Qantas A380 uncontained #2 engine failure
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Yes, we're talking about 57 seconds from first start of value changes up to total engine disintegration. Not much time indeed.
Still one would expect with the pure volume of changes in the engine the FE would trigger a clear enough warning to take a look at this immediately.
Still one would expect with the pure volume of changes in the engine the FE would trigger a clear enough warning to take a look at this immediately.
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Still one would expect with the pure volume of changes in the engine the FE would trigger a clear enough warning to take a look at this immediately
NoD
Edit: Most changes seem very minor. At 10s to "thrust drop" N3 Vib goes up markedly, but I have no idea of the units / if in limits. The OilT/P variations are small, and again, suspect in limits. N1/2/3 again fairly small.
Bear in mind that even with a Fire Warning, probably the only "do something farily quickly" drill, in many cases it would be 10s+, and possibly 30s, before the first aciton (closing TL) would be taken by a crew.
Last edited by NigelOnDraft; 3rd Dec 2010 at 08:47.
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Quote: "ECAM messages......"
I think there should be a few gongs being awarded to the crew. Not quite clear though what awards are given for civilian aircrew who achieve the almost-impossible.
By the way, did they pass their line checks?
Jack
I think there should be a few gongs being awarded to the crew. Not quite clear though what awards are given for civilian aircrew who achieve the almost-impossible.
By the way, did they pass their line checks?
Jack
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This is a philosophical point which will not have escaped professional pilots and design staff, but I make no apology for spelling it out in its full simplicity.
Many thousands of highly educated aerospace engineers have put immense amounts of effort into making the aircraft multiply redundant and failure-tolerant so that any one failure or set of failures can be survived.
Yet a single component failure in an engine caused such a massive event that the multiple systems in the aircraft were disabled to an extent that came very close to disaster and it took very skilful and highly discilplined management to salvage the situation.
Is there a cultural difference between airframe and engine manufacturers and is there any way that the gap can be bridged? Or is it a simple and necessary fact of engineering that engines of this power and thrust cannot be made safe in the same way that airframes are?
Many thousands of highly educated aerospace engineers have put immense amounts of effort into making the aircraft multiply redundant and failure-tolerant so that any one failure or set of failures can be survived.
Yet a single component failure in an engine caused such a massive event that the multiple systems in the aircraft were disabled to an extent that came very close to disaster and it took very skilful and highly discilplined management to salvage the situation.
Is there a cultural difference between airframe and engine manufacturers and is there any way that the gap can be bridged? Or is it a simple and necessary fact of engineering that engines of this power and thrust cannot be made safe in the same way that airframes are?
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Nigel, you sound like another Nigel I know, must be something common in the name, 'cus neither of you seem to understand the thought process differences between pilots and flight engineers.
I'm betting you've never flown in a three-man crew environment!
WTF...30 sec after a fire warning to close the thrust lever....
I would have expected the FE to simultaneously advise the Captn of the indications, and be slowly retarding the power, I say slowly because of the phase of flight they were in, as well as selecting maximum power on the other three engines.(At that stage I expect that climb power would be set!)
In the Qantas environment, all the FEs would be familiar with the RRs, since they would have been operating RB211s for most if not all their career.
Hence the caution with the stated RPM variations.
RRs are complex engines and subtle indications are not to be taken lightly!
EW73
I'm betting you've never flown in a three-man crew environment!
WTF...30 sec after a fire warning to close the thrust lever....
I would have expected the FE to simultaneously advise the Captn of the indications, and be slowly retarding the power, I say slowly because of the phase of flight they were in, as well as selecting maximum power on the other three engines.(At that stage I expect that climb power would be set!)
In the Qantas environment, all the FEs would be familiar with the RRs, since they would have been operating RB211s for most if not all their career.
Hence the caution with the stated RPM variations.
RRs are complex engines and subtle indications are not to be taken lightly!
EW73
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EW73...
