June 12, 2025, 12:11:00 GMT
permalink Post: 11899141
Like most Boeings, on the 787 you are prevented from selecting the flaps/slats all the way up in one go by the gate at flap 1. If this was a mis-selection by one of the pilots, they would have been prevented from selecting ALL the high lift devices up in one go by the flap 1 gate. Even if you manage to get the lever to the Flaps Up position then below 225kts you should get Slat-Gap protection which maintains MOST of the lift. I have never tried it personally but that's the operation as advertised by Boeing. Would that provide enough lift to save them...... that is really a matter of debate.
The aircraft may have suffered a power loss of one or both engines possibly by bird strike. I have to say that the B787 is the very easiest aircraft I have ever flown when handling an engine failure above V1. The flight path vector and the flight director in the head up display make finessing an engine failure absolute child's play. Having said that the Boeing 787 performance is calculated right to the limits of legal requirement, so there is no scope for mis-handling. If they failed to select the landing gear up, not due to a flap lever mis-selection, but some another distraction, like an engine failure, then the aircraft would struggle to accelerate to V2 to safely climb away.
The B787 derates are calculated to give an acceptable Vmca in the event of an engine failure. That is to say, if you apply any more power asymmetricly the Vmca criteria of up to 5deg of bank towards the live engine will require more control input resulting in more control drag. Our SOP was - If you need it - Use It! Thankfully I never had to find out.
By way of illustration, on the B747-400, leaving the gear down following an engine failure had the same effect as failing two of the four engines.
The aircraft may have suffered a power loss of one or both engines possibly by bird strike. I have to say that the B787 is the very easiest aircraft I have ever flown when handling an engine failure above V1. The flight path vector and the flight director in the head up display make finessing an engine failure absolute child's play. Having said that the Boeing 787 performance is calculated right to the limits of legal requirement, so there is no scope for mis-handling. If they failed to select the landing gear up, not due to a flap lever mis-selection, but some another distraction, like an engine failure, then the aircraft would struggle to accelerate to V2 to safely climb away.
The B787 derates are calculated to give an acceptable Vmca in the event of an engine failure. That is to say, if you apply any more power asymmetricly the Vmca criteria of up to 5deg of bank towards the live engine will require more control input resulting in more control drag. Our SOP was - If you need it - Use It! Thankfully I never had to find out.
By way of illustration, on the B747-400, leaving the gear down following an engine failure had the same effect as failing two of the four engines.
June 12, 2025, 13:13:00 GMT
permalink Post: 11899199
According to FR24 on bluesky, the aircraft used the full runway length:
"We are continuing to process data from receiver sources individually. Additional processing confirms #AI171 departed using the full length of Runway 23 at Ahmedabad. RWY 23 is 11,499 feet long. The aircraft backtracked to the end of the runway before beginning its take off roll."
"We are continuing to process data from receiver sources individually. Additional processing confirms #AI171 departed using the full length of Runway 23 at Ahmedabad. RWY 23 is 11,499 feet long. The aircraft backtracked to the end of the runway before beginning its take off roll."
June 12, 2025, 19:03:00 GMT
permalink Post: 11899609
Don't know the TODA, TORA set up there but don't forget aircraft performance is to hit a 35 foot screen height and the use of reduced thrust means it will be at the very, very end of the runway - it's what's done almost every take-off of a jet to preserve engine performance
June 12, 2025, 19:19:00 GMT
permalink Post: 11899636
Condolences to all the people who have lost loved ones:
I have a question about that: As the plane would have been half fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':
Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?
If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?
I have a question about that: As the plane would have been half fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':
Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?
If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?
Last edited by Obba; 12th June 2025 at 19:49 . Reason: Fuel - 787-8 can hold 126 kl
June 12, 2025, 19:29:00 GMT
permalink Post: 11899647
nothing was normal the plane rotated right at the end of the runway far too late and barely climbed at all for 10 seconds before falling 20 seconds and finally crashing 30 seconds after take off.
