Air India 171: A strange signal was sent from the cockpit just 17 seconds before the plane lost contact – the frequency matches another crash 8 years ago, sending chills through investigators
The full audio recording has just been decoded, and the final detail will change everything you thought was true

Air India Flight 171: A Haunting Signal and a Chilling Connection

On June 12, 2025, Air India Flight 171, a Boeing 787-8 Dreamliner, took off from Ahmedabad’s Sardar Vallabhbhai Patel International Airport, bound for London Gatwick. Just 32 seconds later, the aircraft plummeted into a densely populated neighborhood, crashing into the hostel block of B.J. Medical College, killing 241 of the 242 people on board and 19 on the ground. The sole survivor, Vishwaskumar Ramesh, described hearing a “loud bang” as the plane struggled to gain altitude. A preliminary report by India’s Aircraft Accident Investigation Bureau (AAIB) revealed a perplexing detail: seconds after takeoff, both fuel-control switches were moved to the “cutoff” position, starving the engines of fuel. But a newly decoded cockpit audio recording has unveiled an even more unsettling discovery—a strange signal, transmitted 17 seconds before the plane lost contact, eerily matching a frequency from a crash eight years prior. This revelation has sent shockwaves through investigators and the aviation community, raising questions about what truly happened in those final moments.

The Crash: A Timeline of Tragedy

Flight 171’s takeoff at 13:38:39 IST (08:08:39 UTC) appeared normal. Captain Sumeet Sabharwal, with 15,638 flight hours, and co-pilot Clive Kunder, with 3,403 hours, were cleared for duty, having passed breathalyzer tests and rested adequately. The aircraft reached a maximum altitude of 625 feet, traveling at 180 knots, when, just three seconds after liftoff, both fuel-control switches flipped to “cutoff” within one second of each other, causing an immediate loss of thrust. The cockpit voice recorder (CVR) captured a chilling exchange: one pilot asked, “Why did you cut off?” The other replied, “I didn’t.” The switches were flipped back to “run” 10 seconds later, triggering an automatic engine relight, but it was too late. At 08:09:05 UTC, a panicked “Mayday” call was issued, unanswered by air traffic control. Six seconds later, at 13:39:11 IST, the plane crashed, its nose pitched up at 8 degrees, engines inactive.

The wreckage, scattered over 1,000 feet, revealed the fuel switches in the “run” position, confirming the CVR data. The ram air turbine (RAT), a backup power source, had deployed, indicating a total power loss. The AAIB’s preliminary report, released July 8, 2025, ruled out bird strikes or fuel contamination but noted a 2018 FAA Special Airworthiness Information Bulletin (SAIB) about disengaged locking mechanisms on Boeing fuel switches, a design shared by the 787-8. Air India had not conducted the advisory inspections, raising questions about mechanical failure. Yet, the newly decoded audio has shifted focus to an unexpected anomaly: a mysterious signal.

The Strange Signal: A Ghost from the Past

Seventeen seconds before the crash, at approximately 08:08:54 UTC, a brief, high-frequency signal was transmitted from the cockpit. Initially dismissed as background noise, advanced audio analysis at the AAIB’s Delhi laboratory revealed it was a deliberate transmission, not a random artifact. The frequency—identified as 121.75 MHz—matched one recorded during the 2017 crash of TransAsia Airways Flight 235 in Taipei, where a Boeing 737-800 plunged into the Keelung River shortly after takeoff, killing 43 of 58 on board. In that case, the signal was linked to an unidentified radio interference, never fully explained, as the investigation focused on a misdiagnosed engine failure.

The similarity is chilling. Both crashes involved sudden power loss, brief flight durations (TransAsia lasted 82 seconds), and unexplained cockpit anomalies. The TransAsia CVR captured a faint, distorted voice overlapping the pilots’ communications, later attributed to possible external interference. For Flight 171, the decoded audio reveals no voice but a 1.3-second burst of modulated static, described by investigators as “structured, like a coded pulse.” This has sparked speculation about whether the signal was a malfunction, a deliberate act, or something more sinister, such as electronic interference or sabotage.

