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Qantas A380 was seriously lucky

Dousing the No 1 engine to stop it at Changi

Dousing the No 1 engine to stop it at Changi

The seriousness of the Qantas A380 incident at Singapore and over Batam Island earlier today is made apparent by photos of the damage placed on the public domain by some of the passengers.

An image, shared by passenger 'ulfw', locates the wing punctures

An image, shared by passenger 'ulfw', locates the wing punctures

They show that what has been identified as a part of a turbine blade passed through the wing above the No 2 engine (shown above) and lodged a short distance behind the leading edge but in front of a major fuel tank, where there is indirect evidence that it severed some of the wiring that relays instructions to the outermost No 1 engine.

That evidence is seen in images of the fire tenders being used to douse the No 1 engine (top of page) after the giant jet came to a standstill, as it could not otherwise be shut down while fuel remained accessible to it.

The photos also show that at least part of the hydraulic functions of the A380 had been rendered inoperative, with visual clues that the nose wheel may have relied on a gravity drop rather than hydraulics to power it into the locked down position, and that the slats on the wing had not been deployed before landing resulting in a faster and longer landing roll.

A closer look at secondary wing 'punctures'

A closer look at secondary wing 'punctures'

The sources spoken to differed on whether small fragments of the disintegrated No 2 engine that punctured the wing further aft (detail above), in the area containing fuel tanks, were really responsible for reports of fuel leaking from the back of the wing as the jet finally landed back at Changi almost two hours after the incident began with that engine failing explosively about six minutes after takeoff for Sydney.

The cautious assessments given to Plane Talking refer to details that can only be resolved by the accident investigation despite the clues in the passenger and news report images.

But the problems that beset the pilots when the No 2 engine blew help explain two things, the length of time taken to return to Singapore Airport, and the conviction shown by Alan Joyce when he grounded the Qantas A380 fleet.

The pilots clearly took their time dumping and consuming fuel while they assessed the situation and discussed it with Qantas operations and most likely Airbus and Rolls-Royce, dealing as best they could with control issues affecting the No 1 engine, and working with the airport authorities on the plan for shutting it down after touchdown.

There would have been careful consideration of everything else that could have gone wrong in an abnormal landing. Joyce and a response team would learned very quickly how potentially catastrophic the engine failure had been, and arrangements to rebook literally thousands of Qantas A380 travellers for an indefinite period would have begun well before he announced the grounding of the giant jets.

One of certification standards for passenger jet engines is the ‘containment’ of component failures. This was a severe uncontained failure by the Rolls-Royce engine. The cause must be found and corrected, whether it is a flaw in a component, an error in assembly or overhaul, or a hitherto undetected design failing.

Whatever it was, it has to be found and fixed. Joyce had no choice in the actions he took.

The rear section of Engine No 2. REUTERS

The rear section of Engine No 2. REUTERS

The other users of the Rolls-Royce Trent 900 on A380s are Singapore Airlines and Lufthansa. The German flag carrier has only recently started its A380 operations, while Singapore Airlines has 11 A380s in service, compared to six with Qantas, and has been flying the type longer.

However the history of engine issues in airliners in general is not linear. Long established designs have sometimes exhibited faults in recent builds because of production or materials imperfections. Or maintenance issues. There is no reason to assume that anything that happens in service to Qantas will happen to another airline, or vice versa.

Qantas, the ATSB, its Singaporean and Indonesian counterparts, and Rolls-Royce, all have a serious puzzle to solve.

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  • 1
    Mark Parker
    Posted November 4, 2010 at 11:02 pm | Permalink

    Ben,
    Clearly as time passes we’re starting to understand the gravity of this incident.

    My questions around this include:

    (a) Looking at the last photo – that looks like a seriously destroyed RR Trent – will they be able to learn anything from it?

