12.06.2025| VT-ANB | Air India | AI171 | B787-8 Dreamliner | Ahmedabad VAAH | Absturz nach Start

[Johnny]

Dass die Schalter mechanisch umgelegt wurden, steht ja bereits fest. Die Frage ist nur noch, ob absichtlich oder nicht absichtlich und durch wen. Softwarefehler ist bereits ausgeschlossen.

[Manfred J.]

Nicht ganz uninteressant, oder?!

 

https://avherald.com/h?article=52b0a800&opt=0

 

 

[Tomi]

Die iP-Adresse ist blockiert. Nur bei mir?

[FalconJockey]

Bei mir klappt es. Ist ein langer Text.

 

[Autofahrer]

vor 11 Stunden schrieb Manfred J.:

Nicht ganz uninteressant, oder?!

 

https://avherald.com/h?article=52b0a800&opt=0

 

 

 

Man muss sich zwangsläufig fragen, warum ist der Zwischenbericht so formuliert, wie er ist. Die fehlenden Zeitstempel könnten auch daher herrühren, damit eine suizidale Absicht nicht direkt bestätigt wird.

 

Grundlegend wissen die Ermittler aber längst viel mehr. Die wissen, ob der Schubverlust vor oder nach dem Cut off stattgefunden hat. Da gibt es auch nichts zu vertuschen, zumal diverse Behörden involviert sind. Die Veröffentlichung vom "Warum" und "hab ich nicht" wäre in diesem Zusammenhang irreführend und stümperhaft. Da hätte zwischenzeitlich längst ein Leak stattgefunden, wenn es denn nicht den Tatsachen entspricht, und/oder irreführend wäre. 

Stattdessen wird von der fliegenden Zunft ins Detail hinterfragt um irgendwie die Piloten zu entlasten, was man zwar auch verstehen kann. 

 

Weiters sind die 787 in der Luft. Man kann es zwar als "unwahrscheinlichen Zwischenfall" deklarieren. Jedoch glaub ich nicht, dass man ein Muster in der Luft lässt, welches aufgrund systembedingtem Ausfall in der Steigphase den Schub verliert. Gäbe es eine technische Ursache analog BA38, die 787 würden sich die Räder in den Boden stehen. 

 

Letztendlich werden wir es im Abschlussbericht erfahren, was und wie sich zugetragen hat.

 

 

Grüsse

 

 

[cloudcruiser228]

Ich habe über chatGPT eine deutschsprachige Inhaltsangabe erstellen lassen:

 

Am 12. Juni 2025 stürzte eine Boeing 787-8 der Air India (VT-ANB) kurz nach dem Start in Ahmedabad ab. In der vorläufigen Untersuchung finden sich widersprüchliche Hypothesen: Eine Gruppe vermutet vorsätzliche Handlung eines Piloten, andere sprechen von technischem Versagen oder versehentlichem Umlegen der Kraftstoffschalter.

Der Autor vertritt die Auffassung, dass beide Triebwerke bereits vor dem Umlegen der Schalter begannen, auf Leerlauf abzubremsen. Die Piloten hätten daher korrekt gemäß Checkliste („Dual Engine Failure“) gehandelt: Kraftstoffschalter für wenige Sekunden auf „CUTOFF“, danach zurück auf „RUN“, um die Engine Electronic Controls (EEC) zurückzusetzen und eine automatische Wiederzündung zu ermöglichen. Dies erkläre auch den Hörfunkhinweis im Cockpit („Why did you cutoff?“).

Sechs Beobachtungen stützen diese Meinung:

1. Kamerabilder zeigen die Ram Air Turbine (RAT) bereits bei etwa 75 Fuß Höhe auszufahren – vor dem dokumentierten Schalterumlegen.

2. Die Höchstgeschwindigkeit von 180 KIAS wurde um 08:08:42 UTC erreicht und fiel sofort ab, was auf schwindenden Schub deutet.

3. Blinken von Positionslichtern und ADS-B-Daten endeten zugleich, was auf frühen Elektrik­ausfall durch Motordrehzahlschwund hindeutet.

4. Cockpit-Aufzeichnungen (CVR) und Flugdaten­schreiber (FDR) werden nur unvollständig wiedergegeben, sodass unklar bleibt, wann Triebwerks­parameter abfielen.

5. ADS-B-Daten bestätigen den Sinkflug bereits bei 75 Fuß kurz vor der Pisten­schwelle.

6. Die Fahrwerkshebel blieben unten, obwohl bei Standardverfahren nach positiver Steigrate „Gear up“ erfolgt wäre – ein Hinweis, dass die Piloten frühzeitig Alarm schlugen.

Der Autor betont, dass ein vorsätzliches Umlegen der Schalter ohne vorheriges Ausfallen der Triebwerke unwahrscheinlich ist. Vielmehr sei das Manöver Teil des „CT­­RL-ALT-DEL“ für die EEC, um das Überdrehzahl-Relight bei dualem Triebwerks­ausfall zu ermöglichen. Die eigentliche Ursache des Triebwerks­ausfalls bleibt offen: Mögliche Defekte an Leiterplatten (MN4), ungewöhnliche Eisblockaden oder andere seltene Fehler müssen noch untersucht werden.