The most obvious answer is low power/flaps setting if the engines were weird they would have probably aborted take off. Bird strike/engine issue during take off roll after v1? Super unlikely but never say never
The most obvious answer is low power/flaps setting if the engines were weird they would have probably aborted take off. Bird strike/engine issue during take off roll after v1? Super unlikely but never say never
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.
June 12, 2025, 19:33:00 GMT
permalink Post: 11899652
Condolences to all the people who have lost loved ones:
I have a question about that: As the plane would have been fully fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':
Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?
If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?
I have a question about that: As the plane would have been fully fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':
Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?
If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?
June 12, 2025, 19:33:00 GMT
permalink Post: 11899653
Condolences to all the people who have lost loved ones:
I have a question about that: As the plane would have been fully fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':
Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?
If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?
I have a question about that: As the plane would have been fully fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':
Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?
If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?
June 12, 2025, 20:23:00 GMT
permalink Post: 11899693
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.
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.
June 12, 2025, 20:42:00 GMT
permalink Post: 11899714
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.
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.
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.
June 12, 2025, 20:46:00 GMT
permalink Post: 11899718
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.
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.
June 12, 2025, 22:02:00 GMT
permalink Post: 11899778
OK, I promised some informed speculation when I got back, so here goes:
Disclaimer: never worked the 787, so my detailed knowledge is a bit lacking.
First off, this is perplexing - especially if the RAT was deployed. There is no 'simple' explanation that I can come up with.
GEnx-1B engines have been exceptionally reliable, and the GE carbon composite fan blades are very robust and resistant to bird strike damage (about 15 years after the GE90 entry into service, I remember a GE boast that no GE90 (carbon composite) fan blades had needed to be scrapped due to damage (birdstrike, FOD, etc. - now that was roughly another 15 years ago, so is probably no longer true, but it shows just how robust the carbon composite blades are - far better than the more conventional titanium fan blades).
Not saying it wasn't somehow birdstrike related, just that is very unlikely (then again, all the other explanations I can come up with are also very unlikely
).
Using improper temp when calculating TO performance - after some near misses, Boeing added logic that cross-compares multiple total temp probes - aircraft TAT (I think the 787 uses a single, dual element probe for aircraft TAT, but stand to be corrected) and the temp measured by the engine inlet probes - and puts up a message if they disagree by more than a few degree tolerance - so very, very unlikely.
N1 power setting is somewhat less prone to measurement and power setting errors than EPR (N1 is a much simpler measurement than Rolls EPR) - although even with EPR, problems on both engines at the same time is almost unheard of.
The Auto Thrust (autothrottle) function 'falls asleep' at 60 knots - and doesn't unlock until one of several things happens - 250 knots, a set altitude AGL is exceeded (I'm thinking 3,000 ft. but the memory is fuzzy), thrust levers are moved more than a couple of degrees, or the mode select is changed (memory says that last one is inhibited below 400 ft. AGL). So an Auto Thrust malfunction is also extremely unlikely. Further, a premature thrust lever retard would not explain a RAT deployment.
TO does seem to be very late in the takeoff role - even with a big derate, you still must accelerate fast enough to reach V1 with enough runway to stop - so there is still considerable margin if both engines are operating normally. That makes me wonder if they had the correct TO power setting - but I'm at a loss to explain how they could have fouled that up with all the protections that the 787 puts on that.
If one engine did fail after V1, it's conceivable that they shut down the wrong engine - but since this happened literally seconds after takeoff, it begs the question why they would be in a big hurry to shut down the engine. Short of an engine fire, there is nothing about an engine failure that requires quick action to shut it down - no evidence of an engine fire, and even with an engine fire, you normally have minutes to take action - not seconds.
The one thing I keep thinking about is someone placing both fuel switches to cutoff immediately after TO. Yes, it's happened before (twice - 767s in the early 1980s), but the root causes of that mistake are understood and have been corrected. Hard to explain how it could happen (unless, God forbid, it was intentional).
