Air India crash

[facthunter]

Complete structural inadequacy of the forward part of the fuselage. Came on after Pressurisation cycles accumulated . Eventually checked under water. To their credit De Havs made all their findings Known to other Aviation Builders. The Perils of Pioneering .  Nev

[BrendAn]

1 hour ago, facthunter said:

Complete structural inadequacy of the forward part of the fuselage. Came on after Pressurisation cycles accumulated . Eventually checked under water. To their credit De Havs made all their findings Known to other Aviation Builders. The Perils of Pioneering .  Nev

you might call that experimental.

[Roundsounds]

2 hours ago, spacesailor said:

Just like the English " DH Comet " three crashed .

Then after a short inquiry,  they went back into service .

Only to be grounded for design faults and build faults. 

spacesailor

 

There are no design faults, contaminated fuel or any technical reason as to why the airplane crashed. 

[onetrack]

From a Flight Operations Briefing Note:

 

Introduction:

The failure rate of aircraft engines has reached an all-time low. This means that many flight crews will never face an engine failure during their career, other than those in the flight simulator.

However, simulators are not fully representative of engine failures because accelerations (e.g. due to a failed engine), noise (e.g. caused by an engine stall), or vibrations (e.g. in the event of a blade rupture), are hard to simulate.

Consequently, flight crews are not always able to identify and understand engine malfunctions. Incorrect crew understanding of engine malfunctions can lead to unnecessary engine shutdowns, but also to incidents and accidents.

 

Statistics and Background:

When the jet engine was introduced in civil aviation in the 1950s (de Havilland Comet, Sud-Aviation Caravelle), the available thrust was less than 10,000 lbs. Today, high by-pass ratio engines produce up to 115,000 lbs of thrust.

During the same time, the rate of In-Flight Shut Downs (IFSD) has decreased as follows:

 

IFSD (per 100,000 engine FH)

 

1960s - 40

Today - Less than 1

 

In other words:

• In the 1960s, on average, each engine failed once a year

• Today, on average, each engine fails every 30 years.

 

This improvement in the rate of IFSD has allowed the introduction of ETOPS (Extended Twin Operations) in 1985.

Among other criteria, to be approved for ETOPS 180, the rate of IFSD must be less than 2 per 100,000 engine flight hours.

 

This also means that pilots that start their career today, will probably never experience an IFSD due to an engine malfunction.

However, despite the significant improvement in engine reliability, the number of accidents (per aircraft departure) due to an incorrect crew response following an engine malfunction, has remained constant for many years.

 

This prompted a study with all major industry actors involved (aircraft and engine manufacturers, authorities, accident investigation agencies, pilot organizations).

Among the results were:

• The vast majority of engine malfunctions are identified and handled correctly. However, some malfunctions are harder to identify

• Most crews have little or no experience of real (i.e. not simulated) engine malfunctions

• Simulators are not fully representative of all malfunctions

• Training does not sufficiently address the characteristics of engine malfunctions.

 

The following crew undue actions, caused by engine malfunctions, have been observed:
• Loss of control (trajectory not adapted to the engine failure)
• Rejected takeoff above V1
• Shutdown of the wrong engine
• Unnecessary engine shutdown
• Application of the wrong procedure / Deviation from the published procedure. 

[Roundsounds]

4 hours ago, onetrack said:

There is nothing in the information coming out that says the fuel cutoff switches were actually moved. All that has been stated, is that the investigation is "focusing on the fuel switches".

 

No doubt the investigation is carefully studying the maintenance records and interrogating those who last worked on the aircraft. It is a worrying sign that falsified and inadequate aviation records have been provided by Air India Express staff previously.

“July 8 (Reuters) - The investigation into the Air India flight 171 crash has zeroed in on the movement of the engine fuel control switches, following an analysis of the Boeing 787's flight and voice data recorders, the Air Current reported on Tuesday.”

 

focus seems to be “on the movement of the engine fuel control switches”

 

[Garfly]

FWIW a discussion of those switches by Mentour and mate:

 

https://www.youtube.com/watch?v=cQakAafxGck

 

[IBob]

The prinicipal suggestions that come out of that would seem to be:
1. Due to their mechanical design, those switches cannot be accidentally tripped.
2. For the aircraft to behave as it did (without yawing) they would have to both be operated more or less simultaneously.

I did freelance industrial automation work for over 30years. Much of it was quite straightforward, but over half of any program I wrote would be made up of 'what ifs'. That is, how the system should respond in the event of a failure of some part of the equipment or system. (And I always made a point of running that past the actual operators or end users, the reason being that they, not management, were usually the most knowledgeable when it came to the process.)