Bis zur abschließenden Analyse aller technischen Daten – insbesondere der vollständigen CVR- und FDR-Informationen – seien Schuldzuweisungen gegen die Cockpitbesatzung verfrüht.

Bearbeitet Freitag um 07:41 von cloudcruiser228

[Frank Holly Lake]

vor 12 Stunden schrieb Tomi:

Die iP-Adresse ist blockiert. Nur bei mir?

Gestern in Prag und genau so geo geblockt.

Hier der Asuzug aus AVH

 

Editorial on India B788 at Ahmedabad on Jun 12th 2025, lost height shortly after takeoff, no thrust reported

By Simon Hradecky, created Thursday, Jul 31st 2025 17:35Z, last updated Thursday, Jul 31st 2025 17:35Z There is a war of beliefs hitting the world following the crash of Air India's Boeing 787-8 VT-ANB in Ahmedabad on Jun 12th 2025, see our actual coverage at Crash: India B788 at Ahmedabad on Jun 12th 2025, lost height shortly after takeoff, no thrust reported. One large part of people believe especially following the release of the preliminary report, it had been a deliberate act to crash the aircraft by one of the pilots and based on some unconfirmed and premature newspaper report even point towards the Captain of the flight, another part believe it might have been an accidental flip of the fuel switches, others believe the crash might have been caused by a technical failure. Let me summarize my own opinion on this preliminary report and provide my reasons: I believe, that the fuel switches have been moved indeed into CUTOFF and 10 seconds later back to RUN by one of the pilots. However, not to crash the aircraft but in an attempt to RESCUE the aircraft in accordance with the memory checklist items for dual engine failure. I believe, the engine run downs began prior to the fuel switch signal transitioning to CUTOFF and the crew reacted correctly according to the memory items for dual engine failure, which require the crew to move both fuel switches to CUTOFF, wait, then bring them back to RUN in order to reset both Engine Electronic Controls (EEC) and also force a switch to the other channel of each EEC in order to relight at least one if not both engines. Now, how do I get to this opinion? Let me first summarize some of the relevant Boeing documentation, then provide my observations. Boeing 787 Manuals regarding dual engine failure The Boeing Manuals state: "Dual engine failure is a situation that demands prompt action regardless of altitude or airspeed. Accomplish memory items and establish the appropriate airspeed to immediately attempt a windmill restart. There is a higher probability that a windmill start will succeed if the restart attempt is made as soon as possible (or immediately after recognizing an engine failure) to take advantage of high engine RPM." and further: "Cycling both fuel control switches is used during a dual engine failure to reset both EECs." The first four steps of the according checklist are: 1) FUEL CONTROL switches (both): CUTOFF, then RUN 2) RAM AIR TURBINE switch: Push and hold for 1 second 3) Set airspeed above 270 knots. 4) APU selector (if APU available): START, then ON This therefore suggests, that the immediate reaction to a dual engine failure would be to put the fuel control switches into CUTOFF and back to RUN as quickly as possible. Also, manually deploy the RAT, maintain at least 270 KIAS and bring the APU online if available. The case of NH-985 of Jan 17th 2019 has shown however, that following the checklists was not successful. The Boeing 787-8 had landed safely, when after touch down both engines rolled down. Despite the crew exactly following the checklists, the engines could not be restarted. Subsequent simulator tests showed, that rapid cycling (quick transition from CUTOFF to RUN) would very often not be successful, however, relight (reset of the EEC) would have been possible if the crew had waited at least 5, better 10 seconds to return the fuel switch to RUN after bringing the fuel switch to CUTOFF in order to ensure, that the EEC does get reset – this timing window was found essential for relighting engines. It is further stated, that it is possible to repeat the sequence if the engine(s) do not relight, if repeat attempts are to be made, wait 10 seconds between CUTOFF and RUN. The manuals do not state, how long it will take for an engine to run down in case of a failure or a fuel cutoff, however, experience is that unless a catastrophic engine failure occurs (seizing the engine) the run down will take around 2-3 seconds. These engines were about to recover according to the preliminary report, hence no catastrophic failure. In 2020 the FAA issued Guidelines for aircraft certification with respect to “In-Flight All-Engines-Out Restart Guidance”. The Test Scenario, that would match AI-171, is “Scenario A: High Power and Low Altitude”, reads: The applicant should demonstrate that it is possible to restore engine power immediately following an all-engines-out scenario, during take-off and the initial climb-out. The applicant should use any method available (refer to Section 6.1). The intent of this test is to demonstrate an acceptable level of safety by minimizing the time exposure of unrecoverable total thrust loss in the event of a “common cause” total thrust loss (i.e., flightcrew error, unrecoverable compressor stall, etc.) at a combination of high engine power, low airplane speed and low altitude. While flightcrew errors in service have led to this scenario, it is not the only concern. There is still potential for a total thrust loss from an engine stall or environmental encounter where auto-restart features are insufficient and the engines are recoverable through flightcrew action. The airplane should have this capability following an all-engines power loss that occurs at a low airspeed that is operationally representative of the end of the take-off and lower end of the climb portion of flight. This speed is typically the initial climb-out airspeed and for most large transport airplanes is typically V2 + 10 knots. For the purposes of this test scenario, the V2 is defined as the normally scheduled balanced field length V2 for an airplane taking off using the greatest appropriate flap setting. If an applicant proposes a higher airspeed, then the applicant should justify a higher airspeed is representative of the end of the take-off and lower end of the climb portion of flight for the specific airplane under evaluation. The applicant should also justify why it is acceptable not to demonstrate capability for their airplane between the proposed higher airspeed and at V2 + 10 knots. This higher airspeed should not be more than VFTO. The airplane and engine systems supporting engine start should not preclude restart capability during these conditions (e.g., the engine control should not wait for the engine to spool down to idle before allowing restart or otherwise intentionally delay the restart sequence). The FAA further down writes concerning allowable altitude loss however for Scenario A: Applicant proposed critical condition based on shutdown, typically 1500 feet. This seems to suggest that the certification criteria, although mentioning this scenario, do not really take a dual engine failure immediately at or after lift off into account. Boeing 787 Manuals regarding