June 18, 2025, 02:20:00 GMT
permalink Post: 11904840
Slf
I have read that below 400 ft the crew sit on their hands.
I have read that if there is a loss of thrust the crew will firewall the thrust levers.
Everything, the rat,the flightpath,grandma hearing no sound, points to almost simultaneous loss of thrust shortly after rotation.
So, if the recorded data shows the crew firewall the t/l but the engines didn't respond, and the recorded data didn't give any causality, wouldn't you have to ground the fleet ?
I have read that below 400 ft the crew sit on their hands.
I have read that if there is a loss of thrust the crew will firewall the thrust levers.
Everything, the rat,the flightpath,grandma hearing no sound, points to almost simultaneous loss of thrust shortly after rotation.
So, if the recorded data shows the crew firewall the t/l but the engines didn't respond, and the recorded data didn't give any causality, wouldn't you have to ground the fleet ?
I operate under the assumption that the civil aviation authority in India take their job seriously, as do the other major players who have arrived to assist.
I hate to say it, but this is rapidly turning into the same hamster wheel as the first accident thread - with the same questions being asked multiple times, after having already been answered multiple times, and people simply repeating the same theories and postulations over and over again.
Maybe it's time to shut this down again until we hear something meaningful from the Indian investigators.
Maybe it's time to shut this down again until we hear something meaningful from the Indian investigators.
Subjects: None
June 18, 2025, 03:34:00 GMT
permalink Post: 11904871
In the US at least, unions would heavily object to 4k cams everywhere at an airport. Inevitable, the footage would be used by corporate to critique pilots. Some how, some way, the bean counters would find a way to monitor the footage to try and save a penny. There have been many calls to place cameras in the cockpits.....100% unions would fight this and be willing to strike over this.
But that's really a separate topic.
Subjects: None
June 18, 2025, 14:17:00 GMT
permalink Post: 11905287
Well,
tdracer
worked on engine/airframe integration for Boeing. He did that for the GEnx on the B747-8. I would guess he knows more about those systems than some guy with an A&P badge.
They get to look into all of the various write-ups from the pilots when the aircraft and its systems don't work quite as they are expected to.
Let's not dismiss that kind of input without due consideration for what it looks like from the point of view of someone whose task it is to keep things working.
Pilots run into similar oddities - well, it's supposed to do this, per the manual, but it's doing something differently - now and again, right?
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): GEnx (ALL)
June 18, 2025, 15:34:00 GMT
permalink Post: 11905339
Let's not run down the rat hole of "the journos once again got it wrong with terminology" as they so often do.
For the level of precision that they are held to, they are close enough.
For our purposes, no, they are not.
For the level of precision that they are held to, they are close enough.
For our purposes, no, they are not.
Subjects: None
June 19, 2025, 14:43:00 GMT
permalink Post: 11906080
Another user then brought up an iPhone. That notion would, of course, be dramatic\x97but how unlikely is it really that after approximately 10,000 actuations between December 2013 and June 2025, the two FCS no longer lock perfectly? Considering all of this, I find it quite conceivable that the A/T slightly reduced thrust in the first seconds after VR (e.g., if an incorrect target altitude had been entered) and that an object lying between the thrust levers and the FCS could have pushed the FCS into the \x93Off\x94 position. Due to the buttons on top of the switches, which provide some resistance, it\x92s even possible that the object both pulled and pushed them.
On both switches.
The above is also, consistent with your caveat, a speculation.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Maintenance Error
June 19, 2025, 15:32:00 GMT
permalink Post: 11906114
Admin note: we keep getting these "vapour lock" posts from various posters. It has gotten mentioned with some frequency by some posters, and it gets removed as noise. That's why you aren't seeing it.
Roseland, while I am not trying to pick on you, how familiar are you with the 787-8's fuel system?
Can you trace a drop of fuel from the refueling opening to the time of exhaust out the back end of the GE engine?
I can't. (There was I time I could on a few of the aircraft that I flew, but it's been some years).
Can you cite any technical bulletins or ADs for the 787-8 that point to vapour lock hazards / instances / cautions, etcetera.
If so, then back up your speculation with that kind of useful reference.
The above is an appeal to all posters to do as tdracer did in the opening post of this (second) thread: offer informed speculation where speculation arises in the course of discussing this tragic accident.
Roseland, while I am not trying to pick on you, how familiar are you with the 787-8's fuel system?
Can you trace a drop of fuel from the refueling opening to the time of exhaust out the back end of the GE engine?
I can't. (There was I time I could on a few of the aircraft that I flew, but it's been some years).
Can you cite any technical bulletins or ADs for the 787-8 that point to vapour lock hazards / instances / cautions, etcetera.
If so, then back up your speculation with that kind of useful reference.
The above is an appeal to all posters to do as tdracer did in the opening post of this (second) thread: offer informed speculation where speculation arises in the course of discussing this tragic accident.
Subjects: None
June 19, 2025, 16:21:00 GMT
permalink Post: 11906173
Thank you for explaining why I'm not seeing references to vapour lock.
