July 15, 2025, 17:40:00 GMT
permalink Post: 11923111
Since the preliminary report neglected including when the RAT deployment occurred, I've tried to estimate it based on the picture they did include:
Baro altitude should be around 150ft; using the public cctv video, I estimate this picture was taken between 4-7 seconds after rotation. A wide range, but that was the best estimate I could come up with. Maybe someone else could narrow it down further.
Baro altitude should be around 150ft; using the public cctv video, I estimate this picture was taken between 4-7 seconds after rotation. A wide range, but that was the best estimate I could come up with. Maybe someone else could narrow it down further.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Preliminary Report RAT (All) RAT (Deployment)
July 15, 2025, 21:55:00 GMT
permalink Post: 11923297
In my opinion, not enough attention is being paid to why the Pilot Monitoring might have *had to* execute the memory items for dual-engine failure.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches Memory Items Preliminary Report RUN/CUTOFF
July 15, 2025, 22:09:00 GMT
permalink Post: 11923308
That's on the EAFR. With their headsets on, are B787 pilots even able to hear the engines on the flight deck, over the wind noise and their headset sidetone? Genuinely asking - I don't know.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR EAFR
July 15, 2025, 23:10:00 GMT
permalink Post: 11923335
I do, I work on Level D sound and communications systems for full flight simulators, designing the sound models and communications as used in many of the worlds FFS, including the 787.
The overall sound environment of the 787 is surprisingly quiet, but at takeoff thrust the engines are easily heard, even with the headsets on - these are typically light-weight over-ear units. Aerodynamic noise is not really significant until the aircraft is faster/higher.
In this accident case, the engine spool-down should have been a noticeable sound cue.
- GY
The overall sound environment of the 787 is surprisingly quiet, but at takeoff thrust the engines are easily heard, even with the headsets on - these are typically light-weight over-ear units. Aerodynamic noise is not really significant until the aircraft is faster/higher.
In this accident case, the engine spool-down should have been a noticeable sound cue.
- GY
If a fault caused the pack compressors to go quiet, could that be mistaken as engine loss? Say on the left side?
Subjects: None
July 16, 2025, 01:18:00 GMT
permalink Post: 11923375
The thought did pass my mind that the original report may have been translated by machine into English and lost some extremely important nuance that has led some up the wrong garden path. How? Look at one of the headings - '5. Damages'. Plural instead of singular. Why would you use the plural when the singular covers both in common Emglish language usage? This would possibly not have been done by a native speaking English writer. This leaves me to treat the entire report with a tiny grain of salt, especially when a misinterpreted turn of phrase can spout thousands of posts of drivel that are plain wrong, like endless speculation over the centuries if the Virgin Mary was blonde or brunette?
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Parameters
July 16, 2025, 01:55:00 GMT
permalink Post: 11923383
Since the preliminary report neglected including when the RAT deployment occurred, I've tried to estimate it based on the picture they did include:
Baro altitude should be around 150ft; using the public cctv video, I estimate this picture was taken between 4-7 seconds after rotation. A wide range, but that was the best estimate I could come up with. Maybe someone else could narrow it down further.
Baro altitude should be around 150ft; using the public cctv video, I estimate this picture was taken between 4-7 seconds after rotation. A wide range, but that was the best estimate I could come up with. Maybe someone else could narrow it down further.
1. ADSB readouts - according to FlightRadar24, the last ADSB transmission was at 71ft AGL. Is that significant given the RAT is seen already deployed at 150ft AGL per the estimate above? At 71ft AGL, the wheels are about 40-50ft off the ground, assuming aircraft attitude is unchanged between there and this image. Is that 1 or 2 seconds after rotation? Does this imply electrical issues?
1a. The timings for ADSB transmissions outlined by MrShed are not in sync with the estimates above - people have talked about a time shift in this thread. I do believe ADSB timestamps are by the receiving station.
2. The preliminary report timings from the EAFR for E2 fuel cutoff switch RUN -> CUTOFF to the RAT supplying hydraulic power disagree with the lower end of the 4-7s estimate above, and are only consistent if this picture was taken 6-7 seconds after rotation, in my opinion, because of the time (4-5s) it would take to cut off the fuel to E2, spool down to where the VFSGs stop providing AC power, and RAT deployment.
3. The Preliminary Report mentions that the RAT deployed "immediately after" lift-off. Again, I have to wonder, why didn't they provide the RAT deployment timestamp, even relative to rotation? If this is in fact the case, does this imply electrical issues, in line with the last ADSB altitude reading?
FR24 article https://www.flightradar24.com/blog/f...rom-ahmedabad/
Last edited by appruser; 16th July 2025 at 01:57 . Reason: Added link to FR24 blog post
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): ADSB EAFR FlightRadar24 Fuel (All) Fuel Cutoff Fuel Cutoff Switches Hydraulic Failure (All) Preliminary Report RAT (All) RAT (Deployment) RUN/CUTOFF
July 18, 2025, 00:25:00 GMT
permalink Post: 11924773
So I've looked again and I think that basically the ADS-B data is 5 seconds out.