You are right, I have never flown 3 crew, hence the "caution" in my statement. But are you really saying, maybe on a twin, with a Fire Warning at V1, the FE will be pulling the (a?) TL back (unmonitored?), while the aircraft is still taking off / rotating?
Or would there be a CRM / team discussion about the indications, after establishing a safe flightpath, a diagnosis, decision, and then decide who will do what (drills, QRHs, memory etc.).
I would still challenge an FE, on a 14 hour flight, to pick up with a 50%+ chance, in any 10s period, those indications, diagnose and action something in time to prevent the disintegration
NoD
You are right, I have never flown 3 crew, hence the "caution" in my statement. But are you really saying, maybe on a twin, with a Fire Warning at V1, the FE will be pulling the (a?) TL back (unmonitored?), while the aircraft is still taking off / rotating?
Or would there be a CRM / team discussion about the indications, after establishing a safe flightpath, a diagnosis, decision, and then decide who will do what (drills, QRHs, memory etc.).
I would still challenge an FE, on a 14 hour flight, to pick up with a 50%+ chance, in any 10s period, those indications, diagnose and action something in time to prevent the disintegration
NoD
This is a philosophical point which will not have escaped professional pilots and design staff, but I make no apology for spelling it out in its full simplicity.
Many thousands of highly educated aerospace engineers have put immense amounts of effort into making the aircraft multiply redundant and failure-tolerant so that any one failure or set of failures can be survived.
Yet a single component failure in an engine caused such a massive event that the multiple systems in the aircraft were disabled to an extent that came very close to disaster and it took very skilful and highly discilplined management to salvage the situation.
Many thousands of highly educated aerospace engineers have put immense amounts of effort into making the aircraft multiply redundant and failure-tolerant so that any one failure or set of failures can be survived.
Yet a single component failure in an engine caused such a massive event that the multiple systems in the aircraft were disabled to an extent that came very close to disaster and it took very skilful and highly discilplined management to salvage the situation.
Kudos to all I say. Pilots, CC, ATC, Airbus etc.
Mistrust in Management
EW73
I would have expected the FE to simultaneously advise the Captn of the indications, and be slowly retarding the power, I say slowly because of the phase of flight they were in, as well as selecting maximum power on the other three engines.(At that stage I expect that climb power would be set!)
It's as NoD says really in all airlines I've flown for.
Individual crew members should not take action that may affect the safe flight path of the aircraft unless that action has been agreed by the Captain, and furthermore any such action should be carefully monitored by another crew member.
Regards
Exeng
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Hats off to those in the cockpit
I'm not a pilot but a flyer. The media often portray modern aircraft as being so automated they don't really need pilots anymore. Sure computers can help iron out human error and make some things easier. But when you read the report and the huge list of issues the crew were facing, it's quite humbling. One can only imagine what was going through the mind of the Capt with the autopilot disengaging with such a short distance to go, manually landing a massive aircraft knowing there were braking/reverse thrust limitations, queries over landing gear, uncertainty about other damage etc and knowing you have 450 people behind you. I do hope that not only Australia but other countries including the UK who had people on board that flight see fit to award this crew appropriately. The word 'hero' is perhaps over used these days and I'm sure the guys would say they were just doing their job. But they averted an horrific disaster.
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How many HS's do you have, and how well can you fly if one falls off ? How many main wing spars ? Your cargo door seals itself when the fuselage is pressurized - or is it just held closed by a latch (I mean, why on earth would an airframe engineer do that and not use a plug-door?), and what if that latch, or its controller, fails ?
Or even just the control surfaces. Say, uncommanded rudder hard-over. Your airframe designers would have ensured no single point of failure could cause that, or that the other control surfaces were sufficient to allow the pilot to handle it, right ? Or if, lets say, they used a jackscrew assembly that was a single point of failure, then they'd make sure that jackscrew was itself failsafe with redundancy (like NASA did), right ?
Reality is that no airframe or engine that is completely redundant and failure tolerant would ever get off the ground (literally). Safe, but useless. Engineering compromises have to be made, and sooner or later one of those will kill. The aim is to make it later rather than sooner, but engineers, like pilots, are human and don't always get it right.
