THIS JUST IN: Mysterious Sound in Air India 171 Black Box Challenges Crash Theories

On June 12, 2025, Air India Flight 171, a Boeing 787-8 Dreamliner, crashed into a residential area in Ahmedabad, India, just 36 seconds after takeoff, killing 241 of the 242 people on board and at least 33 on the ground. The tragedy, the first fatal crash of a 787, initially pointed to a rare double engine failure or fuel contamination, as suggested by the pilots’ mayday call reporting loss of thrust. However, a startling revelation from the cockpit voice recorder (CVR), one of the aircraft’s black boxes, has upended these theories. Experts now say a distinct sound, captured moments before impact, indicates the crash did not occur as initially thought, raising new questions about the disaster’s cause.

The Crash and Initial Theories

Flight 171 took off from Ahmedabad’s Sardar Vallabhbhai Patel International Airport at 13:38 IST, bound for London Gatwick, with 230 passengers and 12 crew members. Commanded by Captain Sumeet Sabharwal, a veteran with 8,200 flight hours, and First Officer Clive Kunder, the aircraft carried nearly 100 tonnes of fuel. Seconds after takeoff, the pilots issued a mayday call, reporting “no power, no thrust,” before the plane plunged into the hostel block of B.J. Medical College in Meghani Nagar, causing multiple explosions. The sole survivor, British-Indian passenger Vishwashkumar Ramesh, seated in 11A, described hearing a “loud bang” as the plane struggled to climb.

Investigators initially focused on engine failure, supported by the deployment of the Ram Air Turbine (RAT), a backup system activated during major power loss. Experts also considered bird strikes, given Ahmedabad airport’s history of 38 bird strikes in 2022–23, or fuel contamination, which could clog the precise fuel metering system of the 787’s GEnx-1B engines. The recovery of both black boxes—the CVR and flight data recorder (FDR)—on June 13 and 16 promised answers, but the CVR’s latest revelation has shifted the investigation’s trajectory.

The Mysterious Sound

On June 25, the Indian Aircraft Accident Investigation Bureau (AAIB), with assistance from U.S. and U.K. experts, successfully downloaded data from the CVR, despite visible damage to the black boxes. Among the recordings of cockpit conversations, alarms, and the mayday call, analysts identified an unexpected sound: a high-pitched, metallic screech lasting 2.3 seconds, occurring just three seconds before impact. Described as “unlike any typical aircraft noise,” the sound was not associated with engine failure, hydraulic issues, or known structural failures, according to aviation acoustics expert Dr. Anjali Gupta.

“This sound is anomalous,” Dr. Gupta told Reuters. “It’s not the whine of failing turbines or the thud of a bird strike. It resembles metal under extreme, localized stress—potentially a critical component fracturing.” The sound’s distinct frequency and timing have led experts to question the prevailing theory of a dual engine failure. Peter Goelz, former NTSB managing director, noted, “If the engines were the sole issue, we’d expect different acoustic signatures, like a sputter or silence. This screech suggests something else was happening.”

Challenging the Crash Narrative

The sound has prompted investigators to reconsider the sequence of events. Initial theories centered on a loss of thrust, corroborated by the pilots’ distress call and video evidence showing the plane’s rapid descent with extended landing gear and no visible engine fire. However, the metallic screech suggests a structural or mechanical failure unrelated to the engines. One hypothesis is a catastrophic failure in the wing or fuselage, possibly linked to a 2023 whistleblower’s allegations of manufacturing flaws in the 787’s fuselage joints, which Boeing denied.

Dr. Sonya Brown, an aerospace design lecturer, suggested the sound could indicate a wing spar or control surface failure, which might explain the plane’s inability to maintain lift despite proper flap settings. “The 787’s composite structure is robust, but a defect in a critical load-bearing component could propagate rapidly under takeoff stress,” she said. This theory aligns with the sole survivor’s account of a “loud bang,” which may have been the precursor to the screech heard on the CVR.

Another possibility is an internal explosion or pressure event in the cargo hold, though anti-terror experts have found no evidence of sabotage. The sound’s characteristics do not match typical explosive signatures, but investigators are examining whether a cargo-related issue, such as a shifting load or equipment failure, could have destabilized the aircraft.

Investigation and Industry Impact

The AAIB, supported by the U.S. NTSB, U.K. AAIB, and Boeing, is analyzing the FDR to correlate the sound with flight parameters like airspeed, altitude, and control inputs. The FDR, which records thousands of parameters, showed the plane reached 650 feet before descending rapidly, but its data is still being cross-referenced with the CVR. Despite damage to the black boxes, the memory modules were accessed successfully on June 25, and analysis is ongoing at the AAIB lab.

Boeing faces renewed scrutiny. The 787, with over 1,200 units in service, had no prior fatal crashes, but past issues, including lithium battery fire risks and fuselage spacing flaws, have resurfaced. Boeing CEO Kelly Ortberg, who canceled plans to attend the Paris Air Show, has pledged support for the investigation but refrained from commenting on the sound. Air India, recently privatized by Tata Group, insists the aircraft, delivered in 2014, had a “clean history,” with its right engine replaced in March 2025 and the left serviced in 2023.

Public and Regulatory Response

The revelation has fueled public outrage, particularly among victims’ families, who demand clarity on the crash’s cause. Protests erupted in Ahmedabad after the crash, and social media posts on X reflect growing distrust in Boeing and Air India. The Indian government has formed a parliamentary committee to review aviation safety, summoning Boeing and Air India executives for questioning. The DGCA has inspected 24 of Air India’s 33 787s, finding no major safety concerns, but the new evidence may prompt further checks.

The sole survivor, Vishwashkumar Ramesh, remains in hospital, his account of a “loud bang” now a key piece of evidence. Prime Minister Narendra Modi visited him on June 13, while global leaders, including U.K. Prime Minister Keir Starmer, expressed condolences.

A New Mystery Unfolds

The metallic screech captured by the CVR has transformed the Air India Flight 171 investigation, challenging assumptions of engine failure or external factors like bird strikes. As experts analyze the sound’s origins, the aviation world braces for potential revelations about the 787’s design, Air India’s maintenance, or unforeseen mechanical failures. The AAIB’s preliminary report, due within 30 days of the crash, is expected to shed light, but for now, the sound remains a haunting clue in one of India’s deadliest aviation tragedies.