Posts by user "fdr" [Posts: 33 Total up-votes: 201 Pages: 2]

TE Flaps are extended, flap gaps between the wing and the flap element are observable. This is not an aberration of the spoiler position, you can see the nacelles through the gap, and that means the flap can not be in the retracted position.

An error of the TE flap deployed position, say between flaps 5 or 15 is not going to cause a stall event.

The flap has not been retracted instead of the gear.

Double engine failure... India. birds, always a latent threat. No rudder deflection, no aileron deflection, so it's not a SE problem, any engine issue is affecting both engines.

Pitch control and roll is not compromised in the video. The crew put out a mayday, not sounding like an electrical fault or distraction.

any funerals near by?

Incorrect TO thrust setting would not present in the video as recorded. Low thrust results in low acceleration, and extended distance to rotate. after rotate, low thrust results in low climb rate, and can result in the crew over pitching where the aircraft has obstructions that the crew have to avoid. the video appears to show the pitch increasing at a point where the aircraft is already unable to climb, not the other way round. An outside possibility.

For survivors, any from the aircraft will be a miracle, and mainly from the rear of the plane near door 3 area, if any. Plane is still striking tank traps at 70m/sec +, high ANU, it's not a high survivability event. Occupants in the buildings along the flight path will have a high fatality rate as well. This is going to be a high toll event in the aircraft and on the ground. Bad day at VAAH. RIP.

The video from the NE end of the runway, beside the RVR sensor shows a liftoff occurs abeam the closed high speed taxiway between C and D. Thats at 1250m to run to the DER. The first 10 seconds of flight is steady, and then the aircraft stops climbing and starts a gentle descent, and 5 seconds later the pitch starts to increase in 2 stages with impact around 20 seconds after liftoff. This is not the ADSB data, it is the video at the boundary on F/B.

The video take from the south end of the airport appears to show the RAT deployed.

The flight VAAH-EGLL is not a particularly heavy departure, the takeoff distance is not unreasonable for a twin jet, at under 7,000' from brakes release. I have limited developmental time only on the 787 before EIS, and I cannot recall any surprising latent threat in the performance of the aircraft for a premature flap retraction, and that certainly would not result in a RAT deployment. An accidental ATR low level off capture might get exciting for a few seconds, but it would not result in a RAT either.

The seat 11A pax survivor is remarkable.

This aircraft has got airborne well within the requirements of FAR 25 under which it was certified. It has over 1250m ahead of it passing around 35' based on the video from behind, so the FMC data was not incorrect, the thrust up until after TO was not incorrect, and the CG is not out of range, the time to rotate is within expected range, and the attitude at liftoff is not excessive, the plane is not heavier than expected. This is not Emirates, Tiger or SQ, it may have a resemblance to AFR out of Nigeria, or ANZ out of Raro, or UAL out of Hilo. Unlikely but there are similarities.

A low altitude in the MCP can become pretty interesting, as will a TAT probe failure to the ATR thrust limit. Both cases will have the thrust levers moving back rapidly. There is no obvious failure of the engines at this point save the question that the RAT may be deployed. A transient electrical fault tripping the logic for the RAT is hard to imagine, but that would possibly end up with an ATR fault and power coming back to idle. Fuel contamination is not impossible, but it is improbable, the engines would have been on their TO configuration from the engine start, and the taxi and turnaround takes enough time to flush the fuel lines, being longer than the selected tank sampling time that sits behind the SOPs. Boeing aircraft are easier for the crew to detect anomalous thrust commands compared to the Airbus, however, if the RAT is out... then more was happening.

The flaps are in the correct position, we are looking at a time critical failure for the crew, they appear to have around 10 seconds between onset and impact, and they have rotated the aircraft in the later stages, as any reasonable pilot would do, and that certainly does not indicate a crew initiated problem on the available information. Unlawful interference is unlikely, given the RT calls that have been made.

The IDGA AAIB is not known for rapid response, this event is of international importance, it appears that it is being treated as such by the authorities involved. The EAFRs on the 787 will tell all soon, and we need that information, this is a globally important aircraft type.



