July 18, 2025, 05:18:00 GMT
permalink Post: 11924846
Thank you for your reply,
appruser
, and apologies fur cutting most of it:
1. I don't know that the transponder lost power, because I don't have knowledge which electrical bus it is powered from on the 787. It may well have been powered from the main battery the whole time. The FR24 receiver may have stopped receiving data because it could no longer "see" the aircraft‐‐we know there are issues because it didn't even see the eastern half of the runway.
2. Altitudes are rounded, so this could be close to 75 feet gain‐‐or a gain and decline, if the data covers the top of the trajectory.
3. The first reading is definitely in the air, after rotation. FR24 does not report the altitude when the ADS-B data indicates that the aircraft is on the ground, and their data download confirms that.
The best bet to establish timing is to use rotation as datum, and then match the altitude/time estimates from the CCTV with position/time from the ADS-B and the estimated ground speed of the aircraft.
The fact that the ground speed is declining throughout the data sequence strongly suggests that it begins some time after the point, or at the point, when thrust was lost. And we know that didn't begin to happen until the aircraft was 3 seconds into the air.
Big questions in my mind:
1. If the loss of ADSB corresponds to the E1/E2Fuel Cutoff switches being moved from RUN -> CUTOFF, why is the airspeed declining for the prior 4 seconds?
2. In 4 seconds, why is there only 50ft of altitude gain? that seems odd.
3. To account for only 50ft of alt gain, if we assume the 1st reading is on the runway just before rotation, the intermediate +25ft alt gain is at rotation (Nose up but MLG still on the runway), and the last 4 readings are in the air (nose up an additional 25ft), that means that 1 second or less after lift-off, ADSB was lost - this is before E1/E2 FCO RUN-> CUTOFF.
It's just weird .
1. If the loss of ADSB corresponds to the E1/E2Fuel Cutoff switches being moved from RUN -> CUTOFF, why is the airspeed declining for the prior 4 seconds?
2. In 4 seconds, why is there only 50ft of altitude gain? that seems odd.
3. To account for only 50ft of alt gain, if we assume the 1st reading is on the runway just before rotation, the intermediate +25ft alt gain is at rotation (Nose up but MLG still on the runway), and the last 4 readings are in the air (nose up an additional 25ft), that means that 1 second or less after lift-off, ADSB was lost - this is before E1/E2 FCO RUN-> CUTOFF.
It's just weird .
2. Altitudes are rounded, so this could be close to 75 feet gain‐‐or a gain and decline, if the data covers the top of the trajectory.
3. The first reading is definitely in the air, after rotation. FR24 does not report the altitude when the ADS-B data indicates that the aircraft is on the ground, and their data download confirms that.
The best bet to establish timing is to use rotation as datum, and then match the altitude/time estimates from the CCTV with position/time from the ADS-B and the estimated ground speed of the aircraft.
The fact that the ground speed is declining throughout the data sequence strongly suggests that it begins some time after the point, or at the point, when thrust was lost. And we know that didn't begin to happen until the aircraft was 3 seconds into the air.
Last edited by Musician; 18th July 2025 at 05:38 .
July 20, 2025, 18:33:00 GMT
permalink Post: 11925921
The full Flight Global article; those here who chose to put PPRuNe and themselves at risk of legal action by their accusations and emotive language may like to reflect and be more accurate in their contributions to this professional pilots forum in future.
US safety chief supports India’s Aircraft Accident Investigation Bureau in urging media to avoid ‘premature narratives’ about the 12 June disaster that killed 260 people
The head of the US National Transportation Safety Board (NTSB) has criticised recent news stories about the 12 June crash of an Air India Boeing 787-8, aligning with a statement from India’s Aircraft Accident Investigation Bureau (AAIB).
“Recent media reports on the Air India 171 crash are premature and speculative,” NTSB chair Jennifer Homendy said on 18 July. “India’s Aircraft Accident Investigation Bureau just released its preliminary report. Investigations of this magnitude take time.”
Homendy does not specify which media reports she takes issue with.
In recent days, The Wall Street Journal and Reuters, citing unnamed sources familiar with US officials’ assessment of evidence, reported that audio from the crashed jet’s cockpit voice recorder indicates the captain had moved the fuel control switches to the “CUTOFF” position. The reports said that the first officer was the pilot who asked why the switches had been moved.
A source who is also familiar with aspects of the investigation confirms that information to FlightGlobal.
Investigators have not released information to support such a scenario.
NTSB chair Jennifer Homendy warns against “speculative” media reports
The 787-8 was operating flight 171 from Ahmedabad to London Gatwick airport. It crashed shortly after taking off, killing 241 of 242 people aboard and 19 people on the ground.
The AAIB’s 11 July preliminary report said that about 3s after taking off, the two cockpit fuel control switches – each controls fuel to one of the jet’s two GE Aerospace GEnx turbofans – were switched to the “CUTOFF” position. The switch for the left-side engine moved first, with the right-side switch moving within about 1s.
The turbofans then lost thrust. One of the two pilots – the report did not specify which – asked the other why he moved the switch; the other then denied doing so.
Starting 10s after the switches were set to “CUTOFF”, both were switched back to “RUN”, causing the turbofans to begin restarting, but not in time to prevent the jet from crashing.
The 787’s flight data recorder noted the moment the actual physical switch moved to the “CUTOFF” position and then when it moved back to the “RUN” position, a source tells FlightGlobal. Those moments were plotted on a graph showing engine thrust falling off after the switches were moved to “CUTOFF”, and then returning after they were moved to “RUN”.
