Posts about: "RAT (All)" [Posts: 607 Pages: 31]

Compton3fox
2025-06-13T07:24:00
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Post: 11900099
Originally Posted by Waterbomber2
My theory on this is a wrong weight/temperature entry, too much derating, attempted take-off in too low an energy state and subsequent departure stall.

From the airport cam video, the aircraft seems to stick off just at the end of the runway.
Both engines are working at full blast until at least obstacle clearance height, they kick up unusual amounts of dust for a take-off.

Theoretical sequence of events:
1. Pilots entered the wrong take off perf data
2. During the take-off roll they realize that the aircraft isn't picking up enough speed but too late to reject and firewall the throttles
3. They use up the whole runway and get the aircraft off the ground in ground effect
4. Ground effect ends and they fail to maintain a positive rate of climb, hence gears stay down
5. Aircraft stalls and sinks into the ground

Textbook departure stall and failure to pitch down to recover from it.
So why did the RAT deploy?
Bluffontheriver123
2025-06-13T07:30:00
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Post: 11900107
Can the RAT be deployed manually\x85
Originally Posted by Saintly
Sounds like a double engine failure. The RAT was deployed automatically. What caused engine failure who knows..
culzean12
2025-06-13T07:31:00
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Post: 11900108
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.

2 users liked this post.

FullWings
2025-06-13T07:36:00
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Post: 11900111
Originally Posted by m0nkfish
People on here seem convinced the RAT was deployed because they\x92ve seen it/heard it so many times before. They may be right. But if they are, then it means the RAT has deployed countless times before without both engines having failed, so it doesn\x92t definitively tell us anything.
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.

2 users liked this post.

retired guy
2025-06-13T07:36:00
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Post: 11900113
The latest hi res video does have audio and very clear. You can hear a RAT sound as it passes by or certainly a deep propeller sound, And a blob where the RAT would be. Only the FDR will help here, That would point to total power loss. But the sudden loss of lift apparent in the video doesn't look like power loss.
Icarus2001
2025-06-13T07:50:00
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Post: 11900127
Every Boeing (and Airbus) twin plus the 747-8 has a RAT -.
The Boeing 717?
The Boeing 737?
The Airbus 220?

​​​​​​​ Is there a reason the setting should not default after a landing to ‘Input required’?
​​​​​​​Yes, yes there is. Because it is SOP to set the cleared altitude when receiving the airways clearance, on the bay or PDC. It is then covered in the departure briefing. Stop trying to reinvent the wheel.

1 user liked this post.

Someone Somewhere
2025-06-13T08:06:00
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Post: 11900136
Originally Posted by Icarus2001
The Boeing 717?
The Boeing 737?
The Airbus 220?
A220 has a RAT - so does the E-jets and the Sukhoi Superjet. You're right on the 737 and I'd forgotten the 717...
Spoiler
 


Last edited by Someone Somewhere; 13th Jun 2025 at 08:19 .
TBL Warrior
2025-06-13T08:06:00
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Post: 11900137
Originally Posted by tdracer
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.
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 😂

6 users liked this post.

Captain Biggles 101
2025-06-13T08:07:00
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Post: 11900140
There isn't enough clarity on numerous issues, and without answers to the following, zero conclusions can be made as to a possible cause. This is definitely one that could go in numerous directions. Anyone claiming to have the definitive answers must have the FDR data, and I'm assuming that shouldn't take too long to be located and analysed.

1a. Were flaps deployed at start of take off roll?
1b. Were flaps retracted coinciding with climb rate reduction?
2. Did the RAT definitely deploy? The videos are grainy low quality. AI improvement surely isn't reliable.
3. If the RAT deployed, would that indicate complete power loss?
4. Was there any other audio indicating thrust loss or variations during departure?
5. Can we confirm the pilot Mayday indicating thrust loss? If so, that needs investigation as a first priority. The pilot was telling us the cause. Unless we have alternative information he should be believed.
6. Why was the gear not retracted? Distraction, hydraulic failure, flap instead of gear, intentionally, the possibilities are endless.
7. If complete thrust loss occurred, other than a severe fuel issue, what could cause simultaneous flameout? That would be almost unimaginable, yet this is what the pilot allergy said happened. It would have massive ramifications if that gets confirmed.

I don't think the video clips we have are clear enough to say anything at all at this stage. Flaps are hard to see on 787 imo for departure settings. All I can say is it appeared to climb well in the first seconds, then coinciding with the point that gear would usually be retracted, lift appears to very quickly be lost. That indicates sudden speed loss, or lift loss. Speed loss would be thrust, lift loss would be flap retraction if thrust was still available.