    (b) What of the pilots? I had to endure an hour of Sky News hysteria (in the Sydney Qantas Club of all places) yet no mention of their actions – what they had to confront, how they dealt with this situation (would they have done an exercise like this in the sims?)

    (c) What are your thoughts re how Qantas handled the emerging “crisis” – you touched on this earlier in that Qantas took the unprecedented step of responding to media rumors/hype – what are your thoughts on how they handled the day?

  • 2
    Ben Sandilands
    Posted November 4, 2010 at 11:51 pm | Permalink

    Mark,

    I think Qantas handled this one very well. Joyce was decisive, and clearly had the benefit of a detailed and sobering assessment of the incident. Picking up on the interviews with passengers, and the realities of an unprecedented configuration in a nearly full A380, the pilots excelled. And let’s hope we learn everything from that engine. This was a real lesson in how dangerous uncontained failures can be. I can say there are A380 ‘sources’ in other carriers who are full of admiration for Qantas over this incident.

  • 3
    Angra
    Posted November 5, 2010 at 9:25 am | Permalink

    The Guardian reports that airlines were warned about the Trent 900′s in August.

    “Qantas refused to discuss an airworthiness directive issued by the European Aviation Safety Agency in August which warned that scrutiny of stripped Trent 900s had found that unusual wear on splines used to secure the turbines could lead to engine failure coupled with “oil migration and oil fire”.

  • 4
    Ben Sandilands
    Posted November 5, 2010 at 10:06 am | Permalink

    The Guardian on this occasion is not quite right. The original warning was issued by the European aviation regulator in January and incorporated in US regulations by the FAA in August as a matter of form, since there are no US Trent 900 operators. The warning is however very interesting. Opinions of those I’ve spoken to are divided as to whether or not this will prove a factor in this incident, for example, if it proves to be an entirely different fault, but it certainly put Qantas, Singapore Airlines and Lufthansa, who all fly this type of engine on their A380s on notice.

  • 5
    kate
    Posted November 5, 2010 at 12:32 pm | Permalink

    I flew Qantas to LAX in June. Was supposed to be on the A380 but replaced by 747 at the last minue. The flight attendant said it was because the A380 was grounded in Singapore due to problems with the fuel tank. The way he explained it was that fuel is supposed to be drawn evenly from both tanks, but that this plane had been drawing fuel from one side first, and then the other, leaving the plan unbalanced. No-one could work out why, and so the plane couldn’t fly.

    Does any of this make sense? I know absolutely nothing about planes (I had an engineer boyfriend years ago who tried to explain uplift etc but I still don’t really get it) so I suspect I may have been hoaxed.

  • 6
    Posted November 5, 2010 at 12:38 pm | Permalink

    Ben – d’you think there’s any connection to the QF74 incident? Both the old RB211-GH/T in that case and the Trent 900 in this case are supposed to receive additional inspections at every B-check due to known turbine wear issues (HP turbine for the RB211, LP turbine for the Trent following the EASA warning), which should make this kind of catastrophic failure impossible.

    For QF’s maintenance staff, to lose one engine is a misfortune; to lose two looks like carelessness…

  • 7
    Neil Doody
    Posted November 5, 2010 at 1:59 pm | Permalink

    Maintenance issue or no, it seems that one of the most hazardous times for any jet engine in flight is the point at which they throttle back after the initial climb from take-off. That seems to have been the point where this incident occurred, and I’ve noted numerous others in the past.

    I clearly recall being caught in one of these on Cathay in the mid-90′s out of Hong Kong. On that occasion the pilots couldn’t put out the fire so we landed straight away, no time for fuel dumping. Quite spectacular, a bit like the F111 dump-and-burn but rarely seen on a passenger jet.

    It seems that design flaw is still present on modern-day engines.