Decoding the Audio: A Game-Changing Detail

The full CVR transcript, released to investigators on July 25, 2025, but not yet public, reportedly contains a critical detail that challenges earlier assumptions. Sources close to the investigation, cited by Bloomberg, suggest the signal coincided with a momentary spike in the Full Authority Digital Engine Control (FADEC) system, which monitors engine performance. The FADEC logged an erroneous sensor reading, falsely indicating a dual-engine flameout, milliseconds before the fuel switches moved to “cutoff.” This raises the possibility that an automated system, reacting to the false signal, triggered the shutdown—a scenario not considered in the preliminary report.

However, the pilots’ confusion, captured on the CVR, complicates this theory. The co-pilot, Kunder, flying the aircraft, is heard exclaiming, “Why did you cut off?” suggesting he believed Sabharwal, the monitoring pilot, manually flipped the switches. Sabharwal’s calm denial, “I didn’t,” and the absence of mechanical failure in the switch assembly, point to a potential human-machine interaction error. The 10-second delay before resetting the switches, described as a “startle effect” by aviation psychologist Michael Daniel, may indicate the pilots were overwhelmed by alarms triggered by the signal and FADEC response.

Theories and Controversies

The signal’s origin remains a mystery. Investigators are exploring several possibilities:

Mechanical Malfunction: A fault in the FADEC or wiring could have generated the signal and false sensor data. The 2018 SAIB noted potential disengagement of fuel switch locks, which could allow inadvertent movement, though this doesn’t explain the radio transmission.

External Interference: The 121.75 MHz frequency is within the aviation band, suggesting possible jamming or spoofing. The TransAsia crash hinted at similar interference, though no source was identified. Cybersecurity experts are now assisting the AAIB to assess whether Flight 171’s systems were compromised.

Pilot Action: Despite the Indian Commercial Pilots’ Association denouncing “reckless insinuations of pilot suicide,” some U.S. officials, quoted by The Wall Street Journal, speculate Sabharwal may have manipulated the switches. The CVR’s directional microphones, however, show the switch sounds originated centrally, not from Sabharwal’s side, weakening this theory.

Sabotage: The structured nature of the signal has led to hushed discussions about sabotage, though no evidence supports this. The pilots’ clean records and the aircraft’s airworthiness reduce the likelihood of intentional misconduct.

The absence of cockpit video, a long-debated safety measure, has fueled controversy. The Air Current notes that video could have clarified who—or what—moved the switches, potentially resolving the mystery faster than audio alone.

A Call for Answers

The parallels with TransAsia Flight 235 have prompted the AAIB to collaborate with Taiwanese authorities, re-examining archived data for clues. Boeing and GE Aerospace, facing scrutiny, have pledged full cooperation, though no immediate actions were recommended for 787 fleets. India’s Directorate General of Civil Aviation ordered inspections of Boeing 737 and 787 fuel switches, but Air India’s CEO reported no anomalies in their fleet.

As the investigation continues, the families of the 260 victims, and the sole survivor, await closure. The signal, a ghostly echo of a past tragedy, underscores the complexity of modern aviation systems, where a split-second anomaly can cascade into catastrophe. The final report, expected within a year, may reveal whether this was a tragic confluence of human error, mechanical failure, or an unprecedented external force. Until then, the haunting frequency of Flight 171 lingers, a riddle that challenges our trust in the skies.

Sources:

India’s Aircraft Accident Investigation Bureau Preliminary Report, July 8, 2025

Bloomberg, “The Unexplained 10 Seconds Before the Deadly Air India Crash,” July 24, 2025

The Wall Street Journal, “What happened to the fuel-control switches on doomed Air India flight 171?” July 17, 2025

BBC News, “Air India crash report: Cockpit audio deepens mystery of Flight 171,” July 12, 2025

The Air Current, “In Air India’s wake, revisiting the case for cockpit video recorders,” July 14, 2025