Posts about: "Fuel Contamination" [Posts: 64 Pages: 4]

Dual engine failure due to fuel contamination?

or birds?

True. We won\x92t know until the CVR and Flight Data recordings have been analysed. I think these will give a clear indication of what happened. The airport has reopened so I assume there\x92s no fuel contamination risk.

Fuel contamination?

That was my first guess

A dreamliner can cope with multiple failure scenarios on take off but fuel contamination isnt one of them

options
Serious pilot error (retracting flaps etc)
fuel issue
birdstrike
some new latent technical common issue in engine control systems

Medical episode on flight deck resulting in sedrious pilot error?

Like the dual engine failures that occurred on every aircraft which took off before it, using the same fuel supply?

😩

Symmetric is the key word.

The chances of both engines having simultaneous flame outs due to fuel contamination is almost not possible...too many variables to have them fail at the same time.

What we are seeing is a fairly stable flight path....in that the wings remain level throughout and a point in the flight where the vertical profile changes from a normal take off flight path into the high nose attitude descending one...albeit without any significant or abrupt maneuver.

Strange.

Heathrow 777?

That was my first thought. You don\x92t get a double engine failure for nothing else but that and maybe birds, but birds would have caused some trailing smoke or at least some visible signs on cctv at some point throughout the ingestion period.

No\x85
Certain jet fuel types may not be authorized for use by the manufacturer but the engines would still run.
Jet engines can run on (almost) anything.
its not like Jet A into a piston engine.

https://assets.publishing.service.go...211_G-POWN.pdf

One example of fuel contamination causing a significant loss of thrust on both engines at low altitude.

But it seems extremely unlikely for contaminated fuel to impact both engines at exactly the same time, with no asymmetry and no surges or smoke.

What can cause a sudden catastrophic loss of thrust on both engines at exactly the same time?

Birds (but no apparent surges)

Inadvertent movement of the fuel cut off switches (which would be an incredible error but I suppose it could conceivably be muscle memory having done so recently after the last leg\x85weirder things have happened. Remember the 767 events of the late 80s)

Intentional shutdown of the engines (pilot suicide has happened before)

Some catastrophic electrical/FADEC/engine interface failure (which I highly doubt is feasible in a modern 1309 aircraft)

I can\x92t think of any others\x85

From the airport CCTV video it looks to me like a normal takeoff and start of climb, until suddenly there's a loss of climb performance with no obvious upset at that point. From the picture of the wing post crash it looks like the flaps were still deployed (N.B. based on pre-accident photos that's the right wing so closest to the camera is aileron and flaps are further away, damage had me confused first time), so I'm going with loss of thrust rather than flap retraction.

From the videos from bystanders it looks like RAT deployment (both sound and zoomed in pictures) rather than thrust lever retard, and that would also explain failure to retract gear - if you are dealing with both engines out at that altitude then gear isn't your first thought. From the airport CCTV video I don't see anything that looks like bird strikes at that point in the climb i.e. no obvious flocks of birds, no smoke out of the engines, no slewing one way as one engine fails and then the other is cut by accident - plus you wouldn't cut the engine at that point, you'd climb on one engine and then sort it out.

Even fuel contamination or water build up in both tanks is likely to result in one engine failing a few seconds before the other. So I can't come up with anything other than both fuel cutoff switches that would result in loss of thrust and RAT deployment. Looking at a picture of the cutoff switches https://www.nycaviation.com/2013/08/...is-fired/30179 I don't see how they get hit by accident.

I'm confused, hope we get an FDR / CVR readout soon.

This aircraft has got airborne well within the requirements of FAR 25 under which it was certified. It has over 1250m ahead of it passing around 35' based on the video from behind, so the FMC data was not incorrect, the thrust up until after TO was not incorrect, and the CG is not out of range, the time to rotate is within expected range, and the attitude at liftoff is not excessive, the plane is not heavier than expected. This is not Emirates, Tiger or SQ, it may have a resemblance to AFR out of Nigeria, or ANZ out of Raro, or UAL out of Hilo. Unlikely but there are similarities.

