OT Clutha pub helicopter crash: engine failure

[newshound]

The procedure says something like "ONLY IF PRACTICABLE"

[Terry Fields]

The overall mystery here is why an aircraft with sufficient fuel on board suffered a double engine failure.

With that in mind, one has to look as what was done, and what was not done, on board the aircraft at the time. There appears to be, so far, only examples of what was not done, and I mentioned the XFER pump switches, the blade pitch (suggested by the non-rotation at the time of impact), the emergency light switch, and radio calls. With the little that is published so far, the only common factor appears to be some form of incapacitation of the pilot. If any one of the actions mentioned had been performed, it would have proved the pilot was functioning. Of course, the reverse case doesn't prove the pilot wasn't functioning, but then one has to look elsewhere for an explanation of why the things mentioned weren't done, by someone with considerable experience.

[The Natural Philosopher]

I somewhat agree

[Johny B Good]

The report, at this stage, does rather suggest 'Pilot Incapacitation', which leaves me to speculate, as you have done, as to what could have caused such incapacitation.

It too occured to me about the possibility of a ground aimed high power laser pointer blinding the pilot but I'd have thought the pilot would have radioed this event in to ATC and asked his two observers to operate or assist him in setting appropriate switches if this had happened a few minutes before the engines flamed out. The laser pointer blinding scenario only looks plausable if the blinding took place within seconds of the flameout,( i.e. very unfortunate timing).

Another possibility is the pilot suffering a massive heart attack or a stroke, but the autopsy should have revealed this (and any retinal damage) by now if either had been the case so it still remains a mystery.

If the helicopter had been equipped with a CVR, we may have had all the answers long before now. In view of the nature of these flights, we may well see CVRs becoming a mandatory requirement in the not too distant future.

Thus far, all the indications suggest that the pilot was incapacitated in some serious way. There simply doesn't appear to be any reasonable explanation as to how this could have happened. In the end, speculation may well prove to be all that's left to the AAIB.

[Dave Liquorice]

But some form of incapacitation that still enables him to fly the aircraft long enough for the supply tanks to become empty...

I'm not a pilot but I suspect that a helicopter won't fly itself. If you stop giving the minor little tweaks to the controls the craft will fairly quickly (seconds, tens of seconds) get out of control.

[Jim Hawkins]

Does a single fuel pump supply both engines ?

Jim Hawkins

[Nightjar]

Police helicopter pilots are among the most experienced around. They need to fly in conditions that would keep many other helicopters grounded. While anybody can make an error, for a pilot of that level to make two cumulative errors is unlikely. Three or more, as would be required here, is starting to stretch the bounds of credibility.

Colin Bignell

[Johny B Good]

Well, if it was a 'Medical Emergency', my money would be on him having suffered a stroke which might have left in paralysed and unable to give instruction to his 'observers' whilst allowing him just sufficient control to maintain attitude until the flameout.

It could have happened just prior to the need to switch the transfer pumps on - again just bad timing perhaps. Anyway, that's just pure speculation in the absence of autopsy findings that could provide evidence of such a trauma.

[Davey]

There is a link in here somewhere to a forum discussion that includes a diagram of the fuel system. Each engine has its own tank and pump, both of which are fed from the main tank.

[tony sayer]

In article , Johny B Good scribeth thus

I am not a neurosurgeon;! ..

But what in an autopsy could you find as evidence of that happening?.

It doesn't take a lot of force to form a hematoma in the brain and the resultant cash must have coursed more then a few odd bruises.

Be that an infarct or bleed..

But the more I read of it the more it does look like a rapid pilot problem.....

[Tim+]

What I can't get my head around is why such a daft fuel system was ever considered safe in the first place?

Would you buy a car that required you to fiddle with fuel pump switches regularly to stop the engine cutting out? Of course not, not even bearing in mind the lack of lethality of the consequences. Now a helicopter is incredibly dependant on continuous power and yet a simple yet absolutely vital mechanical task is left up to a bit of soggy human firmware. Basically, the system strikes me as an accident waiting to happen.