Disclaimer: never worked the 787, so my detailed knowledge is a bit lacking.
First off, this is perplexing - especially if the RAT was deployed. There is no 'simple' explanation that I can come up with.
GEnx-1B engines have been exceptionally reliable, and the GE carbon composite fan blades are very robust and resistant to bird strike damage (about 15 years after the GE90 entry into service, I remember a GE boast that no GE90 (carbon composite) fan blades had needed to be scrapped due to damage (birdstrike, FOD, etc. - now that was roughly another 15 years ago, so is probably no longer true, but it shows just how robust the carbon composite blades are - far better than the more conventional titanium fan blades).
Not saying it wasn't somehow birdstrike related, just that is very unlikely (then again, all the other explanations I can come up with are also very unlikely
).
Using improper temp when calculating TO performance - after some near misses, Boeing added logic that cross-compares multiple total temp probes - aircraft TAT (I think the 787 uses a single, dual element probe for aircraft TAT, but stand to be corrected) and the temp measured by the engine inlet probes - and puts up a message if they disagree by more than a few degree tolerance - so very, very unlikely.
N1 power setting is somewhat less prone to measurement and power setting errors than EPR (N1 is a much simpler measurement than Rolls EPR) - although even with EPR, problems on both engines at the same time is almost unheard of.
The Auto Thrust (autothrottle) function 'falls asleep' at 60 knots - and doesn't unlock until one of several things happens - 250 knots, a set altitude AGL is exceeded (I'm thinking 3,000 ft. but the memory is fuzzy), thrust levers are moved more than a couple of degrees, or the mode select is changed (memory says that last one is inhibited below 400 ft. AGL). So an Auto Thrust malfunction is also extremely unlikely. Further, a premature thrust lever retard would not explain a RAT deployment.
TO does seem to be very late in the takeoff role - even with a big derate, you still must accelerate fast enough to reach V1 with enough runway to stop - so there is still considerable margin if both engines are operating normally. That makes me wonder if they had the correct TO power setting - but I'm at a loss to explain how they could have fouled that up with all the protections that the 787 puts on that.
If one engine did fail after V1, it's conceivable that they shut down the wrong engine - but since this happened literally seconds after takeoff, it begs the question why they would be in a big hurry to shut down the engine. Short of an engine fire, there is nothing about an engine failure that requires quick action to shut it down - no evidence of an engine fire, and even with an engine fire, you normally have minutes to take action - not seconds.
The one thing I keep thinking about is someone placing both fuel switches to cutoff immediately after TO. Yes, it's happened before (twice - 767s in the early 1980s), but the root causes of that mistake are understood and have been corrected. Hard to explain how it could happen (unless, God forbid, it was intentional).
Last edited by T28B; 12th June 2025 at 22:21 . Reason: white space is your friend, and is reader-friendly
June 13, 2025, 02:34:00 GMT
permalink Post: 11899935
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
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
Last edited by bbofh; 13th June 2025 at 07:53 .
June 13, 2025, 03:02:00 GMT
permalink Post: 11899948
OK, I promised some informed speculation when I got back, so here goes:
Disclaimer: never worked the 787, so my detailed knowledge is a bit lacking.
First off, this is perplexing - especially if the RAT was deployed. There is no 'simple' explanation that I can come up with.
GEnx-1B engines have been exceptionally reliable, and the GE carbon composite fan blades are very robust and resistant to bird strike damage (about 15 years after the GE90 entry into service, I remember a GE boast that no GE90 (carbon composite) fan blades had needed to be scrapped due to damage (birdstrike, FOD, etc. - now that was roughly another 15 years ago, so is probably no longer true, but it shows just how robust the carbon composite blades are - far better than the more conventional titanium fan blades).
Not saying it wasn't somehow birdstrike related, just that is very unlikely (then again, all the other explanations I can come up with are also very unlikely
).
