Past air crash investigations show how rare and complex aircraft-assisted suicides are — experts call for caution before linking depression or cockpit behaviour with intentional crashes
New Delhi – The tragic crash of Air India Flight AI-171, en route from Ahmedabad to Gatwick on June 12, has led to renewed attention on the mental health of pilots after early reports speculated possible sabotage. All 241 people on board died, along with 19 on the ground. Though the official investigation is still in its early stages, questions are already being raised over whether the crash was intentional.
However, experts caution against jumping to conclusions. A small number of previous incidents where pilots were suspected of intentionally crashing planes show how rare, complex and difficult it is to determine intent. Pilot associations in India have criticized the early speculation, urging the media and public to wait for full facts before assigning blame.
A Pattern That Rarely Exists
According to aviation researchers, since 1994, there have only been six confirmed global cases where commercial flights crashed due to intentional actions by pilots. Among them, only four have been studied in-depth in academic journals. In all cases, proving intent required years of investigation and psychological assessment of the deceased pilot — a process known as a “psychological autopsy”.
Even then, experts like Alpo Vuorio, a Finnish psychologist and aviation researcher, say there can rarely be full certainty. “There could rarely be certainty about suicidal intent being the sole cause of an accident,” Dr. Vuorio told The Hindu in an email.
Disagreements Among Investigators
In a recent academic review of four fatal crashes suspected to be pilot-assisted suicides, researchers found that national investigative bodies did not always agree with the U.S. National Transportation Safety Board (NTSB). In two of the four cases, American and local investigators disagreed on whether the pilot deliberately crashed the plane. In three of the four cases, the pilot was alone in the cockpit and the co-pilot had no access to regain control during critical moments.
Case 1: Silk Air Flight 185 (Indonesia, 1997)
The first case often cited in this category is the crash of Silk Air Flight 185 in December 1997. The Boeing 737, flying from Jakarta to Singapore, suddenly nose-dived from 35,000 feet into the Musi River in Sumatra, killing all 104 on board.
After three years of investigation, Indonesia’s National Transportation Safety Committee (NTSC) said it could not find any technical reason for the crash. But the U.S. NTSB disagreed. Their report concluded there was no mechanical failure and stated the most likely cause was intentional pilot action.
They also pointed to the captain’s personal financial problems as a possible trigger. However, there was no evidence of strange behaviour from him before the flight, making the conclusions controversial.
Case 2: EgyptAir Flight 990 (USA, 1999)
Another debated case is EgyptAir Flight 990, which crashed into the Atlantic Ocean on October 31, 1999. The Boeing 767 had taken off from New York for Cairo. About 30 minutes into the flight, the captain left the cockpit, leaving the first officer alone.
According to the flight data recorder (FDR), the first officer then manually disengaged the autopilot and pushed the plane into a rapid dive. The cockpit voice recorder (CVR) captured him repeatedly saying, “I rely on God,” in Arabic, moments before the plane plunged.
The NTSB concluded that the crash happened because of the first officer’s actions, though they couldn’t confirm why. The Egyptian Civil Aviation Authority (ECAA), however, rejected this. They insisted the crash was due to mechanical failure and not intentional.
Case 3: Mozambique Airlines Flight 470 (Namibia, 2013)
In November 2013, Mozambique Airlines Flight 470 crashed in Namibia, killing all 33 passengers and crew. The Embraer jet had been flying from Maputo to Luanda when it suddenly lost altitude and hit the ground.
The first officer had stepped out to use the toilet. While alone, the captain reportedly set the autopilot to descend. Investigators in Mozambique and Namibia blamed the crash on the captain, calling the descent “unnatural”. However, the local pilot association rejected this conclusion, and the probe took nearly three years to complete.
Case 4: Germanwings Flight 4U9525 (France, 2015)
The most clear-cut and widely accepted case of pilot suicide is the 2015 crash of Germanwings Flight 9525. The Airbus A320, flying from Barcelona to Dusseldorf, was brought down by the first officer during the cruise phase.
When the captain left the cockpit, the first officer set the autopilot to descend. He then locked the cockpit door and refused to answer calls from air traffic control. The plane eventually crashed into the French Alps, killing all 150 people on board.
The investigation was completed in less than a year. French and German authorities concluded that the first officer had deliberately caused the crash. Evidence from his home showed that he had been struggling with mental health problems and had looked up suicide methods online before the flight. Post-mortem tests found antidepressants and sleeping pills in his system. Doctors had earlier declared him “unfit to fly”, but he had kept it hidden from the airline.
Depression and Isolation
In two of the four cases studied, the pilot had a history of clinical depression. In all four cases, the pilot was alone in the cockpit when the crash occurred.
This raises important concerns about how mental health is monitored in aviation. Yet, Dr. Vuorio says that depression alone cannot predict such rare events. “There’s no certainty that suicidal intent was the sole cause of these crashes,” he notes.
The Numbers Show How Rare These Cases Are
From 1993 to 2021, the U.S. logged 7,244 fatal accidents in general aviation (private, non-commercial flights). Only 24 — or 0.33% — were classified as aircraft-assisted suicides.
Most of these happened in very small aircraft owned by individuals or flying schools, which don’t carry black boxes like FDRs or CVRs. These limitations make it harder to analyze what happened during the final moments of such crashes.
Societal Stress and Pilot Mental Health
Some researchers have also studied how sudden changes in society might affect pilot mental health. Dr. Vuorio’s research found that aircraft suicides rose nearly four times in the U.S. in the year after the 9/11 terror attacks, compared to the average in the five years before.
He argues that large-scale economic or social stress, such as recession, layoffs, or fear of terrorism, can impact pilots psychologically. However, due to the rarity of such incidents and lack of large comparison groups, it’s difficult to study this trend in depth.
What This Means for AI-171
As the investigation into AI-171 continues, it is critical to separate speculation from evidence. A preliminary report has not confirmed any pilot wrongdoing or technical cause. Claims about sabotage of the fuel intake are still unverified.
Indian pilot unions have strongly objected to media reports suggesting the captain may have crashed the plane intentionally. Government officials have also asked for patience until the final investigation report is released.
Aviation experts say such tragedies must be examined carefully and systematically. Jumping to conclusions before gathering all facts not only harms reputations but also distracts from identifying real safety flaws that may need fixing.