Posts about: "Dual Engine Failure" [Posts: 231 Pages: 12]

The chances of hitting a flock of migratory birds on take off near a tidal estuary are considerably less than a billion to one.

An aircraft using derated thrust will use most of the runway to reach V1. It's not far too late. The initial climb looks normal.

If the flaps weren't set then the aircraft would have accelerated on the runway faster, not slower. But I don't think the flaps were set wrong, or retracted early. The flaps appear extended in the video and the post crash photo. Why do you think a bird strike after V1 is unlikely? If you fly into a flock of birds a double engine failure is no less likely then a single failure. My initial thought watching the first video this lunchtime was power loss in both engines, probably bird strikes. I still think that.

If both engines failed then all four of those things would happen very soon afterwards.

Both videos evidence a normal rotation and climb followed swiftly by an abrupt cessation of the climb. No sign of yaw. But an apparent catastrophic loss of thrust. To me this points to dual engine failure. Statistically the most likely cause would be bird strike. The flap/gear configurations are probably not causative.

The theories concerning inadvertent flap retraction are not consistent with the apparent transcript from the mayday call made or rat deployment. In the first video that circulated, the engines can\x92t really be heard (certainly not producing any significant amount of thrust). If the aircraft was climbing out misconfigured, those engines would be screaming. Instead, all you can hear is the rat.

Similarly - a bird strike, knocking out two engines simultaneously is a noisy/messy event and I would expect to see evidence of this occurring in both videos, and in the area at the point of ingestion. The engines don\x92t just roll back with a bird strike - they surge, smoke, bang and splutter. It would be very apparent.

At this time, I think everything is pointing towards both engines simultaneously having their fuel feeds interrupted between V1 and Vr. CVR/FDR will be interesting.

I hate to say it but it looks to me like a dual engine failure or both engine master switches set to off after take-off.

Both situations are harrowing 😣

RIP and thoughts to all the families

The issue I have with the \x91mis-selected flaps up\x92 theory is that if PM had accidentally retracted flaps, I\x92d expect the PF to lower the nose, apply max thrust to try and accelerate by flying level or in a minimal descent. In this accident, the nose never seems to get lowered to decrease the AoA, in fact pitch increases just before it seems to stall. I\x92d also expect similar for an overweight takeoff, thrust or loadsheet error.

The fact none of the above happened, coupled with the lack of landing gear coming up, makes me think they didn\x92t have thrust to play with.

Your profile says this.
How familiar are you with the Boeing 787 flight deck and its controls?

A link to the report Zoot0 referred to:
https://ad.easa.europa.eu/blob/AIR-2..._AIR-22-09R1_1

Excerpt in the spoiler


{there is more, this is just a taste, see the whole report for details}.

Would any of our 787 qualified pilots care to comment on this as it relates, or doesn't relate, to the aircraft's brief flight shown on the CCTV video?

I strongly agree with you. Fuel Cross feed valve is an example.

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.

Intriguing: agree it doesn't look like an inadvertent flap-less take-off, but having watched the video several times, I can’t see any sign of a pitch-down input (ie, less pitch up) that would surely be evident following a dual engine failure. Even if the loss of almost full power from underslung engines didn't naturally cause a change of pitch (FBW), surely the first instinctive control input following such a large loss of thrust would be to lower the nose a little.

Conversely, the rapid sinking feeling induced by the inadvertent Flap retraction at the Gear-up point could confuse the senses and be interpreted as a loss of thrust?

Tragic whatever the cause; I’m sure we'll have the answer fairly soon.

I\x92ll reply to my own post in light of the RAT deployment. If true then this opens up to a lot more. And simply guessing with grainy video a fools game. All I saw was gear down to high Into the climb. This should not happen under any circumstance . Dual engine failure would explain the loss of lift obviously. Early flap retraction also. One would hope it\x92s not a simple as that: cheers

Not 757 - it was a 767. Second time it happened in about 12 months.

Determined to be an ergonomics problem with the switch layout in the flightdeck.

Early 767s (JT9D and CF6-80A) had a supervisory "EEC" (Electronic Engine Control - Boeing still uses "EEC" to identify what most people call the FADEC on modern engines). The procedure if an EEC 'failed' was to switch both EECs off (to prevent excessive throttle stagger - unlike FADEC, the engine could operate just fine with a supervisory EEC failed).

Problem was that the EEC ON/OFF switch was located on the aisle stand - right above the fuel cutoff switches. Turned out 'muscle memory' was when the pilot reached down there, it was usually to turn the fuel ON or OFF - which is what they did. Fortunately realizing what he'd done wrong, the pilot quickly restored the switches to RUN and both engines recovered. And yes, they continued on to their destination (RAT was still deployed since there is no way to retract it in-flight).

Previous event was with JT9D engines (United IIRC). In that case, only one engine recovered (second engine went into an unrecoverable stall), they simply came back around and did a single engine landing.