 

So, those switches are not just a couple of switches wired to fuel valve. My guess would be there will be switches or contacts for both open and shut positions. And that will go to some sort of logic, which operates the valves. And aside from normal operation, the logic has to include what if power is lost to a switch or switches, what if a switch fails etc. Also under what other conditions (if any) are the fuel valves allowed to change state.
It would be very interesting to see the actual switch arrangement, circuitry and logic...........

[BrendAn]

On 10/07/2025 at 6:50 PM, facthunter said:

Complete structural inadequacy of the forward part of the fuselage. Came on after Pressurisation cycles accumulated . Eventually checked under water. To their credit De Havs made all their findings Known to other Aviation Builders. The Perils of Pioneering .  Nev

there was a good documentary on the comet investigation.  wasn't that the start of major accident investigations. i don't think anything so thorough had been done before.

[Thruster88]

*** Air India Preliminary Report ***

On 12th June 2025, Air India’s B787-8 aircraft bearing registration VT-ANB arrived at Ahmedabad airport operating flight AI423 from Delhi. The aircraft touched down at 05:47 UTC (11:17 IST) and was parked at the bay 34.
  
The crew of the previous flight (AI423) had made Pilot Defect Report (PDR) entry for status message “STAB POS XDCR” in the Tech Log. The troubleshooting was carried out as per FIM by Air India’s on duty AME, and the aircraft was released for flight at 0640 UTC.
  
The aircraft was scheduled to operate flight AI171 from Ahmedabad to Gatwick with ETD 07:40 UTC (13:10 IST). The flight was to be operated by the flight crew comprising an ATPL holder PIC, a CPL holder Co-pilot along with ten cabin crew. Both pilots were based at Mumbai and had arrived at Ahmedabad on the previous day. They had adequate rest period prior to operating the said flight. The co-pilot was Pilot Flying (PF), and the PIC was Pilot Monitoring (PM) for the flight. 

The crew of flight AI171 arrived at the airport and underwent preflight Breath Analyzer test at 06:25 UTC and were found fit to operate the flight. The crew is seen arriving at the boarding gate in the CCTV recording at about 07:05 UTC (12:35 IST).  

There were 230 passengers on board, out of which 15 passengers were in business class and 215 passengers were in economy class including two infants. 

Fuel on board was 54,200 Kgs and as per the load and trim sheet of the flight, the Take-off Weight was 2,13,401 Kgs (Max. allowed - 2,18,183 Kgs). The take-off weight was within allowable limits for the given conditions. There was no ‘Dangerous Goods’ on the aircraft.   

The calculated V speeds with available conditions at Take-Off were V1 - 153 Kts, Vr - 155 Kts, V2 -162 Kts. 

The A-SMGCS replay of the flight was also carried out after the accident. The aircraft was observed departing from the bay 34 at 07:48:38UTC. The taxi clearance was received at 07:55:15 UTC and the aircraft taxied from the bay at 07:56:08 UTC. The aircraft taxied to Runway 23 via Taxiway R4, backtracked and lined up. The take-off clearance was issued at 08:07:33 UTC. The aircraft started rolling at 08:07:37 UTC.  

As per the EAFR data, the aircraft crossed the take-off decision speed V1 and achieved 153 kts IAS at 08:08:33 UTC. The Vr speed (155 kts) was achieved as per the EAFR at 08:08:35 UTC. The aircraft air/ground sensors transitioned to air mode, consistent with liftoff at 08:08:39 UTC.  

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. 

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.  

The CCTV footage obtained from the airport showed Ram Air Turbine (RAT) getting deployed during the initial climb immediately after lift-off. No significant bird activity is observed in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall.

As per the EAFR data both engines N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC. 

As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.  

The EGT was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC 

At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”. The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response. 

At 08:14:44 UTC, Crash Fire Tender left the airport premises for Rescue and firefighting. They were joined by Fire and Rescue services of Local Administration. 