The Daily Telegraph has apparently put out a photo that is of the rear view of the aircraft, showing the TE flaps have a visible gap between the flap element and the wing, that is, the flaps are extended. If they were not, you get to see nothing. Int he gap, you can clearly see the fan exit of both engines.... ergo, the TE flaps are deployed. This same article then highlights this and exclaims that the flaps were retracted.

Is it safe to assume that the education standard of writers and editors of UK papers has been depleted somewhat?

Such comments are inflammatory to those that have lost family in this tragedy, and directly impugn the flight crew, and are factually, grossly wrong. This isn't just sloppy journalism, it is defamatory to those that cannot speak in their own defence. Sorry Mods, but someone needs to stand up for those that cannot against offensive drivel that passes for informed media commentary.

Here is a photo of the aircraft at the point that some numpties have stated the flaps are not employed. Apparently the authors should visit spec savers, or get a guide dog at least. At least, they get great blue coloured parking. In the same image, the RAT is observable.

The comments that are floated that some experts suggest that the crew may have not been able to get the gear up and may have retracted the flaps shows an utter lack of understanding of the certification basis of our aircraft. The flaps are out at a relevant TO flap extension setting for the conditions.

The same bastion of British broadsheets shows an image that is already on this thread, of a takeoff from mid field, while at the same time showing a still of the NE corner video near the RVR gauge east of the PAPI at the N end of the runway. One can only conclude that there is a dearth of good loo paper in the UK, and this standard of rigorous investigative reporting can be best applied to ones soft spots for personal hygiene. take 5 minutes out and do an triangulation from the point of observation, and surprise, the aircraft lifts off abeam the closed high speed taxiway. Not at the end of the runway, 1250 meters north of the DER. Taking ADSB data and not running a validation of it is mentally lazy and leads to hurtful assumptions that taking a slight amount of reasonable due care would have avoided.

rude letter follows...







https://www.telegraph.co.uk/news/202...a-plane-crash/


This is interesting enough without dealing with the media who show once again the mental acuity and sharp insight of a bowling ball.

On item 1, the TCMA issue should have been fixed, it does fit the sort of issue that occurred here. TDRACER can talk to that, and has done in 2019 and again in post 792. As to flap auto retraction, the B787 like all Boeings has a gated flap lever, and the flaps are only able to move independent of the lever by flap load relief. That would not have caused a loss of thrust, and in this case it is evident that the event is a thrust loss not a CL loss.

On item 2, the video shows no asymmetry at any time, so there is only a symmetric failure of the engines possible. Back on a B747 classic, you could chop all 4 engines at the same time with one hand, on a B737, also, not so much on a B777 or B787. I would doubt that anyone used two hands to cut the fuel at screen height. Note, there was a B744 that lost one engine in cruise when a clip board fell off the coaming. Didn't happen twice, and it only happened to one engine.


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Neila83 is correct, the gear tilt pre retraction is rear wheels low, and at the commencement of the selection of the retraction cycle (generally), the first thing that happens is the inboard MLG doors start to open below the wheel well and then the bogie is driven to front wheels low. (There is also an option that the inboard gear doors start to open early as a result of WOW sensing to improve the SSL climb limit). [my bad, for the B788 Capt Bloggs informs us the gear door sequence is after the tilt, not before, the B789 has the before tilt, the option for the door open at rotate is separate]

The inboard doors do not appear to have opened in this case, yet, the gear is forward wheels down. This appears to be out of sequence. TD may have better knowledge on the options that exist with the B788, but this is not looking good at this time.

There is enough in the way of anomalies here to end up with regulatory action, and airlines themselves should/will be starting to pore over their systems and decide if they are comfortable with the airworthiness of the aircraft at this moment. A latent single point of failure is not a comfortable place to be. Inhibiting TCMA might be a good interim option, that system could have been negated by having the ATR ARM switches....(Both)... ARM deferred to the before takeoff checks. The EAFR recovery should result in action within the next 24-48 hours. Boeing needs to be getting their tiger teams warmed up, they can ill afford to have a latent system fault discovered that is not immediately responded to, and the general corporate response of "blame the pilots" is not likely to win any future orders.

I think we are about to have some really busy days for the OEM.


Not sure that Neila83 is that far off the mark at all.