Using improper temp when calculating TO performance - after some near misses, Boeing added logic that cross-compares multiple total temp probes - aircraft TAT (I think the 787 uses a single, dual element probe for aircraft TAT, but stand to be corrected) and the temp measured by the engine inlet probes - and puts up a message if they disagree by more than a few degree tolerance - so very, very unlikely.
N1 power setting is somewhat less prone to measurement and power setting errors than EPR (N1 is a much simpler measurement than Rolls EPR) - although even with EPR, problems on both engines at the same time is almost unheard of.
The Auto Thrust (autothrottle) function 'falls asleep' at 60 knots - and doesn't unlock until one of several things happens - 250 knots, a set altitude AGL is exceeded (I'm thinking 3,000 ft. but the memory is fuzzy), thrust levers are moved more than a couple of degrees, or the mode select is changed (memory says that last one is inhibited below 400 ft. AGL). So an Auto Thrust malfunction is also extremely unlikely. Further, a premature thrust lever retard would not explain a RAT deployment.
TO does seem to be very late in the takeoff role - even with a big derate, you still must accelerate fast enough to reach V1 with enough runway to stop - so there is still considerable margin if both engines are operating normally. That makes me wonder if they had the correct TO power setting - but I'm at a loss to explain how they could have fouled that up with all the protections that the 787 puts on that.
If one engine did fail after V1, it's conceivable that they shut down the wrong engine - but since this happened literally seconds after takeoff, it begs the question why they would be in a big hurry to shut down the engine. Short of an engine fire, there is nothing about an engine failure that requires quick action to shut it down - no evidence of an engine fire, and even with an engine fire, you normally have minutes to take action - not seconds.
The one thing I keep thinking about is someone placing both fuel switches to cutoff immediately after TO. Yes, it's happened before (twice - 767s in the early 1980s), but the root causes of that mistake are understood and have been corrected. Hard to explain how it could happen (unless, God forbid, it was intentional).
Disclaimer: never worked the 787, so my detailed knowledge is a bit lacking.
First off, this is perplexing - especially if the RAT was deployed. There is no 'simple' explanation that I can come up with.
GEnx-1B engines have been exceptionally reliable, and the GE carbon composite fan blades are very robust and resistant to bird strike damage (about 15 years after the GE90 entry into service, I remember a GE boast that no GE90 (carbon composite) fan blades had needed to be scrapped due to damage (birdstrike, FOD, etc. - now that was roughly another 15 years ago, so is probably no longer true, but it shows just how robust the carbon composite blades are - far better than the more conventional titanium fan blades).
Not saying it wasn't somehow birdstrike related, just that is very unlikely (then again, all the other explanations I can come up with are also very unlikely
).
Using improper temp when calculating TO performance - after some near misses, Boeing added logic that cross-compares multiple total temp probes - aircraft TAT (I think the 787 uses a single, dual element probe for aircraft TAT, but stand to be corrected) and the temp measured by the engine inlet probes - and puts up a message if they disagree by more than a few degree tolerance - so very, very unlikely.
N1 power setting is somewhat less prone to measurement and power setting errors than EPR (N1 is a much simpler measurement than Rolls EPR) - although even with EPR, problems on both engines at the same time is almost unheard of.
The Auto Thrust (autothrottle) function 'falls asleep' at 60 knots - and doesn't unlock until one of several things happens - 250 knots, a set altitude AGL is exceeded (I'm thinking 3,000 ft. but the memory is fuzzy), thrust levers are moved more than a couple of degrees, or the mode select is changed (memory says that last one is inhibited below 400 ft. AGL). So an Auto Thrust malfunction is also extremely unlikely. Further, a premature thrust lever retard would not explain a RAT deployment.
TO does seem to be very late in the takeoff role - even with a big derate, you still must accelerate fast enough to reach V1 with enough runway to stop - so there is still considerable margin if both engines are operating normally. That makes me wonder if they had the correct TO power setting - but I'm at a loss to explain how they could have fouled that up with all the protections that the 787 puts on that.