Accident involving Air India’s B787-8 aircraft bearing registration VT-ANB at Ahmedabad on 12 June 2025

General Information 
1.  Aircraft  Type  Boeing 787-8 
 Nationality  Indian 
 Registration  VT-ANB 
2.  Owner and Operator  Air India 
3.  Pilot  ATPL Holder 
 Extent of Injuries  Fatal 
4.  Co Pilot  CPL Holder 
 Extent of Injuries  Fatal 
5.  No. of Persons on board  230 passengers, 10 Cabin Crew and 02 Flight Crew 
6.  Date & Time of Accident  12 June 2025, 0809 UTC (13:39 IST) 
7.  Place of Accident  Ahmedabad 
8.  Co-ordinates of Accident Site       23°03'17.8"N 72°36'43.6"E 
9.  Last point of Departure  Sardar Vallabhbhai Patel International Airport (VAAH)  
10.  Intended landing place  London Gatwick Airport (EGKK) 
11.  Type of Operation  Scheduled Passenger  
12.  Phase of operation  Initial Climb 

Injuries to persons 
Injuries  Crew  Passengers  Others 
Fatal  12  229  19 
Serious  NIL  1  67 
Minor/None  NIL  NIL  

Aircraft Information 
Aircraft Model  Boeing 787-8 
Aircraft Sr. No.  36279  
Year of Manufacturer of Aircraft  2013  
Name of Owner  Air India Limited 
Certificate of Registration  4475/4 
Certificate of Airworthiness  6584 valid subject to the validity of Airworthiness 
Review Certificate (ARC) 
Last ARC issued on  22 May 2025 
ARC valid up to  23 May 2026 
Category  Normal (Passenger/Mail/Goods) 
Total Aircraft Hours  41868  
Engine Type Left Hand (LH)  GEnx-1B70/75/P2 
Date of Manufacture of Engine (LH)  20 May 2012 
Engine Sl. No. (LH)  956174 
Total Engine Hours/Cycles (LH)  27791:43/4298 
Engine Type Right Hand (RH)  GEnx-1B70/P2 
Date of Manufacture of Engine (RH)  21 Jan 2013 
RH Engine Sl. No. (RH)  956235 
Total Engine Hours / Cycles (RH)  33439:30/ 6202 

The last major line maintenance check as per the Aircraft Maintenance Program was L1-1 and L1-2 check carried out at 38504:12 Hrs and 7255 cycles. The next major check (D Check) was due on the aircraft in Dec 2025. 

The LH Engine with ESN956174 was installed on 01 May 2025 and the RH Engine with ESN956235 was installed on the aircraft on 26 Mar 2025. 

There were four CAT ‘C’ Minimum Equipment List (MEL) items active on aircraft as of 12.06.2025. These MELs were invoked on 09.06.2025 and validity of these MEL were till 19.06.2025. These MEL were for flight deck door visual surveillance, airport map function, core network, FD printer.  

There was a CAT A MEL active w.r.t. Nitrogen generation performance, which was valid till 20.06.2025. There were other Category D MELs/NEFs on the aircraft related to cabin and cargo, the validity of these MELs were also within the due date.   
All applicable Airworthiness Directives and Alert Service Bulletins were complied on the aircraft as well as engines.
 
The FAA issued Special Airworthiness Information Bulletin (SAIB) No. NM-18-33 on December 17, 2018, regarding the potential disengagement of the fuel control switch locking feature. This SAIB was issued based on reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The airworthiness concern was not considered an unsafe condition that would warrant airworthiness directive (AD) by the FAA. The fuel control switch design, including the locking feature, is similar on various Boeing airplane models including part number 4TL837-3D which is fitted in B787-8 aircraft VT-ANB. As per the information from Air India, the suggested inspections were not carried out as the SAIB was advisory and not mandatory. The scrutiny of maintenance records revealed that the throttle control module was replaced on VT-ANB in 2019 and 2023. However, the reason for the replacement was not linked to the fuel control switch. There has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB.

Damages 
The Aircraft was destroyed due to impact with the buildings on the ground and subsequent fire. A total of five buildings shown in the figure below were impacted and suffered major structural and fire damages.  

Wreckage and Impact
After takeoff, the aircraft impacted the BJ Medical College hostel which is 0.9 NM from the departure end of Runway 23. The Emergency Locator Transmitter (ELT) was not activated during this event. The wreckage, from the first impact point till the last identified aircraft item, was distributed in an area of approx. 1000 ft * 400 ft. A layout of the crash site is shown in the photos attached indicating the significant parts of the aircraft. The buildings at the wreckage site have been labelled alphabetically from A-F in the layout for easy reference. 

As the aircraft was losing altitude, it initially made contact with a series of trees and an incineration chimney inside the Army Medical Corps compound before impacting the northeast wall of the Building A. The distance between the tree on which the aircraft made its initial contact and the point on the Building A where the aircraft impacted is 293 ft. As the aircraft moved forward, it continued fragmenting and collided with other structures and vegetation. The impact witness marks on the building and airplane indicated a likely nose-up attitude (about 8°) and wings level. 

The vertical stabilizer (fig. 5) separated from the aft fuselage and came to rest about 200 feet south of the initial point of contact with the Building A. The tail section and the RH Main Landing Gear (MLG) of the aircraft were found embedded in the northeast wall of the Building A while the rest of the airplane continued its forward movement.