  • 8
    Ben Sandilands
    Posted November 5, 2010 at 2:19 pm | Permalink

    Kate,

    The issue was contamination caused by a bug that grows in aviation fuel. It caused all sorts of fuel management issues for Qantas, but I don’t recall lopsided flying was one of them. This problem has sprung up at irregular intervals for a long time. I recall Qantas being one of the Lockheed Electra operators that it picked on in the late 50s or early 60s.

    Johnb78,

    I was critical of argument by Qantas that the RB 211s didn’t need additional examination after the SFO incident, in which they argued, factually correctly, that they had carried out the work already when the incident happened out of the ‘blue’, or in fact, over it. The ATSB is still investigating that incident. If Joyce had been consistent Qantas would have pulled each 744 with RB-211s for a special look see before dispatching them across the far southern Indian ocean or trans Pacific or to South America. It’s a long way to a emergency strip on those routes, as it is for an A380 between here and LAX. This time the right call was made. I hope it indicates a policy change in terms of pre-emptive inspections.

  • 9
    Mman
    Posted November 5, 2010 at 2:38 pm | Permalink

    Just a thank you for the information about the shutdown problems on the number 1 engine.
    I couldn’t figure out why the emergency crews were spraying it down.

    Is there any more info out there about this part of the problem?

  • 10
    Ben Sandilands
    Posted November 5, 2010 at 3:17 pm | Permalink

    Mman,

    There is a later post touching on this here:

    http://blogs.crikey.com.au/planetalking/2010/11/05/qantas-raises-a380-design-flaw-possibility/

    As ‘Casual Observer’ notes in the comments, airliner designs have little wriggle room on this, although one might reasonably anticipate that a wireless backup command facility might be included in designs at some future time, when the risks of ‘hacking’ with intent or by accident are addressed.

  • 11
    Bill Parker
    Posted November 5, 2010 at 7:35 pm | Permalink

    When I was a student in bacteriology in the late 60s, one of our lecturers was consulting to the Concorde builders (Concorde actually changed its direction by pumping fuel side to side and front to back) The pump seals were being eaten by bacteria. (probably fungi in fact – Cladosporium) The fellow was proud of the fact the he had been able to solve the problem. So I am surprised to hear this is still relevant.

  • 12
    Dave
    Posted November 5, 2010 at 9:50 pm | Permalink

    “One of certification standards for passenger jet engines is the ‘containment’ of component failures. This was a severe uncontained failure by the Rolls-Royce engine. The cause must be found and corrected, whether it is a flaw in a component, an error in assembly or overhaul, or a hitherto undetected design failing.”

    There are containment standards, generally relating to fan or turbine blade release – however if a disk bursts there is too much energy in the large sections of disk to be contained, so they invariably exit the side of the engine. The certification standards for disks are to avoid failure in the first place: by design, imposing a fixed fatigue life and a thorough inspection/maintenance regime.

    It looks to me like a big chunk of the burst turbine disk went up through the wing, thankfully missing the fuselage – that is what makes this potentially so serious – imagine the consequences if a large chunk of metal had passed through the passenger cabin.

  • 13
    Dave
    Posted November 5, 2010 at 9:59 pm | Permalink

    Bill Parker,
    “Concorde actually changed its direction by pumping fuel side to side and front to back”

    Sort of – Concorde could pump fuel around it’s wing tanks to trim the aircraft, i.e to maintain direction, not to change it – e.g if the aircraft was tending to climb, fuel could be pumped forward to bring the nose back to level flight. This was preferable to deflecting a control surface which would cause an increase in drag (and fuel consumption).

  • 14
    DA
    Posted November 9, 2010 at 3:53 am | Permalink

    Rolls Royce have the major problem. No matter what causes a trubine explosion it MUST be contained by the armoured containment belt this is A FAR requirement which clearly did not properly function in this case. Therefore grounding of the fleet may become a safety necessity until a modified engine containment belt is approved and fitted.
    From an EX Areospace engineer.