If one engine did fail after V1, it's conceivable that they shut down the wrong engine - but since this happened literally seconds after takeoff, it begs the question why they would be in a big hurry to shut down the engine. Short of an engine fire, there is nothing about an engine failure that requires quick action to shut it down - no evidence of an engine fire, and even with an engine fire, you normally have minutes to take action - not seconds.
The one thing I keep thinking about is someone placing both fuel switches to cutoff immediately after TO. Yes, it's happened before (twice - 767s in the early 1980s), but the root causes of that mistake are understood and have been corrected. Hard to explain how it could happen (unless, God forbid, it was intentional).
Very hot day, so far past breakpoint, N1 Max sensitive to TAT. Any TAT or DT latching (can't recall if) would be cleared - if at 400 ft AGL, which may not have been attained here.
June 13, 2025, 03:27:00 GMT
permalink Post: 11899954
Also, I'm not sure exactly what you mean by "just off the runway after V1". I think V1 was probably some ways back.
June 13, 2025, 05:11:00 GMT
permalink Post: 11900006
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
This is a transport category aircraft. It will happily climb on one engine to a safe altitude where procedures are followed.
There is zero evidence of any engine "failures" or shutdowns by the crew.
However the gear is still down at around 500' agl.
June 13, 2025, 09:30:00 GMT
permalink Post: 11900245
I'm sorry but pilots are taught to recognise lack of acceleration during takeoff. They're also taught about cross checking FMC entries during setup. How are they taught? By me and many others.
Even if the pilots had the wrong FMC performance, it would be noticed in the before takeoff cxl.
Even if the pilots had the wrong FMC performance, it would be noticed in the before takeoff cxl.
I often contemplate when I rattle down the runway with 375 metric tons if I really hit V1 at the right place of the concrete strip. Although I learned how it feels when you stop with this weight at this very moment (engine failure with MTOM).
June 13, 2025, 10:11:00 GMT
permalink Post: 11900287
So what is known at the moment?
- The flight crew consisted of an experienced Captain and a First Officer with a little more than 1000 hours. Whether or not this flight was a training event appears not yet determined.
- The aircraft departed from Ahmedabad, using full length of the runway, lifting off at an appropriate distance from the departure end and reaching an altitude of less than 1000ft before descending again to an impact. It therefore got out of ground effect. Also, the power selected for takeoff was sufficient to get the aircraft airborne within the constraints of the field.
- The landing gear was left down much longer than usual and remained so for the whole duration of the flight.
- Flaps appear to have been extended normally to a setting not triggering any pre-takeoff configuration warning. On the 787, extended TE flaps are not as obviously visible as on other types, especially with low quality pictures, but a gap between the flaps and the wing proper was visible, showing a glimpse of the engine nacelle through it.
- Whether or not the RAT was out appears not entirely clear, although there are strong indicators of it being deployed. If this is confirmed, this seems to point to a major engine or electric issue.
- Engine noise is surprisingly low on the available videos, either drowned out by environnmental noise (the 787 is not a noisy bird) or due to lack of power produced.
- Descent was at a very high AOA and appears not intentional. The crew did not decide to push the nose down.
- The aircraft appears to have been structurally intact with nothing issuing from it. No debris, smoke, fumes or liquids were in trail, no parts were observed to have been lost or dropped.
- There seems to have been a mayday call from the aircraft, possibly indicating power issues.
The crew seems to have found no reason to abort the takeoff before V1. Whatever befell them must have struck past that speed and given them cause not to retract the landing gear. Whether the lever was not moved or the systems did not react to it is not determined yet.
The aircraft had enough energy to climb to about 600, in any case less than 1000ft altitude. Ahmedabad seems not to call for a specific NADP, but whether it was NADP1, 2, A or B that was flown, it is fairly safe to assume that its normal regime would have been takeoff power and takeoff flap settings at that time.
