“There are multiple microphones around the cockpit including their headsets,” said Michael Daniel, a retired Federal Aviation Administration inspector and accident investigator, pointing to a prominent, underappreciated forensic tool of modern aviation disasters. The horrific Air India Flight 171 crash has put the cockpit voice recorder into the spotlight not merely as an innocent bystander, but as a potential arbiter of guilt in the cockpit’s most critical moments.
The initial Indian Aircraft Accident Investigation Bureau (AAIB) report verifies that both fuel control switches on the Boeing 787 Dreamliner were set to CUTOFF immediately after takeoff, cutting fuel supply to the engines and causing an unrecoverable loss of lift. The switches were returned to RUN ten seconds later, but by then the plane had lost the altitude required for recovery and crashed, taking 260 lives. But the enigma of who precisely flipped the switches and for what purpose remains a puzzle.
To prosecutors, however, the CVR is something more than a tape of voices. Its array microphone placed intentionally on the overhead panel and integrated into pilot headsets is capturing not just words but the subtle acoustics of what pilots do in the cockpit: a switch click, a lever being pulled, even spatial information that can give cues about which pilot took a crucial action. As Daniel explained, these sound signatures can be dissected to discern not just the sound of the fuel switches being turned off, but the direction from which it came in the cockpit, offering the potential for near-forensic action localization.
Forensic analysis is laborious. According to the National Transportation Safety Board, a committee that is specially comprised of regulatory agency members, manufacturers, and pilots’ union members listens to and transcribes every second of the CVR, marrying it with flight data and air traffic control tapes in providing an extensive timeline of events that transpired in the cockpit. High-fidelity sound spectrum software can isolate the moment a switch is thrown, relating it to a recognizable voice or even the switch’s physical position in the cockpit.
The design of the 787’s fuel control switches is itself an exercise in engineering protection. Situated in the lower center console, the switches also contain spring-loaded locking levers and metal shields and need to be consciously yanked up in order to shift from RUN to CUTOFF. According to the December 2018 FAA safety bulletin, some Boeing airplanes, including the 787, had experienced installation issues wherein the locking systems were not completely activated, potentially leading to unintended movement. The AAIB report nevertheless indicates that all airworthiness directives applicable to Flight 171 had been fulfilled, and no defects in the switches were reported prior to the accident.
This brings human factors into sharp relief. Aviation safety literature highlights that pilot error in the form of lapses, slips, or mistakes is nevertheless a leading cause of aviation accidents, despite technological progress. Crew resource management and standard operating procedures should lower such risks, but stress cockpit dynamics can still lead to confusion or miscommunication. The CVR transcript of Flight 171 reveals a second of absolute confusion: the junior pilot asked the captain why the fuel switches had been shut off, and the captain denied having touched them. This scene, set against a background of a flight profile disintegrating at an increasing rate, illustrates the challenge of situational awareness and the potential for “slips” even from skilled crews.
The multi-agency investigation underway is typical of the tiered approach of modern accident investigation. Hardware and software logs are being examined by technical specialists, while aviation psychologists and human factors specialists explore cockpit decision-making culture. Involvement by global agencies such as the NTSB and FAA guarantees cross-disciplinary research typical of the global standard of aviation safety.
Regulators have since suggested checks of fuel switches on Boeing fleets of aircraft, while airlines worldwide are already examining CRM training and procedures relating to fatigue. The Indian Commercial Pilots’ Association cautioned against drawing conclusions, stating that “pilots undergo extensive psychological and professional screening, recurrent training, and operate under the highest standards of safety, responsibility, and mental fitness.”
As the investigation goes on, the interplay between cockpit technology, man, and scientific inquiry continues to remain at the forefront of finding answers. The CVR, with its forensic potential, can still provide the last clue as to what and who triggered the fatal sequence on Flight 171.