To answer your question regarding the 787-8 fuel system, I have spent much of the last week reading this thread and looking up what I didn't know.
I had thought vapour lock, whilst very unlikely, might account for the simultaneous flame out, but then watched Captain Steeeve's video on YouTube "What Really Causes Dual Engines Failure? | Air India 171 Update".
It would be helpful if the theory could be discounted (with reasoning) and then I (and I suspect others) would learn why it is less plausible than double-this or double-that.
I cannot back up my hypothesis with any AD's, but then if this problem had happened before I guess we wouldn't still be wondering what caused it.
If it was a truly stupid theory, I apologise for wasting people's time, but like many on this thread I'm here to learn.
To answer your question regarding the 787-8 fuel system, I have spent much of the last week reading this thread and looking up what I didn't know.
I had thought vapour lock, whilst very unlikely, might account for the simultaneous flame out, but then watched Captain Steeeve's video on YouTube "What Really Causes Dual Engines Failure? | Air India 171 Update".
It would be helpful if the theory could be discounted (with reasoning) and then I (and I suspect others) would learn why it is less plausible than double-this or double-that.
I cannot back up my hypothesis with any AD's, but then if this problem had happened before I guess we wouldn't still be wondering what caused it.
If it was a truly stupid theory, I apologise for wasting people's time, but like many on this thread I'm here to learn.
Did you find Musician 's post about Fuel Temperature and Thermal Buffer fuel useful? I did.
I left your post up, rather than deleting it, for a couple of reasons - that response is the kind of thing I was hoping to elicit.
Subjects: None
June 20, 2025, 13:00:00 GMT
permalink Post: 11906961
We can stow the discussion of MH 370's satnav signals now. I think the points have been made and aren't really germane to the accident in this thread.
Subjects: None
June 21, 2025, 13:43:00 GMT
permalink Post: 11907761
For Cloud Chasing:
Which media sources? (Article source and date would be helpful).
Any number of posts in both threads have offered the estimation that the flight would have not had additional fuel, and thus a "fill all the way up with fuel" assumption wasn't warranted.
If the reports you mention are credible (rather than mere speculation and rumor) that would be of interest.
The actual fuel load will, in time, be known once the FDR info is processes in full.
Which media sources? (Article source and date would be helpful).
Any number of posts in both threads have offered the estimation that the flight would have not had additional fuel, and thus a "fill all the way up with fuel" assumption wasn't warranted.
If the reports you mention are credible (rather than mere speculation and rumor) that would be of interest.
The actual fuel load will, in time, be known once the FDR info is processes in full.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FDR
June 21, 2025, 14:05:00 GMT
permalink Post: 11907781
The situation with reading the flight recorders seem increasingly suspicious to me. As of yesterday, they're still dithering about whether to send them to the USA? Is this about India not wanting to reveal their smart new facility can't do the job? Or unwillingness to trust the US/Boeing? Or some other kind of argument? It seems ridiculous to me that no decision has been made about the boxes nine days after the crash and the rapidly discovered recorders.
India to decide on overseas analysis of Air India crash flight recorders
India to decide on overseas analysis of Air India crash flight recorders
Note this excerpt from your linked article:
India's Aircraft Accident Investigation Bureau (AAIB) is yet to decide whether flight data and cockpit voice recorders from the Air India flight that crashed last Thursday will be sent overseas for decoding and analysis. {remove crash generalities} Some media outlets reported that the black boxes are being sent abroad, but the ministry of civil aviation clarified that no final decision has been made.The ministry
said
the AAIB will determine the location for analysis after a "due assessment of technical, safety, and security factors".
1. They'd rather do things deliberately, and get it right, than to make a slight rush and get something wrong (even a little bit wrong)
2. The political leadership are sensitive to how the information age, and social media, amplifies even the slightest misstatement.
3. If they can do it in house then why not do it in house? Why add further delay by transferring the recorder and risk accidents in handling during transit?
4. They are under a timeline set by ICAO, not the time line that your, or my, or "the public's" hunger for information and impatience sets.
Let's give them the benefit of the doubt.
Last edited by T28B; 21st June 2025 at 14:13 . Reason: punctuation errors
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): AAIB (All) DFDR ICAO
June 21, 2025, 14:55:00 GMT
permalink Post: 11907816
sabenaboy
That question has been asked with some frequency in both threads.
So far, "unknown" is the correct answer.
Were there another person, one expects that evidence will be found as the CVR data is deciphered by the investigating team.
That question has been asked with some frequency in both threads.
So far, "unknown" is the correct answer.
Were there another person, one expects that evidence will be found as the CVR data is deciphered by the investigating team.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR
June 21, 2025, 16:28:00 GMT
permalink Post: 11907889
New Delhi: Bookings for Air India flights have declined by around 20 per cent on domestic as well as as international routes while the average fares have dropped by 8-15 per cent in the aftermath of the Boeing 787-8 Dreamliner crash in Ahmedabad ...
https://english.mathrubhumi.com/news...crash-plziylbe
https://english.mathrubhumi.com/news...crash-plziylbe
While it is a public statement, I'll offer to you that it is neither accurate enough, nor precise enough, for our purposes as people here on PPRuNe discuss aircraft performance.
