History of air crash probes shows investigators disagree on pilot complicity

The Hindu

6 days ago

In two out of four fatal aircrash probes studied by academic researchers, the investigators from the national agencies disagreed with the United States National Safety Transport Board (NTSB) on whether the pilots intentionally crashed their planes.
In three of the four cases, the length of investigations averaged two-three years and in two cases the deceased pilots were proven to have a history of clinically-diagnosed depression. Three of these cases involved one of the pilots having control of the aircraft and alone in the cockpit and the co-pilots for brief periods being unable to access controls.
'Psychological autopsy' – a form of forensic investigation into the deceased's mental state – was a key factor in determining pilot intentionality and even then 'there could rarely be certainty about suicidal intent being the sole cause of an accident,' Alpo Vuorio, psychologist and an academic researcher of aviation disasters, told The Hindu in an email.
Questions on the mental health of the pilot have surfaced around the ongoing investigation into the AI-171 flight from Ahmedabad to Gatwick on June 12 where 241 passengers, including crew, died and another 19 were killed on the ground. Though only a preliminary report is out, speculation is rife that the captain may have sabotaged the plane's fuel intake during take-off. Pilot associations in India have vociferously objected to such a characterisation with Ministers advocating restraint until the investigation has concluded.
Since 1994, there have been only six confirmed instances globally involving commercial planes where investigating agencies attributed the accident to actions by the pilot. Within these, only four have published reports and analyses in academic literature. Overall, such crashes are a rarity.
Based on flying-accident reports in the United States from 1993–2021, 24 out of 7,244 – or 0.33% — fatal accident cases in general aviation were formally attributed to be 'aircraft-assisted suicides' (0.33%). The vast majority of these accidents involved pilots flying their own planes or those of very small operators where planes usually didn't carry FDR (Flight Data Recorder) and CVR (Cockpit Voice Recorder), said a 2023 study led by Dr. Vuorio in the journal Aviation Space Environment.
The first of these was Silk Air Flight 185 (Jakarta- Singapore) in December 1999, which killed 97 passengers and seven crew members. A Boeing 737, it crashed into the Musi River, Sumatra, after nose-diving from an altitude of nearly 35,000 feet. Its CVR and FDR stopped recording following which the plane rapidly descended and crashed within a minute.
Following a nearly three-year investigation, the National Transportation Safety Corporation (NTSC) – the Indonesian equivalent of India's Aircraft Accident Investigation Bureau that is investigating the Ahmedabad crash – concluded that the 'technical investigation has yielded no evidence to explain the cause of the accident.' The U.S. agency NTSB dissented. 'There was no evidence of a mechanical failure of any of the flight control systems or related components that would have been causal or contributing to the accident and the accident can be explained by intentional pilot action,' said the 140-page report. Along with a technical analysis, this report also placed on record that the captain, who had commandeered the plane, was reportedly battling a financial crisis, though it was also stated that he displayed no aberrant behaviour prior to the flight.
The second accident occurred on October 31, 1999, when Egypt Air flight 990, a Boeing 767, crashed into the Atlantic Ocean, south of Massachusetts. About 29 minutes after take-off, the FDR showed that the First Officer disconnected the autopilot. He was alone in the cockpit with the Captain having left for a bathroom break. The FDR recorded an abrupt nose-down elevator movement — the instrument meant to control the plane's pitch (up and down movement) — and the aircraft began a precipitous descent. The CVR recorded that the First Officer, a native Arabic speaker, said several times, 'I rely on God'.
After that, the FDR recorded additional unexpected movement of the aileron – a device on the tail to control a plane's rolling movements. A master warning alarm began to sound, and the Captain, who was returning from the toilet, was wondering aloud what was happening. The aircraft crashed about two minutes later. The NTSB determined that the 'probable cause was... as a result of the First Officer's flight control inputs. The reason for the First Officer's actions was not determined'. However media coverage speculated on a wide variety of causes ranging from the first officer's 'religious extremism' to alleged disputes with colleagues. The Egyptian Civil Aviation Authority (ECAA), while first collaborating with the NTSB on the investigation, concluded that 'the officer did not deliberately dive the air-plane into the ocean' and that mechanical failure was 'a plausible and likely cause of the accident'.
The third accident, on November 2013, involved the Mozambique Airlines Flight 470 from Maputo, Mozambique to Luanda, Angola. The Embraer E190 twinjet crashed into the Bwabwata National Park, Namibia, killing all 27 passengers and six crew members. About an hour and 50 minutes into the flight, the First Officer stated that he had to go to the toilet. The Captain handled the auto flight system leading to a 'sustained descent and collision with the terrain', says the investigation report. While here the investigation agencies of the Mozambique and Namibia attributed the plane's 'unnatural' descent to the pilot, the Mozambique Association of Air Operators disputed the finding. The investigation lasted three years.
The fourth analysed accident — the only one where there was rapid, unanimous consensus that a pilot, with a history of psychiatric problems, intentionally crashed the plane — occurred on March 24, 2015 with Germanwings flight 4U9525 from Barcelona, Spain to Dusseldorf, Germany. There were 150 casualties following the crash of the Airbus A-320.
According to the investigation report, in the cruise phase of the flight, the First Officer waited until he was alone in the cockpit. Then he modified the autopilot settings causing the aeroplane to descend and, kept the cockpit door locked. The First Officer did not respond to the calls from air traffic controllers, and the aircraft fell into the French Alps. One of the quickest investigations, which officially concluded within a year, the French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) and its German counterpart, the Federal Bureau of Aircraft Accident Investigation (BFU) concluded that the pilot had deliberately crashed the plane as a 'murder-suicide'. German investigators found a doctor's note in the pilot's apartment, three days following the crash, indicating that he was 'unfit to fly'. They also reported that he suffered from 'psychiatric illnesses' and a post-mortem analysis of his body found the presence of a combination of antidepressants, escitalopram and mirtazapine and a sleep medication, zopiclone. The investigation report mentioned that he had researched online ways to 'commit suicide' before commandeering the flight.
'The links between pilot suicides and social change, such as unemployment threats and financial recession, have not been studied, given the low numbers of pilot suicide cases as well as the unpredictability and infrequency of recession, coupled with methodological challenges such as suitable comparison groups and the absence of baseline measures,' said Dr. Vuorio. 'However, it has been found that significant sudden changes in society may increase the number of pilot suicides. For example, after the 9/11 terrorist attacks in New York, the risk of suicide by aircraft in the year following the attack was almost four times the average risk in the five years prior to the terrorist attack. Significant, sudden and adverse changes in society can have an impact on pilot mental health,' he added.