deployment of RAM Air Turbine (RAT) The manuals state with respect to RAT Extension: The RAT (Ram Air Turbine) deploys into the airstream by a spring-loaded actuator. The RAT (Ram Air Turbine) can deploy manually with a flight compartment switch or automatically when commanded by the HYDIF (Hydraulic Interface Function) or the BPCU (Bus Power Control Unit). The signal for RAT (Ram Air Turbine) deployment goes to two solenoids on the RAT (Ram Air Turbine). One of the two solenoids is necessary to deploy the RAT (Ram Air Turbine). The solenoids release a set of locking pawls in the deploy actuator. This lets the spring extend and force the turbine into the airstream. The HYDIF (Hydraulic Interface Function) logic prevents accidental automatic deployment on the ground. The RAT (Ram Air Turbine) door is mechanically linked to the RAT (Ram Air Turbine). When the RAT (Ram Air Turbine) deploys, the door opens. The RAT (Ram Air Turbine) deploys and supplies full rated hydraulic power in 6 seconds maximum and electrical power in 10 seconds maximum from the command. These conditions cause the RAT (Ram Air Turbine) to deploy automatically in flight: - Loss of all engines - Both engines are at less than minimum idle RPM (Revolutions Per Minute) - Loss of all hydraulic power – left, right, and center systems detect low pressure - Loss of all electrical power - BPCU (Bus Power Control Unit) detects loss of power to C1 and C2 TRU (Transformer Rectifier Unit)s - On approach, loss of all four EMP (Electric Motor Pump) hydraulic pressures and loss of either the left or right flight controls ACE (Actuator Control Electronics) - Rotor burst on takeoff that causes loss of both PECS (Power Electronics Cooling System) primary cooling loops. The RAT (Ram Air Turbine) is retracted on the ground by maintenance action. The Manual further states, that the RAT will be fully extended into the airstream two seconds after the signal to deploy. Given the time 08:08:47Z for hydraulic power available from the RAT as stated in the preliminary report, this means deployment was initiated a maximum of 6 seconds earlier, hence at the earliest at 08:08:41Z. Given the low speed of the aircraft at that time, where the RAT is still slow to spin up near the lower boundary of its operating envelope , it is likely that the RAT needed the maximum time. The preliminary report further states, that the aircraft reached its maximum speed of 180 KIAS at 08:08:42Z, 5 seconds prior to the RAT providing hydraulic power. First Observation Let me start with reader "Captain Crunch"'s reader comment of Jul 13th 2025 at 14:13Z: Now that we finally have a good pic of the doomed bird at the departure end, I want to draw your attention to a few things in the Prelim Report: 1. Do you see that red and white com tower with the little white shack to the left with a tree on it? That's the Indian Air Force Ramp, where the RAT is first filmed. 2. Do you see the building behind AI171? That's the New Passenger Terminal. 3. If you use sat shots to line up those two things, it appears to me AI171 is already 75 feet AGL approaching what looks like to me to be the Fixed Distance Runway Marker for opposite Rwy 05. 4 Doesn't the RAT take a while to deploy? after ALL NORMAL AC POWER is lost, (FCOM is so abbreviated, it may not say that, but 3rd party MTC courses do.) Doesn't this mean the engines quit on the runway? Since they have to wind down below idle and RAT takes 7 secs? after that to deploy and spin up?? So, just based on this picture Figure 15 on page 14 of the preliminary report, which unfortunately does not carry any time stamp, we have evidence that at approximately 75 feet AGL the RAT was already extended, at a time between 08:08:39z (liftoff/ground-air transition according to preliminary report) and 08:08:42z. According to the last ADS-B transmission the aircraft was 107 meters before the runway end at about 75 AGL and 174 knots over ground, the picture shows the aircraft more than 107 meters before the runway end, (it would require specialist analysis of the picture to compute the actual distance), however the aircraft appears almost over the fixed distance markers runway 05, hence almost 300 meters before the runway end with the RAT already fully extended, hence the RAT began to extend two seconds before the photo was taken. The preliminary report states that the RAT delivered hydraulic power at 08:08:47z. The Boeing Manual states, the RAT needs a maximum time of 6 seconds from the signal to deploy until hydraulic power becomes available, but also states that the time from receiving the signal to deploy the RAT needs two seconds to be fully extended and the propeller starting to spin up. At the same time, at a maximum speed of 180 KIAS the RAT is very close to its lower operational limits rather than its normal operating range near 270 KIAS, and will need the maximum time as specified. Hence the signal to deploy the RAT occurred at 08:08:41z or 08:08:42z. The preliminary report further states, that the first fuel CUTOFF signal came “immediately” after 08:08:42Z, the second fuel CUTOFF signal one second later. Hence the first cutoff occurred at 08:08:42Z or 08:08:43z, and the second at 08:08:43z or 08:08:44z. If the RAT thus deployed as a result to both fuel switches being brought into CUTOFF, the signal to deploy would occur at the earliest at 08:08:43z or even 08:08:44z. Hence hydraulic power would only be signalled by 08:08:49z or 08:08:50z. This suggests, that the RAT did not deploy in response to both fuel switches indicating CUTOFF. It is thus more likely the RAT deployed because both engines were already below idle, all electrics had been lost or all hydraulics had been lost at that point. The preliminary report does not mention any problem with the electrical or hydraulic systems. The engines need about 2-3 seconds to run down from takeoff thrust to idle, hence the problem causing the RAT to deploy began 2-3 seconds prior to the RAT deploy signal at 08:08:42z or 08:08:41z. Second Observation The preliminary report states: "The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec." At 08:08:42Z therefore the engines must already have been running down or the aircraft would increase its climb. Had they continued to deliver takeoff thrust until that point without increasing the climb at this stage, they would still deliver significant thrust for another second or two while rolling down and the aircraft would still accelerate and get faster than 180 KIAS or increase the climb rate. At 08:08:42Z the AAIB thus states, that the speed began to decay suggesting at the same time, that the engine thrust was either already less than needed to overcome the aircraft's drag, or the crew still increased the pitch and climb rate. According to the Boeing Manuals the best rate of climb would be between V2+15 and V2+25 knots. According to the preliminary report V2 was 162 KIAS, hence the crew would aim for a speed of 177 KIAS (V2+15) but would not reduce the speed (pull up) if the speed would be up to 187 KIAS, with 180 KIAS (V2+18) the speed remained in that range and there would be no pull up (increase of climb). Consequently, while the flight director initially commands a pitch of 8 degrees