As the airplane continued its path across the roof of the Building A the right engine struck the concrete water tank structure, separated from the airplane and rested underneath the water tank structure facing a heading of approx. 226 degrees near south west wall of the Building A.

The inboard parts of the right wing were found in Buildings A & B and the areas surrounding the buildings.

The right-wing mid-section and the outboard section was about 280 feet and 520 feet southwest respectively from the initial point of contact with the Building A. The left main landing gear (LH MLG) and left wing outboard and middle section struck building C, came to rest approx. 345 feet south from the initial point of contact. The left wing middle section of the wing was stuck in the north corner of the fourth floor of the Building C while the left wing inboard section was lying about 670 feet southwest of the initial point of contact with the Building A. The nose landing gear (NLG) was found on the ground about 307 feet southwest from the initial point of contact with Building A. The left engine got separated from the airplane and struck the north corner of Building D at the ground level where it remained and was roughly perpendicular to the right engine resting position, at heading of approx. 326 degrees. The wall was pushed into the building and the northwest building column was damaged such that portions of the concrete were missing and exposing the internal metal rebar. The engine, remaining portions of attached cowling, and the surrounding area were heavily damaged by fire. After the tail section was brought down, the APU was inspected and found intact inside the APU compartment. The APU air inlet door, which was intact, was found open. The fuselage fragmented and sustained thermal damage as it traveled along the northwest faces of Buildings C, D, E, and F with the furthest debris observed at about 765 feet southwest from the initial point of contact with building A. The flight deck area and windshield support structure came to rest at about 650 feet southwest from the initial point of contact with Building A.

The flap handle assembly sustained significant thermal damage. The handle was found to be firmly seated in the 5-degree flap position, consistent with a normal takeoff flap setting. The position was also confirmed from the EAFR data. The landing gear lever was in “DOWN” position. The thrust lever quadrant sustained significant thermal damage. Both thrust levers were found near the aft (idle) position. However, the EAFR data revealed that the thrust levers remained forward (takeoff thrust) until the impact. Both fuel control switch were found in the “RUN” position. The reverser levers were bent but were in the “stowed” position. The wiring from the TO/GA switches and autothrottle disconnect switches were visible, but heavily damaged.

The weather as per the Meteorological office at SVPI Airport, Ahmedabad at the time of the accident was as follows:  
 
Time (UTC)  Wind (degre es/Kts)  Visibility (m)  Wx  Cloud  Temp 
(°C)  QNH 
(hPa)  Trend 
0730  240/06  6000  -  NSC  36  1001  Not Significant 
0800  250/07  6000  -  NSC  37  1001  Not Significant 
0830  240/03  6000  -  NSC  37  1000  Not Significant 
0900  260/06  6000  -  NSC  38  0999  Not Significant 

The Aerodrome Sardar Vallabhbhai Patel International Airport, Ahmedabad is a DGCA licensed airport having a license valid up to 09/06/2028. The ARFF category at the airport as per the AIP is Category 9. 

Communications  
After the accident the ATC data was preserved. The replay of ATC recordings data was conducted. Summary of events based on the replay is as below: 

Time (in UTC)  Event 
07:43:00  The aircraft requested pushback and startup. 
07:43:13   ATC approved pushback. 
07:46:59   ATC approved Start up. 
07:49:12   ATC queried if the aircraft required full length of the runway. The aircraft confirmed requirement of full length of RUNWAY 23. 
07:55:15   The aircraft requested taxi clearance, which was granted by ATC. 
08:02:03   The aircraft was transferred from Ground to Tower Control. 
08:03:45   The aircraft was instructed to line up on the Runway 23. 
08:07:33  The aircraft was cleared for Take-Off from Runway 23, Wind 240°/06 Kts. 
08:09:05  MAYDAY call was made by AI171. 

Flight Recorders 
The aircraft is equipped with two Enhanced Airborne Flight Recorders (EAFR) part number 866-0084-102. The EAFR are fitted at two locations, one in the tail section at STA 1847 and other in the forward section at STA 335. The two EAFRs are similar in construction and record a combined data stream of digital flight data and cockpit voice information, with both stored on the same device. 

The aft EAFR receives electrical power from the aircraft’s main electrical system. The forward EAFR contains an additional power source from the Recorder Independent Power Supply (RIPS), a system that provides electrical power to the forward EAFR in the event of a power or bus loss on the aircraft. This allows the forward EAFR to continue to record available digital flight data, and voice data from the Cockpit Area Microphone (CAM), even after power is lost to other aircraft systems. 