So in the diagram (can't modify right now but I will), the blue bar starts at 5 and ends at 13, max altitude marker at 8.
That would tie in with loss of power.
It would put, interestingly, engine cutoffs right at the earliest opportunity within the window available with sampling etc.
(Incidentally an apology to Musician who I incorrectly told earlier that such a movement would be inconsistent with max altitude record, I can see clearly now this isn't the case!).
So in the diagram (can't modify right now but I will), the blue bar starts at 5 and ends at 13, max altitude marker at 8.
That would tie in with loss of power.
It would put, interestingly, engine cutoffs right at the earliest opportunity within the window available with sampling etc.
(Incidentally an apology to Musician who I incorrectly told earlier that such a movement would be inconsistent with max altitude record, I can see clearly now this isn't the case!).
I think for various reasons the ADSB data's absolute values are offset by some amount, for possibly all of the parameters. But there should be consistency in the deltas for the timestamp (by receiving station), the raw baro altitude, the Flightradar24 AGL values, and the airspeed. Flightradar24 themselves note that for altitude " ... the data is not above ground level, but it is consistent to itself."
08:08:46.55 ... 575ft ... 21ft ... 184kt
08:08:48.14 ... 600ft ... 46ft ... 179kt
08:08:48.61 ... 600ft ... 46ft ... 177kt
08:08:49.01 ... 600ft ... 46ft ... 177kt
08:08:49.46 ... 625ft ... 71ft ... 177kt
08:08:49.92 ... 625ft ... 71ft ... 174kt
08:08:50.39 ... 625ft ... 71ft ... 174kt
08:08:50.87 ... 625ft ... 71ft ... 172kt
From the Preliminary Report's airport cctv picture, the RAT was seen deployed at, by my estimate here , 150ft baro altitude, between 4-7 seconds after rotation. So the ADSB readings have to be prior to that.
What's interesting is that the ADSB data covers:
- 4-5 seconds of time (let's approximate 4 seconds from 46.55 to 50.55, ignoring the 0.32s for the moment)
- 50ft of altitude gain
- Declining airspeed from the 1st reading to the last in this final segment from the runway.
Big questions in my mind:
1. If the loss of ADSB corresponds to the E1/E2Fuel Cutoff switches being moved from RUN -> CUTOFF, why is the airspeed declining for the prior 4 seconds?
2. In 4 seconds, why is there only 50ft of altitude gain? that seems odd.
3. To account for only 50ft of alt gain, if we assume the 1st reading is on the runway just before rotation, the intermediate +25ft alt gain is at rotation (Nose up but MLG still on the runway), and the last 4 readings are in the air (nose up an additional 25ft), that means that 1 second or less after lift-off, ADSB was lost - this is before E1/E2 FCO RUN-> CUTOFF.
It's just weird .
Last edited by appruser; 18th July 2025 at 00:41 . Reason: added a comma for clarity
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): ADSB FlightRadar24 Fuel (All) Fuel Cutoff Switches Parameters RAT (All) RAT (Deployment) RUN/CUTOFF
July 18, 2025, 03:43:00 GMT
permalink Post: 11924815
I am not sure why 50 feet in 4 seconds seems odd right after liftoff in a heavy aircraft. That corresponds to 750 FPM. Seems entirely normal to me. The rate would have been increasing as the timeline advanced. I would also point out that RAT deployment verses the rat coming online fully are two different times. When that RAT is singled to deploy it bangs out nearly instantly. It begins producing its rated electrical and hydraulic power sometime after deployment.
The widely watched video shows a very normal initial rotation and climb.
The widely watched video shows a very normal initial rotation and climb.
Since the preliminary report states E2 cutoff after 3-4 seconds after lift-off, if that cutoff corresponds to ADSB interruption and which itself was only transmitting for 4 seconds, then 50ft after liftoff is a bit anemic?
But if we include the first 25ft after rotation but before lift-off, then, because the ADSB duration is only 4 seconds, it means that ADSB was interrupted before the E2 FCO operation. I don't know if there is a sliding window - part after rotation, part after lift-off that might meet all of these constraints.
That still leaves unexplained the declining airspeed seen in the ADSB data... did prior discussions on the ADSB data cover this? is there a good explanation?
Last edited by appruser; 18th July 2025 at 04:03 . Reason: fixed heights
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): ADSB Fuel (All) Fuel Cutoff Switches Hydraulic Failure (All) Preliminary Report RAT (All) RAT (Deployment)
July 18, 2025, 03:45:00 GMT
permalink Post: 11924816
This statement has lots of merit.