I sure there were good reasons why the fuel system evolved like that but surely to god in this day and age we can devise a better system that isn't reliant on pilot input?

Tim

[Tim+]

I was in Nottingham at the time of the Kegworth crash. The pilot was lauded as a hero for ages as nobody wanted to believe that a pilot (with a co-pilot on board too) could do something as stupid as shut down the wrong engine, but he did.

This kind of stuff happens, frequently.

Tim

[Nightjar]

That was a logical decision, based upon the information available to the pilot at the time. He was flying a newly acquired aircraft and did not know that Boeing had changed the distribution of air from the engines, which meant that the area with smoke in it was not fed from the right hand engine. Even so, it was a single error during an emergency, which is understandable. In the case of the Clutha helicopter crash, the pilot would have needed to make at least three serious and cumulative errors, which is not very credible for a pilot with his experience.

Colin Bignell

[John Williamson]

I suggest that you read pages 97 onwards of the AAIB report, which list the multiple errors that the flight crew made in reacting to problems which were correctly recorded by and displayed on the instruments in the case of the Kegworth crash. To put it bluntly, they panicked.

The effect was simple, in that the wrong engine was shut down, and they

*nearly* managed to land safely, but a number of errors were made by both members of the flight crew.

[Flooded Out]

There is no stretch of credibilty required

One operator error, the failure to switch on a transfer pump following the previous transition from hover to high speed forward flight - certain flight attitudes require no pumps, the indicatons of fuel levels and alarms are critical in prompting the use of the transfer pumps.

Multiple system failure of fuel level indicators and level alarms, which since the event have been subject to mandatory checks where a number have been found to be faulty.

The AAIB need to prove it, which may prove difficult, but it is IMHO almost a closed case given the content of this latest bulletin, the post event actions of Eurocopter / Airbus Helicopters, the results of those checks and the modification to the fuel management procedures

At 1000ft, in well away from large fixed wing aircraft flight paths there is nothing to affect the airflow If there had been evidence of bird strike, or debris ingestion causing ignition failure then by now they would have reported it.

No fuel in both engines makes both stop. Failure to maintain rotor rpm during the period immediately after those engine failures makes the aircraft fall out of the sky. Hitting the ground at speed is usually fatal

[Nightjar]

On 16/02/2014 09:31, Flooded Out wrote: ...

SFAIK, only one has actually been found to have given a misleading reading and that still gave the most critical warning.

Colin Bignell

[Nightjar]

On 15/02/2014 18:16, Tim+ wrote: ...

However, car drivers do not get trained to anything like the standards of even a private pilot, nor do they need a constant awareness of where fuel is, how much of it there is and how where it is might affect the centre of gravity and hence the balance of the car. Fuel transfer pumps are not uncommon in aircraft and their use should be automatic to any pilot familiar with the aircraft type.

It would undoubtedly be possible to design a fully automatic fuel transfer system. However, getting it through the approval systems is unlikely to cost less than a couple of million pounds and there is no guarantee that it would do the job better than a human pilot who might have reasons for not moving the fuel in the same way that a computer would. My car has a lot of automatic systems that could make it close to autonomous, but it sometimes reads the inputs wrongly.

Colin Bignell

[Nightjar]

...

Those, however, were consequential errors arising from the initial error in identification of the faulty engine. Without that first error, there would have been no crash.

In the case of the Clutha helicopter crash, pilot error would have required three separate errors to be made, all of which needed to occur for the accident to happen as it did.

Colin Bignell

[Tim+]

Interesting that some pilots have admitted to just leaving the transfer pumps running all the time on this helicopter which would suggest that the CofG problems are minimal and that having to switch pumps on and off is perceived to be at the very least, a pain, at worst, a potential cause of avoidable fuel starvation.

Tim

[John Williamson]

Without *all* the crew's mistakes occurring in the sequence they did, there would have been no crash. It was the cumulative effect that crashed the plane, not the single mistake that you are blaming.

And in the case of the Clutha crash, how do you know that the chain of errors didn't follow from a single cause, as you claim happened at`Kegworth?

The AAIB don't admit to knowing the cause yet, so maybe you have inside information?