Final note: IMO in any branch of engineering, any belief that you have elimiinated the possiblity of failure ["any one failure or set of failures can be survived"] is asking for a swift kicking from Mr Murphy & Laws...
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The issue of redundancy was raised early in this thread, by several posters, in a thoughtful, questioning (and polite!) manner. A few responded helpfully, but a similar number were "somewhat" dismissive of the idea that there may be a fundamental flaw, either in concept or design (or a combination of both) which compromises the overall idea of redundancy in this, and other aircraft.
Having monitored the official reports coming out of this accident, it is clear that the spotlight is just as firmly fixed on the "collateral damage" of the engine failure and its consequences, as it is on the engine failure itself.
The spotlight is also beginning to focus on the need for professional aircrew to have the skills and capacity, individually and as a crew, to deal with any eventuality thrown their way.
Both of these outcomes are very good news for the avaition industry.
Absolutely, anybody remember the ship...what was the name...Titanic??
Having monitored the official reports coming out of this accident, it is clear that the spotlight is just as firmly fixed on the "collateral damage" of the engine failure and its consequences, as it is on the engine failure itself.
The spotlight is also beginning to focus on the need for professional aircrew to have the skills and capacity, individually and as a crew, to deal with any eventuality thrown their way.
Both of these outcomes are very good news for the avaition industry.
Final note: IMO in any branch of engineering, any belief that you have elimiinated the possiblity of failure ["any one failure or set of failures can be survived"] is asking for a swift kicking from Mr Murphy & Laws...
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It would seem that RR are not the only with oil pipe problems....
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2010-0725; Directorate Identifier 2010-NE-18-AD];
Amendment 39-16528; AD 2010-24-09]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires a one-time visual inspection of the No. 3 bearing oil pressure tube, part number (P/N) 51J041-01, P/N 50J604-01, or P/N 50J924-01. Tubes that are found cracked or repaired must be removed from service. This AD also prohibits repaired tubes from being installed. This AD results from one report of a repaired No. 3 bearing oil tube that caused an engine in-flight shutdown, seven reports of repaired No. 3 bearing oil pressure tubes found cracked that led to unscheduled engine removals, and one report of a test cell event from a repaired tube that cracked. We are issuing this AD to prevent cracking of No. 3 bearing oil pressure tubes, which could result in internal oil fire, failure of the high-pressure turbine (HPT) disks, uncontained engine failure, and damage to the airplane.
DATES: This AD is effective December 28, 2010.
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2010-0725; Directorate Identifier 2010-NE-18-AD];
Amendment 39-16528; AD 2010-24-09]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires a one-time visual inspection of the No. 3 bearing oil pressure tube, part number (P/N) 51J041-01, P/N 50J604-01, or P/N 50J924-01. Tubes that are found cracked or repaired must be removed from service. This AD also prohibits repaired tubes from being installed. This AD results from one report of a repaired No. 3 bearing oil tube that caused an engine in-flight shutdown, seven reports of repaired No. 3 bearing oil pressure tubes found cracked that led to unscheduled engine removals, and one report of a test cell event from a repaired tube that cracked. We are issuing this AD to prevent cracking of No. 3 bearing oil pressure tubes, which could result in internal oil fire, failure of the high-pressure turbine (HPT) disks, uncontained engine failure, and damage to the airplane.
DATES: This AD is effective December 28, 2010.
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Knowledge of the consequences of a failure of a component leads to design decisions concerning that component including consideration of the use of redundant systems. If redundancy is not feasible the components are designed with larger safety factors.
In the special case of a manufacturing defect the design logic is overridden and so safety depends on the ability to trap the defect during inspection and assembly.
The fact that the error was not detected in the normal course of manufacture does not imply that corrections to the aircraft systems are appropriate. The rule is “if it aint broke don’t fix it.” In my opinion, this accident does not indicate a problem with the design of either the aircraft or the engine, but is only a manufacturing issue.