and after becoming airborne adjusts the pitch to maintain V2+15, it would also not command a pitch up if the speed is below V2+25. The report does not mention pitch, vertical speed and altitude/height at all, not at any time of the flight profile. However it would be necessary to determine, whether the speed began to decay at 08:08:42Z because of an increase in climb or loss of thrust. The report also does not state any of the engine parameters like N1, N2, EGT, fuel flow at any time of the flight profile. However it would also be essential to determine, when the roll down of the engines began. If the 180 KIAS became maximum because of loss of thrust while maintaining pitch (actually angle of attack), the total engine thrust would already have fallen to way below half of the thrust both engines would be able to deliver and to less than the thrust one engine would be able to deliver (and still permit the aircraft to safely climb out on single engine). Given the time of about 2-3 seconds the engines need to run down from Takeoff Thrust to idle the engine failure thus would have begun 2-3 seconds prior to 08:08:42z. As the aircraft became airborne at 08:08:39z according to the preliminary report, this would suggest the engine failure began still on the ground or immediately after becoming airborne, between 08:08:39z and 08:08:40z. Hence, if the crew did not further increase the pitch and climb rate at that point, at 08:08:42z the engines were already significantly running down. And only THEN, "immediately" after 08:08:42z, the fuel switch signals transitioned from RUN to CUTOFF. The airport CCTV Video recording the takeoff shows, that 16 seconds into the video the takeoff rotation begins, the aircraft becomes airborne at 19 seconds into the video and maintains that attitude for about a second, then a slight pitch down becomes visible at 20 seconds into the video suggesting the onset of trouble. No further pitch ups but rather further pitch downs are visible, hence it is unlikely that the crew increased the climb, but rather attempted to maintain their insufficient height as long as possible and to use their excess speed (from 180 KIAS down to stall speed) as long as possible, only then maintaining close to stall speed by pitching down trading the little height for speed. Hence the version that the engines were already running down at that point appears more plausible. With the time line provided in the preliminary report the aircraft became airborne at 08:08:39Z (or 19 seconds into the video), one second later the aircraft pitched slightly down, hence at 08:08:40z. This suggests that the begin of the engine roll down began at or before 08:08:40z, about 2-3 seconds prior to the fuel switches being brought into CUTOFF and about 1-2 seconds prior to the RAT beginning to deploy maximum 6 seconds before 08:08:47z, In other words: both engines running down preceded that fuel switch transition to CUTOFF. Third Observation In the takeoff videos available the aircraft has its navigation lights, landing lights and position strobes active during the takeoff run. Immediately after liftoff, within 1-2 seconds, the lights extinguish and the aft strobe stops as well indicating the electrical power supply had failed at that time. At the same time the last ADS-B position data was transmitted by the aircraft's transponder at 75 AGL about 107 meters short of the takeoff runway 23 end at 174 knots over ground and thus below 180 Knots Indicated Air Speed (which roughly coincides with the picture figure 15 on page 14 of the AAIB preliminary report showing the RAT already extended) and thus prior to the aircraft reaching 180 KIAS at 08:08:42z. This again suggests that the engines must have been already running down and must have reached flight idle or below for the electrical power supply to fail, thus again pointing towards the engines beginning to run down before the fuel switches transitioned to CUTOFF three seconds after lift off. Fourth observation The preliminary report is extremely selective with the sounds recorded on the CVR as well as with the FDR data. Not a single item of the CVR, except the two sentences mentioning a tiny snippet out of the pilot exchange, is contained in the report, although undoubtedly all these sounds as well as the entire communication between the pilots were already known when the preliminary report was written. As such, the report is grossly and unnecessarily incomplete and as result leaves a lot of questions unanswered and even raises additional questions. For example, it is entirely unclear when the crew detected the first problem, and how the crew reacted to the first indications of engine problems - the report rather seems to suggest unrealistically, that the only reaction of the crew was "Why did you cutoff"? No confusion, no "What's going on?", no "engines running down", ...? The CVR would most certainly record the sounds emitted by the fuel switches when being moved, and thus would be able to clarify whether the sounds and the signal transitions coincide or occur at different times. The CVR would also enable the analysis of the engine sounds. As such it is possible to determine what status the engines were in and at what speeds (RPMs) they were operating throughout the flight. Thus it is also possible to determine when the engines began to run down, and whether this was prior to the transition of the fuel switches signal to CUTOFF or after that signal. The FDR records engine data like N1, N2, EGT, Fuel Flow for both engines. A graph of these parameters would make it instantly clear when the engines began to run down. Therefore it would be instantly possible to determine, whether the beginning of the engine failures came before or after the fuel switches being put into CUTOFF. I would have expected that one month after the crash all these questions would already have been answered though not yet analysed and not the cause of this all clarified, but at least the question answered: did the engines begin to run down prior to the CUTOFF or only after - in a way that is in line with all the other indications presented in the preliminary report and matching the time lines mentioned. Fifth Observation According to ADS-B Data the last transmission from the aircraft was at 174 knots over ground (and thus even less than 174 KIAS), at 75 feet AGL still over the runway about 107 meters short of the runway end. This coincides with the picture figure 15 on page 14 of the preliminary report showing the aircraft just shortly after becoming airborne still over the runway. This picture however already shows the RAT extended, hence the abnormal situation indicated by the RAT extension already occurred prior to reaching 180 KIAS, hence prior to 08:08:42z and therefore also prior to the fuel switches transitioning to CUTOFF. Sixth Observation The preliminary report makes clear, that the gear lever was still in the down position and was never attempted to be put up. Usually the pilot monitoring - the captain - would announce "positive rate of climb", the pilot flying - the first officer - would then command "Gear up!" and the captain would move the lever and confirm "Gear coming up". This procedure would likely have the