Why is India Publishing Only an Interim Report on Deadly Air India 787 Plane Crash?

As the first anniversary of the deadliest aviation disaster in a decade approaches, India’s Aircraft Accident Investigation Bureau (AAIB) is preparing an interim report rather than a definitive final one on the crash of Air India (AI) Flight AI171. The Boeing 787-8 Dreamliner, registration VT-ANB, departed Sardar Vallabhbhai Patel International Airport (AMD), Ahmedabad, on 12 June 2025, bound for London Gatwick Airport (LGW), and crashed into a densely populated residential area just seconds after liftoff, killing 260 people — 241 of the 242 persons on board and 19 on the ground. A person with direct knowledge of the matter confirmed to Reuters that investigators are not yet in a position to deliver a final report, citing the extraordinary complexity of the probe.

The forthcoming interim document, according to sources cited by Reuters, will be substantially more comprehensive than the 15-page preliminary report released in July 2025, and will examine possible primary causes as well as other contributing factors.

What The Preliminary Report Revealed

The 15-page preliminary report, released by the AAIB on 12 July 2025, provided a stark and troubling timeline: within seconds of liftoff, both engine fuel control switches transitioned from the RUN to the CUTOFF position — one after the other, with an interval of approximately one second. This abrupt cutoff starved both CFM56-class Trent 1000 turbofans of fuel, causing an immediate loss of thrust. The aircraft descended and struck the hostel block of B.J. Medical College, destroying at least five buildings and triggering a post-impact fire.

Investigators confirmed that the Boeing 787-8 had been properly configured prior to departure and lifted off normally. According to the preliminary report, the document presented no evidence of mechanical failure or bird strike that could have simultaneously disabled both engines. Both engines briefly attempted to relight, but only one succeeded in generating thrust — insufficient to prevent the catastrophe.

The AAIB stated at the time that it was “too early to reach any definite conclusions.”

The Cockpit Voice Recorder Reveals a Disputed Exchange

Cockpit voice recorder data added a layer of profound ambiguity to the investigation. The Wall Street Journal, citing sources familiar with the U.S. government’s early assessment reported by Reuters, indicated that the exchange between the two pilots suggested it was the captain who moved the fuel switches, prompting a panicked response from the first officer. The recording reportedly captured one pilot asking, “Why did you cut off?”, to which the other responded, “I didn’t.”

However, this interpretation has since been contested on technical grounds. The Safety Matters Foundation of India (SMF) published photogrammetric analysis in April 2026 asserting that the aircraft’s Ram Air Turbine (RAT) deployed 2.5 seconds before the fuel switches moved to the CUTOFF position.

This sequencing is highly significant: RAT deployment indicates a systemic electrical failure had already occurred before any switch transition, suggesting the movement may not have been the result of deliberate pilot input. The analysis places renewed pressure on the AAIB to address this timing discrepancy in its upcoming interim report.

Why is Air India Not Publishing a Final Report but an Interim One?

Under international aviation law, as codified by the International Civil Aviation Organization (ICAO), a final accident investigation report is due within one year of the incident. If investigators cannot meet that deadline — a not uncommon occurrence in complex accidents — they are required to issue an interim statement on each anniversary until the final report is complete. ICAO’s consultation process for final reports mandates a 30-day comment period, extendable to 60 days, during which participating states can review and respond to draft findings. Crucially, this consultation requirement does not apply to interim statements.

This procedural distinction carries significant practical consequences. By releasing an interim rather than a final report, Indian authorities are not obligated to share findings in advance with the U.S. National Transportation Safety Board (NTSB), which participates in the investigation by virtue of the Boeing 787’s design and manufacture in the United States.

The NTSB would retain the right to comment on any eventual final report — a mechanism that, as Reuters noted, could ultimately provide greater closure for the families of the 260 victims. Both ICAO and the NTSB declined to comment on the matter.

The Parallels with Ethiopian Airlines 737 MAX

The decision to issue an interim rather than a final report is not unprecedented in high-profile investigations. In the case of the Ethiopian Airlines Boeing 737 MAX crash of March 2019, Ethiopian investigators published a detailed interim report within a year of the accident. However, the final report did not emerge until December 2022 — more than three and a half years after the crash.

The NTSB received its first draft copy in January 2021, underscoring how protracted final-report consultations can become when multiple states and manufacturers are involved. The Air India AI171 investigation draws a structural parallel: a U.S.-built aircraft, a non-U.S. investigating authority, and a manufacturer — Boeing — that is simultaneously a technical adviser to the probe and a party with material interests in its conclusions.

Boeing has maintained throughout the investigation that it is “supporting” Air India, and referred Reuters to the AAIB for comment when approached about the interim report. The manufacturer’s dual role — serving both as a technical adviser and as the producer of aircraft or systems under examination — has prompted recurring debates within aviation safety circles about perceptions of investigative independence, though such participation is standard practice under ICAO protocols.

The February 2026 London Incident: Fuel Switches Back in Focus

The investigation’s urgency deepened in February 2026 when pilots operating Air India Flight AI132, a Boeing 787 Dreamliner registered VT-ANX, from London Heathrow Airport (LHR) to Bengaluru Kempegowda International Airport (BLR), reported that the left engine’s Fuel Control Switch (FCS) failed to remain locked in the RUN position during the first two engine-start attempts, stabilizing only on a third attempt before departure. Air India grounded the aircraft upon its arrival in Bengaluru pending investigation.

The UK Civil Aviation Authority (CAA) issued a formal notice to Air India demanding an urgent explanation within seven days and warned of potential fleet-wide enforcement action against the airline’s Dreamliner operations.