  • 15
    AKRefugee
    Posted November 9, 2010 at 8:22 am | Permalink

    RR knew they had a problem with this engine. There are 2 AD’s out on the Trent 900. With the pics of the turbine blades embedded in the wing I would guess the HPT disk
    had an “shortfall in component life” and a “premature cracking” as outlined in AD 2009-18-13 Rolls-Royce plc effective October 14, 2009, a different one from the one regarding the spines. Guess the AD didn’t go far enough. Another case of a manufacturer rushing product to market, RR felt this was a make or break engine for them because they were trying to convince Boeing to go with a derivative of the Trent line on the 787’s.

  • 16
    Dave
    Posted November 10, 2010 at 9:21 pm | Permalink

    @ DA
    “No matter what causes a trubine explosion it MUST be contained by the armoured containment belt this is A FAR requirement which clearly did not properly function in this case.”

    Sorry to contradict, but the armoured containment is only on the fan case to contain a released fan blade – there is no armouring on the turbine casing to contain an explosive disk burst. A turbine blade release would normally be contained, but a disk cannot be, so the design criteria is that it should never fail !

  • 17
    DA
    Posted November 12, 2010 at 7:02 am | Permalink

    Rely to Dave. “Sorry to contradict, but the armoured containment is only on the fan case to contain a released fan blade – there is no armouring on the turbine casing to contain an explosive disk burst. A turbine blade release would normally be contained, but a disk cannot be, so the design criteria is that it should never fail !”

    Yes you are correct Dave. Being out of the industry for a while. so i have done a bit of catching up with a few collegues and the requirment is that the compressor is tested to 2 life times and then that is then assume never to fail. I wonder if they ever finished that test? Considering how long these engines have been in operation. I am also hearing from my collegues that a disk did actually fail on this engine and thus the explosion. Clearly the certification process failed. Both Rolls Royce and the FAA and the UK certification authorities need 1) to investigate fault. 2) revisit the change to the requirement to never fail when double life time tested.

    Side note:- This aircaft was very very lucky if a turbine part had punctured the fuel tank I feel the ending would have been very ugly.

  • 18
    DA
    Posted November 13, 2010 at 3:05 am | Permalink

    Additional Very Disturbing Information.

    Airworthiness Directive (AD) 2010-0008 dated 15 January 2010 issued by EASA(European Aviation Safety Agency) regarding the RB211 Trent 900 series engines A380 engine. shows the turibine poblem was known at this time and also the seriousness of the problem and the reason of this AD.
    Quote:-
    ” Rearward movement of the IP turbine would enable contact with static
    turbine components and would result in loss of engine performance with
    potential for in-flight shut down, oil migration and oil fire below the LP
    turbine discs prior to sufficient indication resulting in loss of LP turbine disc
    integrity. Some of these conditions present a potential unsafe condition to
    the aeroplane.”

    So rolls royce had alerted the authorities to this potentialy catastrophic turbine explosion resulting in this AD and the inspection process requirement.

    Related information going from bad to worse:-

    A Quantas 747 -RB211 (Rolls Royce) lost a complete IPT disc (all blades gone) in August. It didn’t get press because it was not an A380
    A Trent 1000 (B787) had a major uncontained failure on the test bench in Derby a few weeks ago.

    Looks to me the Avaiation industry is pretty Screwed up since I left too many wrong decisions by the FAA and EASA with regards to will not fail idea as a means to certify.

    Clearly recent events has shown how wrong and potentially fatal that idea can be.

    Happy Flying.

    DA

  • 19
    todd
    Posted November 20, 2010 at 4:48 am | Permalink

    Katie yes the uneven fuel burn happens it can happen in any plane. theres are several reason this can happen weak fuel pumps bad cross feed valves qf did the right thing and pulled it out of service

  • 20
    todd
    Posted November 20, 2010 at 5:19 am | Permalink

    far 33-19 states the design of the compressor and turbine rotor cases must provide for the containment of damage from rotor blade failure

4 Trackbacks

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