pilot communication "positive rate of climb", "gear up" command and the gear lever put into the up position below 75 feet AGL. However, this did not occur, it is thus likely, that the pilots noticed an anomaly before the call "positive rate of climb". None of this is mentioned in the preliminary report, hence it remains unclear whether none of these calls occurred - or were just not mentioned in the selective excerpt. It thus also remains unclear why the gear lever was, according to the preliminary report, never moved into the gear up position. If we assume that one of the pilots intentionally brought the aircraft down, it is quite possible and even likely, that such calls were not made this time. But then in this scenario, why do the engines run down prior to the actual deed of putting the fuel switches intentionally into CUTOFF? So, we have six observations based on the preliminary report, the videos and the Boeing Manuals suggesting that the engines began to run down before the fuel switches were brought into the position CUTOFF. So, why the fuel switch transition from RUN to CUTOFF and back to RUN? The memory items for dual engine failure require the crew to place the fuel switches to CUTOFF and move them back to RUN, as the Boeing Manuals make clear (quoted above). It is possible, that the crew was aware of the necessity to wait between CUTOFF and RUN in order to ensure a proper reset of the EECs as shown by simulator tests following NH-985. The purpose of this is simple: Reset the EEC (Engine Electronic Control), just like CTL-ALT-DEL on a Windows Computer, and at the same time force the EEC to switch to the other channel, in the hope that this will enable at least one engine if not both engines to recover and run again. As we know from the preliminary report, this nearly worked, one engine had already started to recover but had not yet reached sufficient thrust to prevent the crash. Now, the question is what we conclude from the preliminary report's statement reading: "In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so." This is not a verbatim quote, but a summarizing narrative which does not establish the context of that exchange, and may even be misleading of what was really communicated between the pilots. Only a proper transcript of the entire communication can clarify the context and the exact wording. Could the scenario be that the crew noticed the engines running down, and after overcoming the surprise effect one pilot reminds the other to perform the memory items - "Did you do the CUTOFF?" and the other responds "No" and now performs these memory items? I believe therefore, that the transition of the fuel switches from RUN to CUTOFF was indeed done by the crew with intention, as a reaction to observing both engines running down. However, this was not the start of the crash sequence nor was the intention to bring the aircraft down, rather it was the intention to save the aircraft by at least relighting one of the engines according to the checklist memory items. Why did the engines run down? This is the decisive question that so far nobody can answer without further evidence, investigation and analysis. There had been a similar case, in which the crew was able to recover the engines, which triggered the Service Bulletin FAA-2021-0273-0013 Attachment 2 of 2021. This could be one possibility of how the simultaneous engine run downs could have been triggered by the simultaneous fault of two active MN4s sitting on the two EECs (with the other two inactive MN4s perhaps unaffected). A bump from the runway, the vertical acceleration of the beginning of lift off could have caused the already cracked, weakened solder balls to temporarily open completely and lose contact, causing the MN4s to send a thrust demand below flight idle to the engine control thus causing the engines run down. This is one of many possibilities (however one that is officially documented). There are certainly other possibilities, too, that need investigation and need to be ruled out. Is it even possible that two independent systems fail at the same time in the same way? On Jan 17th 2008, a British Airways Boeing 777-200 was on final approach to London Heathrow as flight BA-38, when both engines failed on short final causing the aircraft to touch down hard before the runway (but fortunately within the airport perimeter), see our coverage at: Report: British Airways B772 at London on Jan 17th 2008, both engines rolled back on final approach. How it was possible that both engines failed at the same time remained a mystery. In all discussions at the time, nobody (including myself) believed that icing might have played a role, how would two fuel lines and fuel filters ice up independently at the same time to block fuel supply to the engines? The debate of how two engines could run down simultaneously despite being supplied from different fuel tanks and by different fuel lines went on for two years without any resolution, and without any idea that could explain the events, certainly ice was completely ruled out in all these discussions. On Feb 9th 2010, 2 years later, the British AAIB released their final report, concluding that it was indeed icing, that caused both engines to fail, in a way that nobody had ever anticipated and thought about: Due to the supercooled nature of the wings and fuel lines during the cruise and the engines being at idle throughout the continuous descent, ice crystals were able to build on the walls of the fuel lines. On short final when establishing the aircraft on the glideslope the engines needed to be accelerated causing quickly increased fuel demand, and thus fuel pressure, which broke the ice crystals free from both fuel line walls. These ice crystals simultaneously accumulated at the face of the Fuel Oil Heat Exchanger (FOHE) and prevented fuel from being delivered to the engines. The mystery was suddenly resolved and the whole sequence of events logically and plausibly explained. I believe we are again against such a mystery and we might find a similiarly surprising explanation. Summary It is therefore obvious that even on the base of the preliminary report the cause of this crash is anything but clear, any conclusion particularly pertinent the fuel switches and unintentional or intentional malicious human activity is completely premature. As often happens, the humans in the cockpit can no longer defend themselves, and thus become all too easily the scapegoats in the conflict of interest between living parties such as designers, producers, makers, regulators, monitors, airlines, safety departments, dispatchers, maintenance personnel, ground personnel, and even investigators. As such, I always stand by the flight crew until their fault is proven or all other possible causes have been proven to be ruled out. The investigation principles therefore are clear: rule out all technical possibilities as the cause of an occurrence, only then look at the possibilities for human (intentional or unintentional) action to be the cause. India's AIB as well as India's Ministry of Transport were sent a copy of this editorial beforehand but did not comment nor did they answer questions to clarify the sequence of events.

