Posts about: "RAT (Deployment)" [Posts: 361 Pages: 19]

That very much sounds like the RAT is deployed as the aircraft goes by the camera.

The noise certainly matches " target="_blank"> The noise certainly matches

Hard to say and the noise could be a fake. It's hard to tell what's real these days.

Comparing the sound at the beginning of this video:
https://www.reddit.com/r/ahmedabad/s/Oz5hQzDiu5

With the sound of the 787 at the 1:14 mark


It sounds like it had the RAT deployed?

That sure sounds like a RAT is deployed on that video, unless it\x92s a vehicle passing by.

I think I can somewhat see it deployed during the pitch up.

How horrible. From what has surfaced so far, it does appear that the aircraft became airborne and got to a reasonable height and groundspeed, within parameters for a normal takeoff. The video with RAT-like audio and the snapshot from another video showing hints of RAT deployment seem to be the biggest clues so far: flaps and gear are a minor issue compared with a serious power loss, although loss of electrical power would trigger the RAT if it uses the same logic on the 787 as earlier Boeings.

That you can hear the RAT on the video over what should be engines at takeoff thrust at that point adds credence to the theory, as does reports of a MAYDAY.

For an aircraft that will likely have TOGA pressed and be at a high power setting (plus the RAT deployed) it sounds awfully quiet.
Perhaps the gear was down because they knew they were going to force land due to lack of thrust.
(Only a 738 driver), but the electric pumps to drive the hydraulics is much slower than the engine driven pumps and so flap selection / re-selection could be not as expected.

RIP to all involved.

787 gear and flaps/slats are both on the centre system, powered by 2x big electric pumps and no EDPs, so retraction should be minimally impacted by engine failure assuming electric power was still available and reconfiguration worked. Note the 787 has two generators per engine so generator failure is also unlikely to contribute, unless both engines failed taking out all four generators (and presumably no APU running).

From that thread, I believe it was discussed that on most/all other large transports, deploying the RAT re-powers the CVR/FDR. The 737 didn't have that happen because no RAT. You may still get a few second gap while the RAT deploys.

The 787 has 2x Enhanced Airborne Flight Recorders (EAFR), which each record both cockpit voice and flight data. I expect they are also fitted with the dedicated batteries that the Jeju was a year or two too early to require. Per the NTSB , the forward recorder has a 10-minute backup battery.

Hopefully flight data is not going to be an issue for this investigation.

The suggestion is that the buzzsaw/propeller sound is the RAT; it does sound a bit like an interference pattern, but you don't get the engine roar with it.

It's also maybe visible in a few stills (e.g. post 64).

The audio is not great and kind of whiny. Even at the end when the crash happens, it does not sound robust.

Likely: this is not the RAT sound; it is just poor audio pickup.

Just to confirm.
The 787 is an aircraft which likes to, performance wise, use all of the available runway for takeoff. Sometimes you can be sat in the 787 and as you are rolling down the runway, you start wondering if Rotate has been called or not. It loves taking up all of the runway.

Nevertheless, there are some interesting speculations over on X. One guy even claimed the Captain was in the lavatory during the accident...

Many people have noted what appears to be the RAT deployed in the video footage suggesting dual engine failure. Possible wrong engine shutdown? But who diagnoses and actions an engine failure and shutdown below 400ft?

It looks like an action slip to me as the timing looks right ie \x93positive rate \x93 \x93gear up\x94 (someone raises the flaps instead of the gear) PF is looking through the HUD so just sees someone move their hand rather than the hand moving the correct lever

It\x92s then taking off heavy weight with 35c and the flaps have been raised and the gear is still down.

As nobody realised the flaps had been raised instead of the gear when it happened they automatically think it\x92s some other issue as the aircraft loses lift and the amber band rapidly rises and the aircraft runs out of lift.

could be something else like fuel or 2 engine failure but seems possible it\x92s an action slip also.

I didn\x92t see the RAT deployed but saw the gear down still and an aircraft fall out of the sky with what sounded like engines running still.

aviationweek.com/aerospace/aircraft-propulsion/faa-boeing-787s-need-be-powered-every-120-days

aviation.stackexchange.com/questions/14494/in-what-circumstances-could-a-787-stay-powered-on-continuously-for-248-days

Loud bang heard by pax 11A suggests otherwise. (ie EFATO) but still\x85

Could It have been a compressor stall / flow reversal at the point of EEC shutdown? Loss of thrust on both engines?

The odds are slim but would the RAT deploy in such a scenario?

(or has the RAT deployment observation been debunked?)

But why is the RAT extended? Any 787 drivers able to confirm under what conditions the RAT automatically deploys?

Who said it is deployed? I don't see it deployed. How would it even have time to deploy, it crashed within 30 seconds!

This is a higher quality video posted earlier. That is not two engines at TOGA and sounds incredibly like a RAT. I think most commenting about not hearing a RAT are watching the more widely shared low quality vid with very poor sound.

I have heard 777s and 787s pass overhead with the RAT deployed many hundreds of times. The sound in that video is 100% a deployed RAT.

What is the precise trigger for the RAT to deploy automatically on the 787? Full failure of both engines?

You are saying the RAT is deployed but we can rule out engine failure?

I thought this was meant to the *professional* pilot\x92s forum

Gear unable to be retracted and flaps retracted due to no hydraulic pressure? It would certainly explain the RAT being deployed and the loss of lift.

Of course the RAT will deploy if all three hydraulic systems have low pressure even with both engines running. This is the case on the 77/78.

Please all... let's get more facts and data before unwarranted speculation about cause or culpability.

That's especially pertinent about questionable aspects like flap extensions used for takeoff, temperature effects, limited runway distance, and other likely irrelevant circumstances.

The "bang", Mayday call, potential RAT deployment, and high alpha touchdown may prove significant, ....if and only if they are later verified by accident investigation.

It is most inappropriate to yet for any professional aviators be inferring any flight crew, airline, or OEM connections whatsoever. Only sympathy and aid for the crew, passengers, families, airline, and those impacted by this tragic crash, and support to the accident investigators, ....should be in our thoughts and prayers at this point.