The pilot allegedly reported thrust loss, that should be highest on the list of causes imo. In the case of double engine failure without any apparent outside influence visible on videos, that would be quite something for investigators to fathom.

I don't know if anyone has data to show speed trend at the point the aircraft starts to descend, or a better audio for thrust variations at that point. I'm guessing that the update frequency on FR24 would be too slow to show that sudden change at the highest point achieved.

We'll have the answers soon enough, all I can say is there appears to be no clear answers here without the data recorders or clear improved information. Indeed no conclusions whatsoever can be made as to crew actions either.

RIP crew and passengers, condolences to the families.

1 user liked this post.

Gin Jockey
2025-06-13T08:09:00
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Post: 11900142
Originally Posted by oceancrosser
And your post squarly falls within the categories you describe in your first paragraph. I have, and still am flying 757/767s, flown probably around 40 examples from early to late production planes AND EVERY SINGLE ONE had a RAT.
I can only reiterate what I said, you can disagree if you like, I don\x92t have any current 767 documentation anymore (been off it for almost 10 years), I can 100% say that across all of the the 30+ airframes, 2 different models -200/300ER and 3 engine combinations (PW, GE, RR) that I flew... NONE OF THOSE 30+ airframes had a RAT. Maybe yours do? I don\x92t know. Feel free to post some 767-200/300 FCOM information if you have it.

What the 767s I flew did have, was a hydraulic generator (or 2 in some cases), but that sure ain\x92t a RAT.
tumtiddle
2025-06-13T08:16:00
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Post: 11900154
Originally Posted by shared reality
Are you kidding? The RAT is deployed (at least on Airbus) when you lose normal electrical supply. This will most likely never (or maybe once) happen in any pilots career.. So you most definitely have not heard "many hundreds" of 777/787 in that abnormal state.

As to the no flaps / flaps debate, time will tell. But what is definitely obvious is that they never raise the gear. Now that is tangible, and to me it seems that initially the aircraft is climbing at a somewhat steady climb until it doesn't.
Having flown both Boeings and Airbus+ numerous other types over the years, on every type I have ever flown the initial action once positive climb is determined, is to raise the gear.
This goes for every takeoff, normal or with failure of any sort (with the exception of a dual engine failure at rotation, which is not the case here, as they initially climbed to xxx hundred feet).
So, initially the gear should have been retracted in order to minimise drag, and the question is, why was it not?

Of course, once the gear is up, and in an instance where you get a dual engine failure at low level (highly rare) over land, then it is good arimanship to extend the gear in order for it to take some of the impact when a forced landing is inevitable. But why they did not raise the gear after rotation is a mystery to me.
I'm afraid you've waded in without reading the rest of the thread. The poster you quoted has already explained he lives on the flight path in Everett or Paine, and so hears the test flights of all the aircraft before delivery to airlines.

23 users liked this post.

MyTH
2025-06-13T08:47:00
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Post: 11900195
RAT? Here\x92s an unprocessed frame from the video. I really don\x92t see that the RAT has deployed.


1 user liked this post.

A4
2025-06-13T08:54:00
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Post: 11900208
Electrical AC loss results in the activation of an emergency geberator driven by the green system.
Which Airbus family is that? On the 319-321 loss of AC1 and AC2 (double gen or dual eng fail) will deploy the RAT.

​​​​​​​A4
lakedude
2025-06-13T09:04:00
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Post: 11900214
Originally Posted by simon001
Probably the best, early stage theory of the the cause that I have seen as yet. By a current 777 captain:

https://www.youtube.com/watch?v=z7EZkungFEE
There is evidence on this thread that flaps were not the issue. The Mayday call and the evidence that the RAT was out is more convincing than a gear/flap mixup. Early on in this thread the gear/flap mixup had a lot of traction but after more photographic evidence surfaced it has more or less been put to rest, for me anyhow.

4 users liked this post.

Ngineer
2025-06-13T09:11:00
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Post: 11900223
I didn\x92t think this could be a dual engine failure related accident until reports of RAT deployment started to gather steam.
A few years back a B787 previously had a dual engine shutdown after rollout when the TR was deployed too quickly and not allowing the air/GND logic time to transition to ground mode before the TR deployed. If the TCMA had inadvertently latched the TR deployment from the previous rollout then it theoretically could be possible to shutdown on transition back to air mode.
Anything is possible with these high tech machines.