 

 

[Dierk]

Die Theorie ist aus drei Gründen unsinnig:

 

1. Extrem kurze Entscheidungszeit, wenn der Schubverlust tatsächlich unmittelbar vor dem Betätigen der Cutoff Schalter stattgefunden hätte, noch dazu in dieser vulnerablen Flugphase: wie kann in Sekundenbruchteilen eine extrem unwahrscheinliche doppelte und gleichzeitige "engine failure" korrekt erkannt und entsprechend gehandelt werden? Kein Mensch kann das, solange noch Restschub besteht.

 

2. Das aber Restschub besteht, der den Flieger allein durch "spool down" noch im Steigflug (!) auf 180 kts beschleunigt haben soll, ist Grundvoraussetzung für die Hypothese. Da müsste zunächst ein Vergleich der noch verfügbaren Rotationsenergie und der Zunahme von Lageenergie und kinetischen Energie durchgeführt werden. Für Plausibilität!

 

3. Unerklärlich, wieso in einem solchen Szenario auf die Frage, warum der Cutoff durchgeführt wurde, mit "I did not" geantwortet wurde.

 

 

 

Bearbeitet Freitag um 08:46 von Dierk

[Frank Holly Lake]

Die Daten vom FDR und die Geräusche liegen ja schon seit Wochen vor.

Es kann zu 100% jetzt schon gesagt werden,

 

-ob. ZB die TW runterliefen und erst dann die Schalter betätigt wurden im Zuge eines Reset

 

-oder wirkich im vollen Schub die Schalter von den Piloten umgelegt wurden.

 

Und wie Simon schon Schrieb:

 

Wie so oft können sich die Menschen im Cockpit nicht mehr wehren und werden so nur allzu leicht zu Sündenböcken im Interessenkonflikt zwischen lebenden Parteien wie Konstrukteuren, Herstellern, Produzenten, Aufsichtsbehörden, Kontrolleuren, Fluggesellschaften, Sicherheitsabteilungen, Disponenten, Wartungspersonal, Bodenpersonal und sogar Ermittlern.

Als solcher stehe ich immer auf der Seite der Flugbesatzung, bis ihr Verschulden bewiesen ist oder alle anderen möglichen Ursachen nachweislich ausgeschlossen wurden.