Correct. And we're going to actively avoid getting near that theme in posts here. For reasons we can generally understand, the circumstances of this sad event have migrated away from being primarily aviation (the report does not suggest a defect with the airplane, and at least one pilot was obviously doing their very best). The report leads us into massive speculation territory, and outside the specialties of nearly all of us. None of us want to have PPRuNe become a source of information (correct, or otherwise) which may be used against a fellow pilot.
During a relaxing 36 hours away from the internet, away with Mrs. DAR, I reflected. I'm wondering to myself what this thread can continue to do [good] for we pilots, which it has not already done? It is now a repository of some good, and some less than good information. Are we contributing more to good outcomes for our industry by speculating, which theories may never be able to be validated?
Should we be closing this thread until something substantively new and authoritative can be added to the discussion? If keeping it open, what is served?
P.S.: After some very useful discussions, both with learned members of our group here, and some wise advisors outside this forum, I will take responsibility for now formally requesting of our members that future posts about this accident, or other [possible] intentional pilot act aviation crashes, not use the words: "suicide" nor "murder" at all - none, not at all, don't type the word.
A person may be described as "taking their own life" if that is a known intentional fact. For this event, the engines shutdown is not known to be a deliberate act. The two words now not to be used do have legal implications, and we're not going there. This is a pilot forum, not a legal forum. The accusation that a pilot intentionally shut down the two engines is not provable - it could have been a cockpit error. We may never know. It's time to stop talking this way.
I (and the other mods) are not going to go backward to sanitize what has gone before in these threads, it's just too much work, and trying to erase words is not really going to help. On the other hand, going forward, we're not going to perpetuate these words and theme.
If you have a genuine disagreement with me on this, I suppose I have to accept your PM on the topic. So far, I have replied every PM, out of courtesy. But I'd rather not explain again in a PM, what I have just explained here - 'cause that's all I've got. There's a line, we all know where it is, we're going to stay on the professional pilot peer side of it here - right?
So, as I have requested that these terms no longer be used, and I cannot imagine anything truly new to be discussed, I'm going to turn in, with the hope that posters might make the very bare minimum of meaningful posts, if any at all. No more questions about how the switches work, and speculated failure modes ('cause they've all been discussed far too much), no more medical speculation ('cause we have no facts, and this was a peer), and so on - you get the idea.... This, is moderation.
When a final report is released, we'll probably have more to discuss.
In the hours to come we mods will have given this all more thought, the thread may close - unless it does not have to.... please....
Pilot DAR,
One of your moderating team
Correct. And we're going to actively avoid getting near that theme in posts here. For reasons we can generally understand, the circumstances of this sad event have migrated away from being primarily aviation (the report does not suggest a defect with the airplane, and at least one pilot was obviously doing their very best). The report leads us into massive speculation territory, and outside the specialties of nearly all of us. None of us want to have PPRuNe become a source of information (correct, or otherwise) which may be used against a fellow pilot.
During a relaxing 36 hours away from the internet, away with Mrs. DAR, I reflected. I'm wondering to myself what this thread can continue to do [good] for we pilots, which it has not already done? It is now a repository of some good, and some less than good information. Are we contributing more to good outcomes for our industry by speculating, which theories may never be able to be validated?
Should we be closing this thread until something substantively new and authoritative can be added to the discussion? If keeping it open, what is served?
P.S.: After some very useful discussions, both with learned members of our group here, and some wise advisors outside this forum, I will take responsibility for now formally requesting of our members that future posts about this accident, or other [possible] intentional pilot act aviation crashes, not use the words: "suicide" nor "murder" at all - none, not at all, don't type the word.
A person may be described as "taking their own life" if that is a known intentional fact. For this event, the engines shutdown is not known to be a deliberate act. The two words now not to be used do have legal implications, and we're not going there. This is a pilot forum, not a legal forum. The accusation that a pilot intentionally shut down the two engines is not provable - it could have been a cockpit error. We may never know. It's time to stop talking this way.
I (and the other mods) are not going to go backward to sanitize what has gone before in these threads, it's just too much work, and trying to erase words is not really going to help. On the other hand, going forward, we're not going to perpetuate these words and theme.
If you have a genuine disagreement with me on this, I suppose I have to accept your PM on the topic. So far, I have replied every PM, out of courtesy. But I'd rather not explain again in a PM, what I have just explained here - 'cause that's all I've got. There's a line, we all know where it is, we're going to stay on the professional pilot peer side of it here - right?
So, as I have requested that these terms no longer be used, and I cannot imagine anything truly new to be discussed, I'm going to turn in, with the hope that posters might make the very bare minimum of meaningful posts, if any at all. No more questions about how the switches work, and speculated failure modes ('cause they've all been discussed far too much), no more medical speculation ('cause we have no facts, and this was a peer), and so on - you get the idea.... This, is moderation.
When a final report is released, we'll probably have more to discuss.
In the hours to come we mods will have given this all more thought, the thread may close - unless it does not have to.... please....
Pilot DAR,
One of your moderating team
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Thread Moderation