1. The video from the NE of the airport shows that the TO run was not excessive, the ADSB data is erroneous. That would suggest that the thrust set was reasonable
2. An altitude capture at the engagement of VNAV will result in the thrust coming back very rapidly. It has happened and will happen again. It doesn't need crew error in all cases, a failure of the MCP digitiser used to cause the same problem, despite the desired target being shown above the alt strip. It was one of the oddball cases where what is displayed is not necessarily what is being targeted. In such a case however, the ATR unless it has been turned off will still wake up again if it has been disconnected by the throttle instinctive disconnects, when a low airspeed has been detected.

The WDMs will be getting scrutinised up in Seattle at the very least.

Many thanks. It still is a concern that the tilt has occurred but no doors have opened.

Agree with most of your comments, but Lauda 004, the B763ER/PW4060 aircraft, no evidence was developed to indicate a G/A sensing fault. The report is available on line,

Lauda Air B767 Accident Report

Lauda 004 taught that the flight test of reverse had some assumptions that were not accurate. The reduction in lift from the flow interaction with the wing was not recognised before Lauda 004, and before that was discovered, there were a lot of flight departments that were rather judgemental of the event due to their own ignorance. Just because our sims say it is so doesn't mean that the aircraft agrees.

Are you thinking of a B787 which does not have FBW? Admittedly C* is not quite as tidy as C*U when it is working normally, but B777 and B787 systems do a darn good job of removing thrust-pitch couples (well, adequate).

If you are referring to loss of all boost pumps, am not aware of any engine that will not continue to run with a suction feed to the main boost pumps at low altitudes. At high altitudes, there is a chance of cavitation of the main pumps but only at very high powers, and generally not at sea level.

TD, in this case, the RT call suggests we are a grand total of 1 choice, and that goes to a fair likelihood that a fleet wide grounding is in the offing. Adding system complexity dependent on sensor reliability has bitten us all in the past and will do again, and I have a bad feeling that is where we are at with this. The SSA guys will be working overtime, but this has had the hall marks of being a bad sensor/system event from the outset. Am laying bets that there will be a fleet wide grounding in the next 3-4 days, if not sooner. Inadvertent GA thrust after landing has occurred before, (had it on a B744 myself), and it is curious but straightforward to handle.

Yes.

PM on way.

The video is suitably clear to show that one engine DID NOT lose thrust before the other engine. The yaw rate authority in the FCS is going to input rudder immediately a failure of an engine occurs, (the 787 asymmetry architecture is quite different to the TAC on the B777) and so a rudder deflection would be evident. The video from the rear is ideally positioned to show a rudder deflection, and one would have been required, or a roll would have eventuated. Being FBW, the ailerons and asymmetric roll spoilers would be actuated to maintain the aircrafts attitude without any input by the crew if there is no roll rate command given by the control column (this is slightly different to the B777 as well).

The Thrust Control Malfunction Accommodation TCMA shuts down an engine when an idle asymmetry is detected . On the ground . With thrust levers at idle . The engine in question triggers the condition when it is above idle and not decelerating normally . That is multiple failure conditions that need to have occurred in the system to allow that to occur. It is nearly as wild a circumstance as the QFA 072 suspected cosmic bit flip, except that these are supposed to be independent systems. This does have the authority when the conditions exist to turn off the noise. That is the only reason it is a subject of interest.

The Thrust Asymmetry Protection gives a limited authority to reduce thrust on the surviving engine to maintain control. It would not trigger the conditions that the engines have gone silent, and hydraulics/electrics have been mussed up. That puts a spotlight on what has to go wrong on TCMA to get it to trigger outside of the conditions that it is intended to.

No yaw input, no roll input, no asymmetry. That leaves either both engines running at normal TO thrust or both having a simultaneous bad day out. Giving car keys to HAL 9000 can have some issues, and cosmic radiation is around a lot.

What pilot action is positively ruled in and what pilot action is positively ruled out at this stage?

From the comfort of my couch, I would contend that this crew have had a condition that was extraordinary (in the full meaning of the word) and have acted in a timely and correct manner. There is nothing in the flight path other than the fact the aircraft isn't at a gate in London that indicates otherwise. The fact the aircraft is not sitting in London does not have any characteristic event in the available information to conclude other than through the general assumption that pilots always cause problems, and having done nearly half a century in flight safety investigation in the military and airlines, I would contend that on balance flight crew save aircraft far more often than they cause losses. "It takes a computer to really stuff up something..."