Realizing the ergonomic issue, the EECs were relocated to the pilot's overhead (retrofit by AD).

To the best of my knowledge, there hasn't been a repeat of an inadvertent dual engine shutdown since the EEC switches were relocated. It's also very difficult to 'accidentally' move the switches as there is a locking detent - the switch must be pulled out slightly before it can be moved to CUTOFF.

Would not be the first time that an accident has uncovered unintended consequences of a particular fallback configuration that was never able to be checked by either/any of Airbus, McDD or Boeing developmental test-pilots. Thinking of the automatic thrust augment/restoration on the MD81 (regn OY-KHO) that crashed 27Dec91 near Gottrora in Sweden (double engine failure). Design Boffins failed to realize that ice-sheet ingestion (sliding off the wings to be ingested by both rear-mount engines) would not benefit at all from each engine hiccup causing a continual uprating of the other (and vice-versa). To be found/uncovered in a simulator you would have to be testing various pilot inadvertencies (rather than rote expected actions). Then again, don't always believe the outcomes to be seen in a simulator. They don't necessarily faithfully emulate what would happen systems-wise in an aircraft... particularly when it comes to complex materiel failure modes or illogical sequiturs (e.g. MCAS)

So, if such an untestable circumstance were to happen to a competent crew and they were to inadvertently shut-down the wrong engine (and then/were in "clean-up mode":

a. The residual hyds would break the downlocks - but not retract the gear (and it would appear to be still selected down)
b. The alternate flaps might start to retract (gear downlocks not being now "made") once selected, but the slats remain out.
c. the RAT would deploy

The point at which all thrust ceases (and the climb vector flattens/reverses) is easily seen
in the video shot from the 6:30 clock position from about a km away. It's readily apparent.

An engine failure just off the runway after V1 in a fully loaded 787-8 in high ambient temperatures would assuredly have a crew thinking about a "toute suite" shutdown of a misbehaving donk. That's human nature. When the PERF is quite sluggish you will be thinking that a quick clean-up of the situation is certainly called for. That's just human nature unfortunately, particularly when you are under the time compression of dire circumstance (and the airframe is performing like a lame dog, just due to the environmentals and the early failure). I think that what the pilot reportedly said to ATC in his Mayday bears that out as being his instant mindset (quite clearly). Been in that "fools rush in" circ myself. You just have to "sit on your hands" and fly the beast.
But then again, if the RAT was NOT found deployed, then it's a case of the right seat mistakenly sucking in the flaps and slats... and that will do it... whatever the power/TOGA might be.
https://tinyurl.com/4zzkeeud
Rotation +33s
Mayday call +44s, circa 300 ft altitude (ADS-B)
Peak altitude +49s, 625 ft (Flightradar24)
Impact +58s, crash site 1.6 km from runway

Sorry but you are wrong. The RAT was basic on the 767 - every single 767 built has one. The Gimli glider deployed the RAT (1982), and the Delta dual engine shutdown out of LAX deployed the RAT.

There's no evidence of bird strike on any of the videos. Fuel starvation/contamination is highly unlikely to impact both engines simultaniously. One other possibility is a catastrophic software failure, as Boeing had with the 737 Max.

If it is true that the RAT deployed during the flight, possibly from early on in the 30s of airborne time, and multiple independent pieces of evidence suggest that this is the case, then that narrows down things considerably. Double engine failure, massive electrical issues or fuel control switches / fire switches on both engines are all I can think of that could cause this. Gear/flaps etc. are a red herring. During the period after the power loss and before the RAT came online (up to 8s AFAIK ), almost everything would have been load shed as battery power only.

Can the RAT be deployed manually\x85

The only thing that is clear from the footage is that the gear remains down. Which has led to the theory that the loss of lift is a result of the flaps being raised by mistake.

However a deployed RAT would be compelling evidence of dual engine failure or shutdown.

Another explanation for the gear remaining down could be startle/distraction caused by engines rolling back at around rotate or liftoff.

As has already been pointed out, these deployments were deliberate for test purposes and the approaches were done into airfields used by manufacturers for trials. Unless the Air India crew thought it would be fun to see what happened if they deployed the RAT shortly after takeoff, we are looking at something triggered by one or more of:

System-wide electrical issues
Double engine failure
Selection of fuel switch and/or fire switch on both engines

Any speculation about gear, flap, runway, etc. is redundant if the RAT did auto-deploy as it points to a very serious technical issue with the airframe rather than what was done with thrust levers or what the pilots had for breakfast.

I haven\x92t seen what the 787 cockpit looks like on battery power only but on the 777 it gets pretty dark with only the essential P1 instruments and VHF1 available until the RAT comes online, which is a measurable amount of time after deployment is triggered.

Confirmed, as so we can all move on, reference attached. And for the guy that flew 767\x92s for 40 years and didn\x92t know anything about it 😂