Because that data reflects the physical movement of the switch, a loss of fuel caused by another problem elsewhere in the 787’s electrical system is unlikely, the source says.
The Federal Aviation Administration on 11 July issued a Continued Airworthiness Notification to the International Community (CANIC) saying that the AAIB’s “investigation to date has found no urgent safety concerns related to the engines or airplane systems of the Boeing Model 787-8”.
On 17 July, the AAIB issued an “Appeal”, saying, “It has come to our attention that certain sections of the international media are repeatedly attempting to draw conclusions through selective and unverified reporting”.
“Such actions are irresponsible… We urge both the public and the media to refrain from spreading premature narratives that risk undermining the integrity of the investigative process,” it adds. “The AAIB appeals to all concerned to await publication of the final investigation report.”
Citing that document, the NTSB’s Homendy said on 18 July, “We fully support the AAIB’s public appeal… and will continue to support its ongoing investigation”.
The AAIB’s preliminary report also notes that the FAA issued a Special Airworthiness Information Bulletin in December 2018 about a “locking feature” within fuel control switches on several Boeing models, including 787s. The locking feature is a safety device that requires the switches be lifted before being transitioned. It involves raised nubs that the switch must transition over.
A fuel control switch similar to that found on Boeing 787s, showing that the switch must transition over raised bumps
That 2018 bulletin warned about potential “disengagement” of the locking feature, which could allow the switches to “be moved between the two positions without lifting”, potentially causing “inadvertent” engine shutdown.
Though the FAA recommended inspections, its bulletin concluded that issue was “not an unsafe condition that would warrant airworthiness directive”.
The FAA reiterated that position in its 11 July CANIC, saying the fuel control switch design does not pose “an unsafe condition”.
Though the AAIB’s report cited the issue, it drew no link between it and the crash
The head of the US National Transportation Safety Board (NTSB) has criticised recent news stories about the 12 June crash of an Air India Boeing 787-8, aligning with a statement from India’s Aircraft Accident Investigation Bureau (AAIB).
“Recent media reports on the Air India 171 crash are premature and speculative,” NTSB chair Jennifer Homendy said on 18 July. “India’s Aircraft Accident Investigation Bureau just released its preliminary report. Investigations of this magnitude take time.”
Homendy does not specify which media reports she takes issue with.
In recent days, The Wall Street Journal and Reuters, citing unnamed sources familiar with US officials’ assessment of evidence, reported that audio from the crashed jet’s cockpit voice recorder indicates the captain had moved the fuel control switches to the “CUTOFF” position. The reports said that the first officer was the pilot who asked why the switches had been moved.
A source who is also familiar with aspects of the investigation confirms that information to FlightGlobal.
Investigators have not released information to support such a scenario.
NTSB chair Jennifer Homendy warns against “speculative” media reports
The 787-8 was operating flight 171 from Ahmedabad to London Gatwick airport. It crashed shortly after taking off, killing 241 of 242 people aboard and 19 people on the ground.
The AAIB’s 11 July preliminary report said that about 3s after taking off, the two cockpit fuel control switches – each controls fuel to one of the jet’s two GE Aerospace GEnx turbofans – were switched to the “CUTOFF” position. The switch for the left-side engine moved first, with the right-side switch moving within about 1s.
The turbofans then lost thrust. One of the two pilots – the report did not specify which – asked the other why he moved the switch; the other then denied doing so.
Starting 10s after the switches were set to “CUTOFF”, both were switched back to “RUN”, causing the turbofans to begin restarting, but not in time to prevent the jet from crashing.
The 787’s flight data recorder noted the moment the actual physical switch moved to the “CUTOFF” position and then when it moved back to the “RUN” position, a source tells FlightGlobal. Those moments were plotted on a graph showing engine thrust falling off after the switches were moved to “CUTOFF”, and then returning after they were moved to “RUN”.
Because that data reflects the physical movement of the switch, a loss of fuel caused by another problem elsewhere in the 787’s electrical system is unlikely, the source says.
The Federal Aviation Administration on 11 July issued a Continued Airworthiness Notification to the International Community (CANIC) saying that the AAIB’s “investigation to date has found no urgent safety concerns related to the engines or airplane systems of the Boeing Model 787-8”.
On 17 July, the AAIB issued an “Appeal”, saying, “It has come to our attention that certain sections of the international media are repeatedly attempting to draw conclusions through selective and unverified reporting”.
“Such actions are irresponsible… We urge both the public and the media to refrain from spreading premature narratives that risk undermining the integrity of the investigative process,” it adds. “The AAIB appeals to all concerned to await publication of the final investigation report.”
Citing that document, the NTSB’s Homendy said on 18 July, “We fully support the AAIB’s public appeal… and will continue to support its ongoing investigation”.
The AAIB’s preliminary report also notes that the FAA issued a Special Airworthiness Information Bulletin in December 2018 about a “locking feature” within fuel control switches on several Boeing models, including 787s. The locking feature is a safety device that requires the switches be lifted before being transitioned. It involves raised nubs that the switch must transition over.
A fuel control switch similar to that found on Boeing 787s, showing that the switch must transition over raised bumps
That 2018 bulletin warned about potential “disengagement” of the locking feature, which could allow the switches to “be moved between the two positions without lifting”, potentially causing “inadvertent” engine shutdown.
Though the FAA recommended inspections, its bulletin concluded that issue was “not an unsafe condition that would warrant airworthiness directive”.
The FAA reiterated that position in its 11 July CANIC, saying the fuel control switch design does not pose “an unsafe condition”.
Though the AAIB’s report cited the issue, it drew no link between it and the crash