A low altitude in the MCP can become pretty interesting, as will a TAT probe failure to the ATR thrust limit. Both cases will have the thrust levers moving back rapidly. There is no obvious failure of the engines at this point save the question that the RAT may be deployed. A transient electrical fault tripping the logic for the RAT is hard to imagine, but that would possibly end up with an ATR fault and power coming back to idle. Fuel contamination is not impossible, but it is improbable, the engines would have been on their TO configuration from the engine start, and the taxi and turnaround takes enough time to flush the fuel lines, being longer than the selected tank sampling time that sits behind the SOPs. Boeing aircraft are easier for the crew to detect anomalous thrust commands compared to the Airbus, however, if the RAT is out... then more was happening.

The flaps are in the correct position, we are looking at a time critical failure for the crew, they appear to have around 10 seconds between onset and impact, and they have rotated the aircraft in the later stages, as any reasonable pilot would do, and that certainly does not indicate a crew initiated problem on the available information. Unlawful interference is unlikely, given the RT calls that have been made.

The IDGA AAIB is not known for rapid response, this event is of international importance, it appears that it is being treated as such by the authorities involved. The EAFRs on the 787 will tell all soon, and we need that information, this is a globally important aircraft type.



The pilot is being quoted as saying to ATC:

"Mayday...no thrust, losing power, unable to lift"

I don't think a pilot with over 8000 hours experience would mistakenly diagnose that. Also corroborates with the RAT being deployed. Question is how do both engines lose thrust. Bird strike is the obvious one. Fuel contamination seems unlikely.

I see a post above showing how its possible an electrical failure can result in power loss. Passengers on the flight before this said there were issues in the cabin; lights, displays and air con was not working. Again, seems v unlikely to be related.

That post is simply wrong - if all aircraft electrical power is lost, the engines will keep running just fine (suction feed is demonstrated to be sufficient in the entire takeoff envelope, so even losing boost pumps wouldn't cut engine power).

Re fuel contamination. Shouldn’t the engines be feeding from separate tanks at that point? What are the odds of simultaneous Engine Failure? (Basing that on there is little yaw or wing drop to the live)

It’s years since I looked at it. I thought it was in the FARs explicitly but I can only find CFR 25.1309 states the safety analysis for equipment systems and installations that would be likely encompass this.

Such a terrible shame, condolences to all. It looks inexplicable from the CCTV.

Seems time for a visual evidence review.

There seems to be a RAT theory based on a hyper zoomed artifact and someone showing a RAT deployed on a different airframe. Not convinced about that, you might get a similar artifact from a belly antenna. The noise? CCTV doesn\x92t have noise and the other pictures I saw were from a car in traffic.

Others are are saying it climbed to 500\x92, not sure about that, the highest I have seen visually is less than 300\x92, QNH vs. QFE I suspect.

Flaps vs. Gear definitely a possibility and the AoA was increasing particularly after the descent started.

Double EF (If RAT deployment not a red herring) Fuel contamination? Would have to be deliberate as no other aircraft affected, unlikely. Maintenance or crew error, possible unlikely. Bird strike, no evidence.

MTOW error possible but it seemed to take off fine so no reason for the return to the ground.

What about the bang the survivor heard? I suspect you can treat the evidence of anyone involved in an air crash with a pinch of salt. Order of events are often out of sequence even when talking to trained observers in less stressful situations

MCP mis-setting to 100\x92. Engage AP early, often seen, thrust immediately commands to idle by ATHR, starts to sink, extreme startle and forget gear because it appears like a double EF.

I know where my money is but only time will tell, if they get the Black Boxes in good condition, the factual statement should clear it up quickly.

The aircraft is refuelled from the same single point source.
If the fuel from the bowser/ground tank was contaminated it would affect both engines.
However, this would also have affected other aircraft at the airport. It could of course been refuelled with the wrong fuel, but that\x92s pretty much unheard of, and big engines like this can pretty much run on anything that will burn.

Your MCP theory sounds feasible but doesn\x92t stand up to Boeing VNAV engagement logic (assuming it\x92s typical Boeing) which would mean at 400\x92 the aircraft would still try to maintain V2. It just might pitch the wrong way. Interestingly, the AT system has caused more accidents on the Boeing than the Bus. Much to everyone\x92s surprise considering the TL\x92s don\x92t move on the Bus..