Not at all, the system including the OEM and Regulator have duty of care obligations that they tend to take seriously, mores than the public gives them credit for normally. In this case, the investigators have data that will shortly be sufficient to determine the immediate actions that would be necessary to mitigate risks to the public. My own opinion is that action is shortly coming, it doesn't need the EAFR, and it will cause its own political fall out.

The B735 crash event was evident from the first access to the ADSB data. The kinematics told the story, which is usually the case. In this case, the flight path is sufficiently clear to be of concern. Specifically, this event from a human-in-the-loop is a binary outcome. There is zero grey areas in the involvement of the flight crew, and I contend that there is no reason to consider their actions as being anything other than exemplary. If the area mic shows otherwise, I will amend my position, but right now, I have greater concerns with the continued operation of the B787. This event is an either/or, a binary event, like Kev Sullivan's QF072, and I fear we are seeing a similar family of causation. Kev's a former squadron mate and friend from the airline, and the pax were fortunate to have him on board that day.

The untidy truth related to this event is that either causation will have ramifications to the industry for the foreseeable future; there is nothing trivial about this event from a systems viewpoint, apart from the devastating loss to every person concerned in the tragedy. Not than many accidents are so consequential in their impact, this will be one of those.

Water ingress into the E/E bay is a serious issue. The B744 had this issue in the past causing serious problems, one of which was fortunate to not lead to a loss of the aircraft, on a B744F. The B744 pax aircraft had a number of water problems related to the toilets and the galley. The forward galley on the B742/3s had many issues.

Any large aircraft going through maintenance is interesting to observe the extent of corrosion that occurs near toilets and galleys, and from water lines.

The B777 was not immune to this either. The potable water tank failing caused one of our aircraft to have 6.5 tons of ice accumulating in the underfloor area of the aft cargo hold, which we detected on a preflight walk around as a series of water streams from the drain holes in one area of the aircraft. This was an interesting item for CG, a note on weight, but only affected the electrical services related to the aft cargo systems.

Water accumulations on the B744 came to light at rotate, and took out a lot of electrical services.

My suspicion is some cause such as this will come to light shortly.

The water leak issues with the B787 go back to in service reports in 2014 and before, considered an unsafe condition in 2016, and were covered by AD 2016-14-04. This latest AD is curious as it stems from an administrative oversight in the drawings of the aircraft, that arose on aircraft manufactured from 2018 onwards. 2025-09-12 stands alone related to missing sealant, following the drawing oversight in production. It did not affect all aircraft. The earlier AD, 2016-14-04 was related to water line coupling issues, and is in Service Bulletin B787-81205-SB380009-00 WATER/WASTE - Water System- Potable Water System - Couplings Replacement. It notes on page 21 of 229 the reason for the work

The latest AD and the earlier AD highlight that problems can occur, and have done so in the past. Both of the E/E bays contain stuff that is nice to keep dry and operating, and prior events have shown that multiple system failures can and have occurred when a flood is added to all the black boxes sitting innocently on their racks.

The ADs are not necessarily directly related to the specific cause, they highlight the potential for water damage and that bad stuff happens. In two cases I investigated, the event occurred at rotate. Both were B744's one pax, one F.

Compound, unrelated system failures at rotate? Single cause? Water in the E/E bay.

The amount of flooding that occurs in the toilet cubicles is unfortunate, apparently towels still fit well into toilet bowls, signs are disregarded etc. Coffee grounds block galley drains with monotonous regularity, the planes are only as good as we care for them, and passengers seem to have odd ways of treating the conveniences.

I will wager that this is absolute nonsense. The effect of pulling the power levers back to idle at rotate would be readily countered by pushing them back up again. The engines are still delivering thrust, it is a function of N1, not the lever. The lever commands where the thrust level will end up, the N1 gives the thrust output. The acceleration/thrust characteristics of these engines is not like a J52 or JT3D etc.

The proposition that is floated is that the pilot does not pull back on the control column, which he is holding onto with both hands as his seat slides backwards like a caricature of a bad Cessna 180 seat rail, that is plainly obvious from the pitch attitude of the aircraft, yet grabs lustily a double handful of thrust levers and holds onto those until meeting Ganesh in the next life?

