and nothing has appeared I think it's fairly safe to say the pilots health was not an issue.

I could be mistaken, but I thought the post mortem had revealed he was in perfect health before the crash.

In article , Chris Hogg writes

But only you seem to be consistently talking out of your arse .

There are only a very few in this thread or this group who have the knowledge and background to contribute intelligently to this event.

Hair brained, "what ifs" serve no purpose.

Do you really think that *any* posts to this thread serve *any* purpose?

When a clearly knowledgeable individual (eg. one with pilot or relevant engineering experience or one who has performed intelligent research) contributes then there is the purpose (benefit) of education to others. When it degrades to speculation as to whether the coppers in the back were on the piss and a beer can got caught under a pedal then it becomes less so.

If true, that would explain why the post mortem results didn't make the news.

"Crash pilot fit and healthy" wouldn't sell a lot of papers.....

How many stories *do* actually sell papers? Some people buy papers regardless, I've been an "almost never" paper reader for at least a decade, I can only think of one story that's ever made me buy a paper...

I've not seen any reference to a post mortem. I'm not sure they are published in Scotland unless a fatal accident inquiry (equivalent to an inquest in England and Wales) is convened by the Procurator Fiscal.

However, pilots get regular medical examinations and most heart problems will show up at one of those, long before they become a serious problem. In any case, few heart attacks are immediately fatal, so it does not rank highly as a probable cause of the crash.

Colin Bignell

I wouldn't have read it in a paper - more likely to have heard it on the R4 news. It could well have been along the lines of 'After the post mortem, pilot health problems were ruled out' or whatever. Without being specific about the PM findings.

There's commonly some unusable fuel in tanks, because even with downstream filters they don't want to pick up any sediment which might somehow have got in. So the fuel is often taken from just above the base of the tank.

And the precise amount which is unusable is subject to manufacturing tolerances.

I worked on electronics and computers for most of my life. That's why fly-by-wire scares me!

Especially when I read that attempts to produce redundant computer systems using different hardware and software produced by different groups have been unsuccessful when both groups made identical wrong assumptions.

My 15 year old BMW has a readout that tells how many miles before you run

*out* of fuel. And it is accurate to within a couple of miles. If you can do that on a car where it doesn't much matter, surely you can do so on an aircraft, where it does? Obviously using flying time rather than miles.

My jag had one of those. Ran it to -25 miles once.

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In this aircraft, if both supply tanks were full, which they should have been from the amount of fuel drained from the aircraft, there will be at least 83 litres of usable fuel, or about 20 minutes' flying time, as I said.

Colin Bignell

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Colin Bignell

The problem with the supply tanks being full after the crash is that there are internal supply channels that feed them from the main tank under gravity. The helicopter impacted and remained in a heavily nose-down attitude, meaning the supply tanks could have filled up post crash even if they were empty beforehand. It's only usable fuel if it's in the supply tanks. I've already mentioned the complex of warning lights, feed pumps, aircraft speed and attitude that exist in normal flight, and a malfunctioning fuel-level indicator won't help in that regime.

As far as the reported popping and banging is concerned, if No 2 engine had run out of fuel, and the pilot then fed more into its supply tank via the transfer pump, is an air-start possible in these circumstances? Would that account for the noises?

Whilst many heart attacks may not be fatal a large percentage are immediately incapacitating so it cannot be ruled out nor can some other medical problem.

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