Multiple other aircraft departed from or arrived at Ahmedabad before the accident, of which at least one must in all probability have taken onboard the fuel from the local bowsers in substantial amounts and used it without troubles, or else there would have been other flights in trouble due to this.
I am awaiting the preliminary report from the authorities and the readout of the data recorders with much interest.
- The flight crew consisted of an experienced Captain and a First Officer with a little more than 1000 hours. Whether or not this flight was a training event appears not yet determined.
- The aircraft departed from Ahmedabad, using full length of the runway, lifting off at an appropriate distance from the departure end and reaching an altitude of less than 1000ft before descending again to an impact. It therefore got out of ground effect. Also, the power selected for takeoff was sufficient to get the aircraft airborne within the constraints of the field.
- The landing gear was left down much longer than usual and remained so for the whole duration of the flight.
- Flaps appear to have been extended normally to a setting not triggering any pre-takeoff configuration warning. On the 787, extended TE flaps are not as obviously visible as on other types, especially with low quality pictures, but a gap between the flaps and the wing proper was visible, showing a glimpse of the engine nacelle through it.
- Whether or not the RAT was out appears not entirely clear, although there are strong indicators of it being deployed. If this is confirmed, this seems to point to a major engine or electric issue.
- Engine noise is surprisingly low on the available videos, either drowned out by environnmental noise (the 787 is not a noisy bird) or due to lack of power produced.
- Descent was at a very high AOA and appears not intentional. The crew did not decide to push the nose down.
- The aircraft appears to have been structurally intact with nothing issuing from it. No debris, smoke, fumes or liquids were in trail, no parts were observed to have been lost or dropped.
- There seems to have been a mayday call from the aircraft, possibly indicating power issues.
The crew seems to have found no reason to abort the takeoff before V1. Whatever befell them must have struck past that speed and given them cause not to retract the landing gear. Whether the lever was not moved or the systems did not react to it is not determined yet.
The aircraft had enough energy to climb to about 600, in any case less than 1000ft altitude. Ahmedabad seems not to call for a specific NADP, but whether it was NADP1, 2, A or B that was flown, it is fairly safe to assume that its normal regime would have been takeoff power and takeoff flap settings at that time.
Multiple other aircraft departed from or arrived at Ahmedabad before the accident, of which at least one must in all probability have taken onboard the fuel from the local bowsers in substantial amounts and used it without troubles, or else there would have been other flights in trouble due to this.
I am awaiting the preliminary report from the authorities and the readout of the data recorders with much interest.
Last edited by Tu.114; 13th June 2025 at 10:32 .
June 13, 2025, 12:16:00 GMT
permalink Post: 11900432
I said below 100 feet, it didn't get higher than that. Are there any memory items, or indeed emergency checklists, to complete between V1 and 400 feet?
June 13, 2025, 12:23:00 GMT
permalink Post: 11900447
Originally Posted by
A4
But selection of TOGA would result in near instant max thrust. How much extra above what they already had at 37\xb0C OAT I don\x92t know\x85. but if they had derated too much due possible data input error, then TOGA would mitigate with near immediate effect? No?
A4
A4
The power they selected for takeoff was sufficient to get them airborne. Whatever noise abatement protocol was chosen, the power will not be reduced before 1000ft AAL, so whatever N1/EPR (I do not know what indication the engines on the accident plane used) got them out of the runway was still selected.
If lack of power was an issue, this problem started after V1 and likely after liftoff. One working engine would have sufficed to get them out of the runway after V1 and to a relanding, this is a regulatory requirement. That the weight, temperature, air density, obstacle situation and so on allows for this will have been confirmed during the takeoff data calculation.
June 13, 2025, 12:24:00 GMT
permalink Post: 11900448
Originally Posted by
Chesty
Are there any memory items, or indeed emergency checklists, to complete between V1 and 400 feet?