 

Die Untersuchungsgrundsätze sind also klar: Alle technischen Möglichkeiten als Ursache eines Ereignisses ausschließen, erst dann die Möglichkeiten menschlichen (absichtlichen oder unabsichtlichen) Handelns als Ursache prüfen.

 

So laufen Untersuchungen ab.

Ich habe keine Ahnung, wieso diese Informationen nicht schon längst veröffentlicht worden sind. Das muss Gründe haben. 

Das ist genau der Grund für die zahleichen Spekulationen,  die so entstehen.

Grüße Frank

 

 

Bearbeitet Freitag um 09:08 von Frank Holly Lake

[Alexh]

vor 3 Minuten schrieb Frank Holly Lake:

 

Das ist genau der Grund für die zahleichen Spekulationen,  die so entstehen.

 

 

Diese Spekulationen finden unter einer sehr kleinen Gruppe interessierter Leute statt. Nur um diese zu befriedigen, würde ich meine Veröffentlichungstaktik auch nicht anpassen. Auf die Operation der 787 und fast alle Passagiere hat dies keine Auswirkung.

 

Gruß Alex

[Johnny]

Die Kernaussage des Aufsatzes ist also, dass die Schalter zwar manuell umgelegt wurden, aber bereits davor kein Schub mehr kam, die Elektrik ausfiel und die RAT ausfuhr. Das würde natürlich alles verändern. 

Dass der Preliminary viele Lücken hat (von Fakten die die Ermittler sicher bereits wissen), lässt diesen Raum für Spekulationen natürlich offen.

Generell sollte man aber davon ausgehen, dass die Untersuchung diese Theorie eindeutig verifizieren oder ausschließen kann. Sicher wissen die Ermittler das auch bereits.

 

Schade, dass das Video, aus dem der Screenshot im Bericht stammt, nicht veröffentlicht wird. Aber auch ohne diesen Screenshot würde die AVH Theorie wahrscheinlich nicht existieren, da dies das erste Bild ist wo man die RAT schon sieht und die Theorie darauf basiert. Die ausgefahrene RAT ist ja ein eindeutiger Hinweis dass bereits seit mind. einige Sekunden vorher schon ein Ausfall der Triebwerke und Elektrik bestand. Wann diese ausgefahren wurde, ist also eine sehr entscheidende Frage und sollte das Umlegen der Schalter danach erfolgt sein, ist das eine 180 Grad Wende.

[Gulfstream]

vor einer Stunde schrieb Frank Holly Lake:

-ob. ZB die TW runterliefen und erst dann die Schalter betätigt wurden im Zuge eines Reset

 

-oder wirkich im vollen Schub die Schalter von den Piloten umgelegt wurden

 

 

 

Hat die 787 keinen 'cont' Schalter bei der ignition (wie andere Modelle)? Ergo müsste nichts umgelegt werden, die Treiber sollten (wenn sie denn können) von alleine wieder hochfahren.

[sharkbay]

vor 15 Minuten schrieb Gulfstream:

 

… die Treiber sollten … von alleine wieder hochfahren.

 

Triebwerke  =  Treiber  !?

 

Gregor

 

[FalconJockey]

vor einer Stunde schrieb sharkbay:

Triebwerke  =  Treiber  !?

Ja, genau, ein Schweizerdeutsches Wort.

[FalconJockey]

vor einer Stunde schrieb Gulfstream:

Hat die 787 keinen 'cont' Schalter bei der ignition (wie andere Modelle)? Ergo müsste nichts umgelegt werden, die Treiber sollten (wenn sie denn können) von alleine wieder hochfahren.

Es kann Defekte an Triebwerken geben, die ein zurücksetzen der FADECs erforderlich macht. Dies geschieht bei vielen Flugzeugtypen durch diese Aktion: CUTOFF-RUN. War bei meiner Falcon EASy so, auf der 787 dürfte es exakt gleich sein.

[Gulfstream]

vor 21 Minuten schrieb FalconJockey:

Es kann Defekte an Triebwerken geben, die ein zurücksetzen der FADECs erforderlich macht. Dies geschieht bei vielen Flugzeugtypen durch diese Aktion: CUTOFF-RUN. War bei meiner Falcon EASy so, auf der 787 dürfte es exakt gleich sein.

Aber in diesen paar Sekunden würde man kaum auf die Idee kommen, dass ein FADEC reset notwendig ist. Würde eine Analyse brauchen, denke ich zumindest. Man würde sich wahrscheinlich auf cont ignition verlassen (aus dem Moment heraus). 

[LS-DUS]

vor 4 Stunden schrieb cloudcruiser228:

Die eigentliche Ursache des Triebwerks­ausfalls bleibt offen: Mögliche Defekte an Leiterplatten (MN4), ungewöhnliche Eisblockaden oder andere seltene Fehler müssen noch untersucht werden.

 

Das sind auch extrem unwahrscheinliche Szenarien, die vom Autor des Artikels (The Aviation Herald) als mögliche Ursachen genannt werden. Eisblockaden bei 40 Grad Temperatur?

Oder gleichzeitiger Ausfall der Leiterplatten. 