2 users liked this post.

flemingcool
2025-06-13T09:26:00
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Post: 11900239
Originally Posted by Ngineer
I didn\x92t think this could be a dual engine failure related accident until reports of RAT deployment started to gather steam.
A few years back a B787 previously had a dual engine shutdown after rollout when the TR was deployed too quickly and not allowing the air/GND logic time to transition to ground mode before the TR deployed. If the TCMA had inadvertently latched the TR deployment from the previous rollout then it theoretically could be possible to shutdown on transition back to air mode.
Anything is possible with these high tech machines.
SLF. I don\x92t know how B787 systems work but if that\x92s correct it must be a possibility. It seems as though engines are working fine until airborne. I\x92d just been asking elsewhere if it were possible that an electrical fault with the software could prevent both engines running? I know they don\x92t require outside power to continue to run, but if software was disrupted by a catastrophic electrical fault (issues reported on previous flight supposedly) would they shut down? But an error in the software could be more likely than the sort of failure requiring multiple backups to also fail I guess, and would also explain the timing of the engines shutting down/throttling back.

RIP to all the victims.
Screamliner
2025-06-13T09:36:00
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Post: 11900252
Hi everyone, 787 driver here, well lets look at the facts we see
very late rotation, but pitch and departure path look like normal up until stalling point.
mayday was called but without clarification or purpose, for me this indicates stress in the flight deck, especially low level
no smoke or fire from engines, I would rule out severe damage or birdstrikes at this point
Flaps 5 departure would be difficult to see as a pixel on a bad video, but they would not have made the rotation at that speed so I assume they used flaps during departure, also you would neglect to ECL's and a config warning
no RAT to be seen either, again ruling out dual engine failure, also the climb would not have been so parabolic
maybe single engine fuel starvation/Mechanical issue/dirty fuel, but seems unlikely, the flight path is too gentle
Gear stays down, and even though the pitch remains the same, they start losing lift and basically stall the aircraft into the ground
don't forget, Air India uses 64/67K engines on they're 787's, with temp of 41 degrees (ambient, so even more above tarmac) and a QNH of 1001, those engines will be pushed to "hard work mode" already

IMHO, two things I could assume happend
- either single engine failure, no pitch adjustment and speed fell below Vstall, OR, most likely
- mixup of Flaps moved to up position in stead of Gear moved to up position, that would clarify the gear, would clarify the loss of lift and that the engines have no smoke, and no RAT,

10 users liked this post.

DaveReidUK
2025-06-13T09:49:00
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Post: 11900263
Originally Posted by Screamliner
no RAT to be seen either
You seem very sure of that, whereas numerous other posts (which I trust you've read) reckon that the RAT could be both seen and heard on some of the many videos.

4 users liked this post.

bobbytables
2025-06-13T10:01:00
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Post: 11900273
Originally Posted by Screamliner
Hi everyone, 787 driver here, well lets look at the facts we see
very late rotation, but pitch and departure path look like normal up until stalling point.
mayday was called but without clarification or purpose, for me this indicates stress in the flight deck, especially low level
no smoke or fire from engines, I would rule out severe damage or birdstrikes at this point
Flaps 5 departure would be difficult to see as a pixel on a bad video, but they would not have made the rotation at that speed so I assume they used flaps during departure, also you would neglect to ECL's and a config warning
no RAT to be seen either, again ruling out dual engine failure, also the climb would not have been so parabolic
maybe single engine fuel starvation/Mechanical issue/dirty fuel, but seems unlikely, the flight path is too gentle
Gear stays down, and even though the pitch remains the same, they start losing lift and basically stall the aircraft into the ground
don't forget, Air India uses 64/67K engines on they're 787's, with temp of 41 degrees (ambient, so even more above tarmac) and a QNH of 1001, those engines will be pushed to "hard work mode" already

IMHO, two things I could assume happend
- either single engine failure, no pitch adjustment and speed fell below Vstall, OR, most likely
- mixup of Flaps moved to up position in stead of Gear moved to up position, that would clarify the gear, would clarify the loss of lift and that the engines have no smoke, and no RAT,
a few things stated as fact there without any evidence to support the assertions.

very late rotation - stated several times on this thread but zero evidence for it and some analysis suggests the rotation was at roughly the same location as previous departures of the same flight

no RAT - others, including one with a lot of experience with the sound of a deployed RAT, insist that it was deployed. The video evidence is unclear.

Not saying you\x92re necessarily wrong about anything but I take issue with those that state as fact things that are not (yet) supported by any evidence at all

18 users liked this post.

Travis Anderson
2025-06-13T10:03:00
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Post: 11900277
Flap - gear mix-up indeed seems most consistent - if there was no RAT. But looks to me their anomaly started when the automation switches from ground to fly mode. So is there some automation that could potentially cut or idle both engines during that transition?

It's just too simple to be true. I expect/hope for some Swiss Cheese type failure.

1 user liked this post.