The report on accident of Air India Express Flight IX-812 highlighted several factors which resulted in the tragic loss of 158 lives . Limiting to the human factors alone, there were both physiological limitations of the crew and failure of crew resource management (CRM), besides organisational shortcomings.
Human Physiological Limitations: Sleep Inertia
The captain had slept off during the cruise was evident from the Cockpit Voice Recorder (CVR). There was no conversation between the pilots of the ill-fated flight for the first 1 hour and 40 minutes. There were intermittent sounds of snoring and deep breathing, attributed to the captain, suggesting deep sleep. This was heard on the available recording of 2 hours 5 minutes from the 11th minute from the start of CVR until 21st minute before the accident. The first officer had made all the radio calls, while the captain had slept for about 1 hour and 28 minutes, sufficient to lapse into deep sleep. The captain on waking up from deep slumber to prepare for the approach and landing could have been affected by ‘Sleep Inertia‘.
The first officer had briefed the captain, before initiating descent, about the weather and expected approach at Mangalore airport. The captain did not respond effectively to this, instead carried out an incomplete approach briefing. This was in contravention to the related SOP.
Moreover though the first officer “confirmed having established 10 DME arc for ILS runway 24”, the sounds recorded of the captain were of “exhaling, yawning and throat clearing” .
The first officer too had shown evidence of tiredness with recorded yawns during descent.
Sleep inertia affecting performance of the captain during the critical phase of landing was attributed as a major contributory factor in this accident . It is likely that the performance of both the pilots could have been adversely affected due to this flight operating during the ‘Window of Circadian Low‘ .
It must be added here that the captain, as per the contract had to perform 8 weeks of flying duty and 2 weeks off to his hometown (in Serbia). Prior to this flight, he had returned back to Mumbai, India, from his break on 18 May 2010, The time difference between Serbia and India is three and a half hours (daylight saving). He had reached Mangalore on 19 May 2010, allowing himself close to fifty four hours of rest, to adjust to the changing circadian rhythm. It came to light later that he was suffering from ‘some’ stomach upset and sore throat.
- Fatigued Pilots! What Happened to Flight IX-812
- Who Failed in Crash of Flight IX-812? (CRM)
- Who Failed in Crash of Flight IX-812? (Organisational Failures)
Acknowledgement Image courtesy Wikipedia