Subjects: None
June 21, 2025, 17:45:00 GMT
permalink Post: 11907933
Not
confirmed
. What is apparent is a (substantial) loss of thrust. That's what one can say with some certainty.
That has already been discussed, and there has been abundant comment. Suggest you go back and review the original thread, and this one as well.
Thank you for your interest.
if so, why weren't people commenting on this from the videos of the incident (if the audio was good enough to detect the RAT then surely it was good enough to tell whether the engines were running).
Thank you for your patience!
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Dual Engine Failure Engine Failure (All) Engine Shutdown RAT (All)
June 30, 2025, 01:29:00 GMT
permalink Post: 11913315
As neither mod nor admin
You left out this part: over a populated area that was somewhat built up.
That adds a degree of difficulty to the attempt, with a modest amount of energy and altitude with which to work.
(They hit a building on the way down; some of the casualties were people on the ground).
OK, from my standpoint as a curious observer, what would their options be? They don't have engines to provide thrust, they don't have altitude to lower the nose and gain speed, and they don't have the speed to pull the nose up and extend the glide? All while trying to troubleshoot the same problem we've collectively taken 2 weeks to not understand.
That adds a degree of difficulty to the attempt, with a modest amount of energy and altitude with which to work.
(They hit a building on the way down; some of the casualties were people on the ground).
Subjects: None
July 01, 2025, 15:31:00 GMT
permalink Post: 11914337
Gets tiring correcting glaring errors such as the recent one wrongly asserting separate tanks for each engine is mandatory on TO or that it is routine to turn centre pumps on at 10,000'. Many of us just read it and say "that is clearly BS", "The person has not read the thread", then move on looking for some actual updated information, or news, while not speculating at all.
We'll take a brief pause in hopes of some fresh info from the investigating authority.
Come back tomorrow, this has turned back into a Hamsterwheel.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Thread Closure
July 05, 2025, 14:17:00 GMT
permalink Post: 11916419
A brief summary of what is in this article.
https://www.ndtv.com/india-news/air-...-found-8812035
https://www.ndtv.com/india-news/air-...-found-8812035
A week after the crash of AI-171 on June 12, at least three Air India training pilots on the airline's Boeing 787 fleet attempted to recreate likely scenarios in Mumbai that resulted in the accident in which 260 people were killed. The pilots attempted to simulate electrical failures that could cause a dual-engine flame-out, resulting in an inability of the aircraft to climb post takeoff.
They were unsuccessful .
They were unsuccessful .
- To ensure they were accurate in their simulation scenarios, the pilots replicated the precise trim sheet data of AI-171. A trim sheet is a document used in aviation to calculate and record an aircraft's weight and balance, ensuring the center of gravity is within safe limits for takeoff, flight, and landing. The trainer-pilots also simulated the failure of a single engine, left the undercarriage of the aircraft down, and retracted the flaps of the 787 completely.
- What's more, an improper take-off flap configuration was also selected. This would make it even more challenging for the 787 to climb away on a single engine. Takeoff flaps are adjustable surfaces on an aircraft's wings that are extended during takeoff to increase lift, or the ability of an aircraft to climb. In all of the scenarios described here, AI-171, with a single operational engine, was able to gain altitude safely.
- Air India's Boeing 787-8's General Electric GEnx-1B67-K turbo-fans have been uprated to produce a significant 70,000 pounds of thrust each. These are among the most powerful engines developed for civilian aircraft in the class of Boeing 787.
- Pilots on Air India's Boeing 787 fleet are not trained to deal with a dual-engine failure at an altitude of less than 400 feet, as in the case of AI-171. This would be considered 'negative training', in other words, training for scenarios where the chances of successful recovery are technically not possible. Put simply, a dual-engine failure at the altitude AI-171 was flying in, would have likely resulted in a crash.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): AI171 Simulation Scenarios
July 12, 2025, 17:35:00 GMT
permalink Post: 11920706
Good afternoon esteemed colleagues, the thread is re opened.
Please keep it professional.
Thanks in advance.
T28B
Please keep it professional.
Thanks in advance.
T28B
Subjects: None
July 12, 2025, 20:49:00 GMT
permalink Post: 11920823
(The above posted as neither mod nor admin, to be clear).
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Fuel Cutoff Switches
July 13, 2025, 15:42:00 GMT
permalink Post: 11921402
2. If you can recall: were they able to relight the engine that went to zero thrust?
(Being at cruise altitude they had time and altitude to work with, which AI 171 crew didn't).
3. Thank you for sharing that related event.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Relight Spar Valves
July 13, 2025, 21:53:00 GMT
permalink Post: 11921705
My curiosity awoken, I went back and checked the first few pages of the report. They (Indian ALPA) were not mentioned in the written material as one of the parties to the investigation, for what it is worth, unless they are indirectly covered in the "experienced pilots" noted on page 5 (right before the tabulation of injuries).
Subjects: None