Greek papers appear to be as rigorous and incisive in their cognition as the Daily Telegraph. Golly.

Seats: electric.
RAT deployment... presumably the hapless pilot doesn't grab the control column, or the thrust levers, just grabs both fuel control switches instead????

Do any reporters bother to read what they write?

Adding to your response TD, there is no time in this event where a high AOA arose prior to the final moments, around 13 seconds after the problem has occurred. AOA, intake separation is not a factor.

Going back to your prior comments on FADEC and TCMA; these are independent systems to each engine, however the event indicates a symmetric loss, and the potential of water ingress from a failed E/E sealing from the main cabin services remains a single causation that could result in multiple failures at the same moment. The last time I assessed issues in the E/E bay related to unauthorised inflight access to the fwd E/E of a B777 it was sobering how many irreversible conditions could arise. The B744 water inundation cases I was involved in were both on TO, the QF event was during deceleration. We are looking at vectors that come from outside of the normal assumptions in the SSA's, water fits that bill.

Insufficient data. There is cooling in the bay and that can be affected by aircon problems. High humidity and temp can lead to moisture in the area, however, the events I had involvement with were massive amounts of water from various sources. One was a failure from the toilet system, and the other was related to cargo loaded on the main deck via the NCD, and that had pallets that had turned into swimming pools that made a fashion statement when rotated. The QF event was similar, water accumulated in a damaged barrier.

Yes.
1250m from the end of the runway, between high speed C and D, adjacent to the closed high speed.
There is nothing unusual with the rate of acceleration that is observable ninth video. You can work that out using google earth and the Indian AIP and/or state airport charts. The weight of the plane can be estimated by the flight time and pax load and an allowance for cargo. The simplified TO performance is in the inflight performance section of the FCOM, which you may find a copy on line.
The aircrafts rotation has no obvious issues, until a few seconds after achieving an attitude that is consistent with the V2+15-25 range, at which point the ROC visibly starts to decay.

On item 1, the TCMA issue should have been fixed, it does fit the sort of issue that occurred here. TDRACER can talk to that, and has done in 2019 and again in post 792. As to flap auto retraction, the B787 like all Boeings has a gated flap lever, and the flaps are only able to move independent of the lever by flap load relief. That would not have caused a loss of thrust, and in this case it is evident that the event is a thrust loss not a CL loss.

On item 2, the video shows no asymmetry at any time, so there is only a symmetric failure of the engines possible. Back on a B747 classic, you could chop all 4 engines at the same time with one hand, on a B737, also, not so much on a B777 or B787. I would doubt that anyone used two hands to cut the fuel at screen height. Note, there was a B744 that lost one engine in cruise when a clip board fell off the coaming. Didn't happen twice, and it only happened to one engine.


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Neila83 is correct, the gear tilt pre retraction is rear wheels low, and at the commencement of the selection of the retraction cycle (generally), the first thing that happens is the inboard MLG doors start to open below the wheel well and then the bogie is driven to front wheels low. (There is also an option that the inboard gear doors start to open early as a result of WOW sensing to improve the SSL climb limit). [my bad, for the B788 Capt Bloggs informs us the gear door sequence is after the tilt, not before, the B789 has the before tilt, the option for the door open at rotate is separate]

The inboard doors do not appear to have opened in this case, yet, the gear is forward wheels down. This appears to be out of sequence. TD may have better knowledge on the options that exist with the B788, but this is not looking good at this time.

There is enough in the way of anomalies here to end up with regulatory action, and airlines themselves should/will be starting to pore over their systems and decide if they are comfortable with the airworthiness of the aircraft at this moment. A latent single point of failure is not a comfortable place to be. Inhibiting TCMA might be a good interim option, that system could have been negated by having the ATR ARM switches....(Both)... ARM deferred to the before takeoff checks. The EAFR recovery should result in action within the next 24-48 hours. Boeing needs to be getting their tiger teams warmed up, they can ill afford to have a latent system fault discovered that is not immediately responded to, and the general corporate response of "blame the pilots" is not likely to win any future orders.

I think we are about to have some really busy days for the OEM.


Not sure that Neila83 is that far off the mark at all.