 

 

 

[FalconJockey]

vor 7 Minuten schrieb Gulfstream:

Aber in diesen paar Sekunden würde man kaum auf die Idee kommen, dass ein FADEC reset notwendig ist. Würde eine Analyse brauchen, denke ich zumindest. Man würde sich wahrscheinlich auf cont ignition verlassen (aus dem Moment heraus). 

Da stimme ich Dir natürlich zu, generell. Wenn mir beide Triebwerke gleichzeitig ausfallen, gibt es wohl Memory Items, die genau das anweisen: CUTOFF-RUN. Ob man das in so einer Situation soooooooo schnell realisiert und hinkriegt, ist eine andere Sache.

[Dierk]

Ermüdungsrisse können auch ohne "Runway Bump" auftreten. Allein schon durch Vibrationen. 

 

Z.B. hat es mir am Auto vor mehreren Jahren die unterste Wicklung der linken vorderen Stossdämpferfedern abgebrochen. Die Teile wurden beidseits mit den gleichen Originalteilen ersetzt. Nun, Jahre später gab es auf topfebener Asphaltstrecke (keine Wellen, keine Schlaglöcher) bei moderater Geschwindigkeit (50 km/h in der Stadt) plötzlich einen Knall vorne rechts. Mit anschliessendem Scheppern. Jetzt ist also die rechte untere Stossdämpferwicklung gebrochen. Offenbar eine konstruktiv bedingte Schwachstelle der Federn selbst. Ein klassischer Ermüdungsbruch.

 

Nur: dieses Versagen tritt niemals gleichzeitig beidseitig auf (sofern keine ausserordentliche externe beidseitige Überlastung der Grund ist). Der Zeitpunkt des Versagens der zweiten Feder nach Versagen der ersten ist weitestgehend zufällig und keinesfalls im Sekundenbereich. 

 

Entsprechend kann ich diese Leiterplattenhypothese (gleichzeitiges beidseitiges Versagen aufgrund von Ermüdungsrissen im Lötzinn) nicht mal im Ansatz ernst nehmen. 

Bearbeitet Freitag um 12:19 von Dierk

[spornrad]

Die erneute wilde Spekulation von Avherald ist IMHO schon deshalb absurd, weil die AAIB nach Auslesen des FDR natürlich die zeitliche Abfolge ganz genau kennt, viel genauer und sicherer als irgendwelche Videoanalysen. Der vorläufige Bericht wäre dann ja bewusstes und kriminelles Legen einer falschen Fährte. Warum? Da eine Reihe anderer Parteien an der Untersuchung beteiligt sind, würde die AAIB niemals damit durchkommen.

Der AAIB Bericht sagt eindeutig, dass die Cutoff-Schalter zuerst umgelegt wurden und daraufhin die Triebwerke runtergefahren sind.

Quote

The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off.

 

Bearbeitet Freitag um 21:02 von spornrad

[sharkbay]

vor 2 Stunden schrieb FalconJockey:

 

Triebwerke  =  Treiber  !?
 

Ja, genau, ein Schweizerdeutsches Wort.

 

Die Treiber !?

 

Jo sogts meine liabn Schweizer Nochborn, wir san doch do net beim Almauftrieb, gö …

 

  

 

Gregor

 

Bearbeitet Freitag um 14:16 von sharkbay
A bisserl a Gspass muas do sei, gö ;-)

[Hausi122]

vor 1 Stunde schrieb sharkbay:

Die Treiber !?

 

Jo sogts meine liabn Schweizer Nochborn, wir san doch do net beim Almauftrieb, gö …

 

  

 

Gregor

 

Schweizerdeutsch korrekt haben wir die Schub erzeugenden Dinger "Triiber" genannt. Wenn schon, denn schon!

Hausi

[FalconJockey]

Die Kollegen, die bei Emirates&Co arbeiten kennen auch Treiber, Kameltreiber. Oder wie halt deren Chefs heissen.

[sharkbay]

vor einer Stunde schrieb FalconJockey:

Die Kollegen, die bei Emirates&Co arbeiten kennen auch Treiber, Kameltreiber. Oder wie halt deren Chefs heissen.

 

Off-Topic  >

Ja, die kenne ich mittlerweile auch die Kameltreiber bei Emirates, meine Wen(d)igkeit hatte im Jahr 2017 Gelegenheit in LOWW Wien Schwechat bei einer Führung durch einen Airbus A380 von Emirates dabei zu sein. Und da machte ich von dem A380 von Draussen und von Drinnen denkbar viele Aufnahmen, bis sich ein hoch arroganter und unglaublich eingebildeter Emirates Flugbegleiter aufregte, als ich zum Schluss der Führung seine fesche Emirates Flugbegleiter Kollegin ohne jegliche böse Absichten fotografierte und ich danach sowas wie einen Rapport erleben musste. Die Emirates Flugbegleiterin wollte mir sogar mein iPhone aus der Hand nehmen, was ich natürlich entschieden zurückwies. Danach unterhielten sich die beiden Emirates Kameltreiber noch untereinander wegen deren Daumen für mich nach oben oder nach unten … , bis ich schlussendlich wieder in die Freiheit durfte …

 

Ein Mal und nie mehr wieder!

 

Gregor

End Off-Topic

 

 

 

 

Bearbeitet Freitag um 17:21 von sharkbay

[oemlegoem]

Delete

Bearbeitet Freitag um 17:23 von oemlegoem