BA engine issue at Heathrow

[TSR2]

Hi George,

Yes, my wife said the same thing, but apparently not.

Hi Garry,

Yes, that's the photo that was posted hear some years back, I think it was a US air flight if memory serves.

[speedbird591]

One would gave thought there would be a tell-tale for the cowl doors?

I agree, George, after so many instances of this it seems that relying on human visual checks isn't reliable enough.

The photo on page three of the AAIB report, linked to by Ian, shows how it should be easy to spot on a pre-flight check even without squatting down to look at the latches. There's a visible gap between the cowls and the casing when the latches aren't fastened.

It seems to suggest that 2 or 3 people haven't done their job properly. The engineer that closed the cowls, the supervisor who signed off the job and the pilot who did the pre-flight walk round.

If it's possible for three professionals to overlook the same visible fault then relying on a visual check is insufficient.

My dear late Dad had an old cooker with a glass covered electric hob and it wasn't always obvious that it was switched on and easy to try and use as a work surface without realising it was hot. So he rigged up a Heath Robinson warning light above it with a big red bulb so you could tell if the hob was on. It didn't look pretty but it did the job. Perhaps he should have designed warning devices for Airbus

Ian

[Chris Trott]

Having worked around the planes and seen the cowlings being undone, they are a real bastard to work with. The Airbus design is very hard to adjust for proper tightness and I have watched latches come open on pushback. I'm not saying that's what happened here, but it contributed or was the cause of at least one or two of the previous occurrences. Part of the problem is that there's no "over-center" protection or mechanical safety on these latches. They are held closed simply by friction against the other cowl when properly adjusted. You then put a screwdriver into a slot in the latch to pry them open. They've had a similar problem with the fuel panel latches for the same reason, including having at least one aircraft loose a section of leading edge on approach due to a fuel panel that opened in flight.

[Garry Russell]

It seems then that whatever happened here or how and why it happened is detail, but it sounds like there is a general problem here waiting to happen.

Extremely lucky that the aeroplane landed safely. It can only be imagine what the outcome would be if both engines had failed or a cowl had compromised a tail plane let alone what would happen if debris hit people on the ground.

I hope they treat the safe landing as a bonus and act as if it had been a disaster and take immediate steps to ensure this can't happen again

The A.320 and the engines are complex pieces of engineering so I'm sure they can design a latch that is fool proof, but often the simpler things are skimped on.

But for now they should think of the news stories that would have reported that the airliner that crashed on a residential area shortly after take off form Heathrow killing hundreds was caused by simple latches on the engines being left undone.

Well it didn't happen, but it is a serious as if it had.

[Dev One]

If thats the case Chris I'm very surprised that they have gone on so long without a redesign. It could be that the French want to do it differently, but whats wrong with the old fashioned 'King' type latches that do have a secondary tab for locking?
Keith

[TSR2]

Duck Tape

[airboatr]

Anyone here ever actually put their meat paws on the "latch" in question, repeatedly , as in
It was something they were trained to do and did for a living.
I'm curious does the latch have tension on it when locked or is it more of a twist lock after the cowls are mated

The one pic I've been able to get off the internet shows the "thumb lever of the latch hanging down in the unlatched position.
and as the "Ian's" have mentioned shows the cowl ajar from it's fitted resting place.
http://www.aviationweek.com/Portals/AWe ... _cowls.jpg

I have to say,.. this had happened 32 times? as of 2012..

Something very hinky going on.

[NigelC]

I have to say,.. this had happened 32 times? as of 2012..

Something very hinky going on.

Out of 5.500 aircraft in service, with over 50,000,000 flights under their belt in 25 years of operation.

So this has not occurred on over 49,999,968 departures when, following the FCOM pre-flight checks, the crew member doing the walk round has ensured FAN COWL.........CLOSED/LATCHED.

Shouldn't happen but did happen, but there's nothing wrong with the latches. this is not happening every day.

If the correct procedures had been followed, then this would not have happened. Be it engineers/crew not following correct procedure or the procedures themselves not being robust enough, it is a procedural problem, not an airframe problem. That, by no means, does not exclude changing the design of the latches to reduce the risk of the procedure, but there is already a secondary latch mod available for the V2500 fan cowl.

Let's just remind ourselves of the facts. That aircraft was perfectly serviceable, there was nothing wrong with it until the cowls departed, and the cowls departed because they had not been fastened as was supposed to happen after the IDG oil level checks had been completed, which should be subject to dual inspection and signature/stamp, the fact they were not fastened was not seen by the flight crew during pre-flight checks in which it is an item, and the pushback crew, who should complete a last minute check for hatches/panels failed to notice it.

THE LATCHES WILL NOT WORK IF THEY ARE NOT LATCHED. Doesn't matter if you change the design. that fact does not alter.

N

[TSR2]

Must agree Nigel, unless there was a significant mitigating circumstance in this instance, its evidence of the failure of several people to follow the basic checks. Sure things can be made easier for people, but as can be seen in so many different areas today, when you dumb things down to such a level that any idiot can do it, that's exactly what you get, any idiot doing it, without any care or attention to detail.

[Chris Trott]

Nigel - not disagreeing that this case was one of human error. However, the design is also suspect as it has been faulted in at least one other case as it lends itself to being an issue. What we don't know here is whether there was an issue and the mechanic who performed the IDG check reported it or not. This is the question I have. As these latches will not work if not properly adjusted, it is possible that the mechanic encountered a problem when attempting to re-latch the cowlings and reported it for further action and that action wasn't taken.

I've watched these latches fall open on their own a few minutes after the mechanic walked away because they were too loose and I've watched them be impossible to close because they were as little as 1 thread turn beyond "correct tension" because the "tension springs" that are in the latch have almost no compression to them so there is little forgiveness.

I helped on several occasions close cowlings when I was fueling as I was the only guy available on the ramp who could spare 10 seconds to do it. The latches have tension on them yes, but the tension is constant from when the cowls touch to when the latch is flush with the cowling. There is no "over center" point where you get a slight release of tension as the latches go flush as you do with other manufacturers. You also don't have any secondary mechanical latch to help hold the latches closed. It is purely held there by tension. When properly adjusted, it works fine. The problem is that the tolerance for "properly adjusted" is very small, which lends itself to failure. As Nigel said, if there's only been 32 failures that's a very small number, but then again, for a major component like a cowling, that's an unacceptable number. It also doesn't account for the number of times a plane arrived with one or more latches "unlatched" due to this problem but there was no separation of the cowling and it didn't get reported as a "mishap" or even a maintenance item.