The aft EAFR was located on the roof top of Building A on 13th June 2025. The EAFR had impact and thermal damages to the housing. The wires were protruding from the housing and the connectors were burnt.  

The forward EAFR was located on 16th June 2025 from the wreckage debris besides the Building F. The EAFR was burnt and covered in soot. The EAFR was still attached to the equipment shelf with part of the connector melted but still connected. The ULB was still connected to the housing and the lithium battery was also attached to the equipment shelf, which was removed later prior to transportation.  

Both EAFRs were transported from Ahmedabad to AAIB’s facility at New Delhi on 24th June 2025. Like various other cases where the data from damaged flight recorders was downloaded by AAIB after sourcing ‘Golden Chassis’ and relevant download cables from the DGCA and other Accident Investigation Authorities, in this case the ‘Golden Chassis’ (Identical EAFR unit) and Download cables required to download data from EAFR were sourced from NTSB, USA. The items arrived on 23rd June 2025.  

The download from the FWD EAFR was attempted at the AAIB Lab on 24th June 2025. The CPM was retrieved from the EAFR and found to be in good condition. The CPM was mounted on the Golden Chassis and the raw data was downloaded from the EAFR. 

The downloaded flight data contained approximately 49 hours of flight data and 6 flights, including the event flight. The recovered audio was two hours in length and captured the event. Initial Analysis of the recorded audio and flight data has been done. 

The aft EAFR was substantially damaged and could not be downloaded through conventional means. The CPM was opened to inspect the memory card. The damage was extensive.  

#aviation #travel #safety #safetyfirst #boeing #pilot #flight #BreakingNews

[IBob]

This muddies the waters some:
file:///C:/Users/OEM/Downloads/EASA_SIB_NM-18-33_1.pdf

And how on earth is this, quote : 'not an unsafe condition that would warrant airworthiness directive (AD)'           ????????

[IBob]

Some may find it easier to read the preliminary report in it's original form. It also has some pics:
https://aaib.gov.in/What's New Assets/Preliminary Report VT-ANB.pdf

[red750]

Report this morning that the CVR shows the PIC ask "Why did you cutoff the fuel?" The CP said  "I didn't." No tome to rrestart.

[Garfly]

Mentour and Ben discuss:

https://www.youtube.com/watch?v=SE0BetkXsLg

 

[BrendAn]

It amazes me that those switches are even there. 

[Thruster88]

28 minutes ago, BrendAn said:

It amazes me that those switches are even there. 

There are switches with the same function in every aircraft, including the type you are now flying.

[Garfly]

 

I take it that the fuel cutoffs are placed there very much by design; in the case of an engine malfunction the pilot's hand falls straight to what's likely the next crucial task (after closing the offending throttle). 

[facthunter]

 Used every time you shut down when park brakes applied, before deplaning the Passengers.  Nev

[IBob]

46 minutes ago, Thruster88 said:

There are switches with the same function in every aircraft, including the type you are now flying.

That's not the case at all, Thruster:
My aircraft (for instance) has a little lever that turns a ball valve.
The 787 has a switch that provides at least 2 outputs (one for each switch position, Off or Run) and I would lay odds that those inputs go to automation logic that interprets the switch position and makes a decision regarding the fuel valves etc. That logic would also be trying to deal with fault conditions (both inputs on or both inputs off) and deciding what to do then.
It is interesting that the switch is reported as taking place immediately after liftoff.......which is also when the logic switches from ground to flight mode.
There also seem to be the general assumption that the FDR info is taken straight from the switch. And maybe it is, but it seems likely to me that it is taken after the logic has decided where the switch is.

[facthunter]

Seems Likely is not part of a finding worth anything. The action of those switches is (intended) to shut off the fuel. Another function (in that plane) is a rapid relight when in the air.   Takes over 20 seconds. A once in many lifetimes event. Nev

[IBob]

46 minutes ago, facthunter said:

Seems Likely is not part of a finding worth anything. The action of those switches is (intended) to shut off the fuel. Another function (in that plane) is a rapid relight when in the air.   Takes over 20 seconds. A once in many lifetimes event. Nev

Which bit, Facthunter???

 

[facthunter]

I have no idea what you mean.  Nev

[IBob]

Which part of finding is not worth anything?

 

[facthunter]

Things like seems likely and might. nev

[IBob]

Okay. I was trying to raise what I see as valid points. But they are hard to explain, so I'll leave it.

[kgwilson]

I still reckon the system shut the fuel off as it got an instruction from some other part of the system that the valves were to be closed, so that's what it did.