Boeing initially told Air India the FCS module was “serviceable”, as seen in an email reviewed by Reuters. The DGCA similarly concluded at first that the anomaly stemmed from pilot error — the result of applying force in an “incorrect direction” against the switch’s angular base plate. However, the regulator subsequently rejected this conclusion and ordered that the component be removed from the aircraft and shipped to Boeing’s manufacturing facility in Seattle for controlled laboratory testing.

DGCA Officials to Observe Boeing Testing in Seattle

The Directorate General of Civil Aviation (DGCA) issued a formal directive on 19 May 2026 ordering that the strip-and-test examination of the FCS module take place in the physical presence of its officers. A 9 March 2026 email from the DGCA, cited in documents reviewed by Reuters, instructed Air India that a DGCA officer must attend Boeing’s premises during the testing. Two senior DGCA inspectors are expected to travel to Seattle in June 2026, with Air India covering the cost of their visit.

Air India stated in a formal communication that the FCS module had already been confirmed as “fully functional” by both Boeing and the DGCA, adding that the additional laboratory examination was being pursued as “a measure of abundant caution” to “definitively confirm its performance and integrity” in a controlled environment.

The DGCA has not indicated whether similar examinations will be extended to additional aircraft in Air India’s 787 fleet, though the outcome of the Seattle tests is expected to carry significant weight in the final report. Notably, some investigators involved in the AI171 probe were not aware of the DGCA’s planned Seattle visit — a detail that signals a degree of fragmentation in the investigative process.

The Federation of Indian Pilots and the Electrical Anomaly Hypothesis

Parallel to the fuel switch inquiry, the Federation of Indian Pilots (FIP), representing over 5,000 aviators across India, formally submitted a technical hypothesis to the Ministry of Civil Aviation and the AAIB asserting that a pre-liftoff electrical disturbance — rather than any deliberate cockpit action — may have triggered the dual-engine fuel cutoff aboard AI171. The FIP urged the AAIB to expand its probe beyond initial findings and to investigate whether an unintended electrical anomaly could have caused both switches to move simultaneously without pilot intervention.

This hypothesis gained additional technical credence from the SMF’s photogrammetric findings regarding RAT deployment timing. In December 2018, the U.S. Federal Aviation Administration (FAA) had also issued a Special Airworthiness Information Bulletin warning of the potential for fuel cutoff switch disengagement on specific Boeing 787-8 aircraft — including the specific part number fitted to VT-ANB, the aircraft that later crashed.

That bulletin was advisory, not mandatory, and according to Air India’s own submissions to investigators, the recommended inspections were never conducted. The FAA, for its part, has publicly maintained that the crash does not appear to have been caused by a mechanical issue.

Fuel Switch Features on the Boeing 787-8 Dreamliner

The Boeing 787-8 Dreamliner’s engine fuel control switches are a subject of particular scrutiny in this investigation. Below is a summary of their key design characteristics and the concerns currently under examination:

• Function: The FCS regulates the flow of jet fuel to each engine; positioned in the RUN setting during normal operations and CUTOFF to shut off fuel supply.
• Design intent: The switches are engineered to require deliberate pilot action before movement, incorporating a locking mechanism intended to prevent inadvertent transition.
• Part number flagged: The FAA’s December 2018 Special Airworthiness Information Bulletin specifically identified a part number fitted to VT-ANB, warning of potential disengagement risk.
• Simultaneous movement: In the AI171 crash, both switches transitioned from RUN to CUTOFF within approximately one second of each other — a sequence investigators have characterised as central to the accident.
• February 2026 incident: On VT-ANX, the left engine FCS failed to hold the RUN position on the first two engine-start attempts in London, suggesting possible locking mechanism inconsistency.
• Testing status: The FCS module from VT-ANX has been removed and sent to Boeing’s Seattle facility; DGCA officials will observe its strip-and-test examination in June 2026.

Air India’s Broader Response

Air India, operating under Tata Group ownership following its privatisation in 2022, has undertaken several institutional measures in the wake of the crash. The airline confirmed via its official newsroom that, in compliance with DGCA directives issued on 14 July 2025, it completed precautionary inspections of the FCS locking mechanism across its entire Boeing 787 and Boeing 737 fleet — with no defects identified.

Air India also suspended 83 wide-body flights for six weeks immediately after the crash to accommodate government-mandated safety checks, and permanently retired flight numbers AI171 and AI172.

Air India CEO Campbell Wilson, speaking to the Tribune India, described the crash as “heartbreaking” and acknowledged the weight it placed on the organisation, while stating that the airline’s job is to keep improving. He confirmed that Air India’s legacy Boeing 787-8 fleet would undergo cabin refurbishment by mid-2027, followed by the Boeing 777 fleet by early 2028, with the first new Dreamliner deliveries expected between December 2026 and January 2027.

The Supreme Court of India, hearing a petition filed by the father of the late captain of AI171, reiterated in November 2025 that the AAIB’s preliminary report did not insinuate pilot fault and that the burden of blame did not rest on the pilot’s family — a ruling that provided partial relief to bereaved relatives while leaving the causal question unresolved.

What Comes Next?

The interim report must still be submitted to Indian government authorities before it can be formally released, and investigators have given no indication of when a final report may follow. The investigation, which involves the AAIB as the lead agency alongside participation from the NTSB, the UK’s Air Accidents Investigation Branch (AAIB UK) — which holds Expert status — and Boeing as a technical adviser, is one of the most internationally scrutinised aviation probes in recent years. The UK AAIB confirmed in a statement that it remains in communication with AAIB India and that “release of information on the investigation rests solely with the Indian authorities.”

Civil Aviation Minister Ram Mohan Naidu has repeatedly urged the public not to rush to conclusions, emphasising that transparency and accountability govern the investigative process. The AAIB itself issued an appeal to the media in July 2025 to “refrain from spreading premature narratives that risk undermining the integrity of the investigative process.”