But suppose you go and change something because you think that you have spotted a possible weakness. Then ask yourself what are the inadvertent adverse consequences of that change. I doubt very much if you would ever really know that you were better off.
In the special case of a manufacturing defect the design logic is overridden and so safety depends on the ability to trap the defect during inspection and assembly.
The fact that the error was not detected in the normal course of manufacture does not imply that corrections to the aircraft systems are appropriate. The rule is “if it aint broke don’t fix it.” In my opinion, this accident does not indicate a problem with the design of either the aircraft or the engine, but is only a manufacturing issue.
But suppose you go and change something because you think that you have spotted a possible weakness. Then ask yourself what are the inadvertent adverse consequences of that change. I doubt very much if you would ever really know that you were better off.
Last edited by firstfloor; 3rd Dec 2010 at 11:08.
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Is this guy a pilot ?
While I am sure there will be lessons / recommendations, I see nothing in this QF episode to indicate major problems anywhere:
- "Rule 1" Engines should not suffer uncontained failures. Everything in the engine design / manufacturing process / maintenance / operation should be based on adhering to that principle.
- Despite the "rule" above, it appears airframes should be designed with sufficient redundancy to cope with 1 HE fragment.
- In this event, due to "Rule 1" failing, there were 3 HE fragments.
- Despite 3 HE fragments, the aircraft had, and utilised, sufficient redundancy to, fly, diagnose, and plan a safe landing.
- I do not want to take anything away from the crew.... I am sure they did an outstanding job. However, I have not seen any indication that a "typical" competant line crew (of 2) could not have come to a similar "safe" outcome, even if it was less tidy / optimal / timely.
NoD
The fact that the error was not detected in the normal course of manufacture does not imply that corrections to the aircraft systems are appropriate. The rule is “if it aint broke don’t fix it.” In my opinion, this accident does not indicate a problem with the design of either the aircraft or the engine, but is only a manufacturing issue.
If the root cause is that cracked oil tube, I find myself in rough agreement, without the "only" modifier. "Accident does not indicate a problem with the design of either the aircraft of the engine, but is a manufacturing issue." (Exceptions in a moment.)
Manufacturing process issue: when performing a counterbore, ensuring concentricity, true center, etc, are within tolerances and comply with blueprint specifications is a place for RR to sort some things out.
If the tubes aren't cracking when the counterbore is correctly made, then design probably isn't the problem.
There is room for the aircraft manufacturer, however, to review
- the problems with engine control from the cockpit,
- fuel transfer,
- flight control control systems & hydraulic systems
From the post a few up, the crew being unable to dump/transfer fuel thanks to collateral damage is troubling. It may be beyond the capacity of aerospace plumbing to modify/revise/improve the fuel transfer or dump interlocks and protection to allow for a way around that. And they were unable to shut down an engine from the cockpit. Also discomforting.
Maybe one could complain about the "design" of the fuel management system as a whole, in that there wasn't a way for the crew to work around their failures and be able to offload some of that extra weight before landing.
Having read the preliminary ATSB Report, I wonder if I'm the only one still puzzled by the root cause of the engine failure. They say on page 16 that a "recent key finding" was the fatigue crack associated with a "mis-aligned area of counter-boring" in the stub pipe. Yet they don't seem to conclude that this manufacturing error was indeed the cause?
And if it was, then what about the earlier ADs issued; do we now assume that at that stage they were issued as catch-alls, more in hope than expectation?
And if it was, then what about the earlier ADs issued; do we now assume that at that stage they were issued as catch-alls, more in hope than expectation?
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"mis-aligned area of counter-boring"
Am I the only one that finds this manufacturing error astonishing? At the end of my career I spent many years in an aerospace manufacturing company. Every single component that was manufactured in our shop had an extensive QA inspection and test before shipping. This involved, among other things, detailed visual inspection, NDT crack detection (dye penetrant or magnetic particle) and computer controlled coordinate measurement of all of the component's key dimensions. There is absolutely no excuse for an error of this magnitude. Whoever made that oil pipe has had a massive QA failure in their factory.