AI2379 commander told investigators he slept for 30-35 minutes during the Phuket-Delhi flight.
The pilot tested positive for cannabis after an initial non-negative drug screening.
The aircraft suddenly lost around 360 feet amid multiple cockpit warning messages.
Aircraft Accident Investigation Bureau (AAIB) investigators questioned the commander of Air India flight AI2379 for more than an hour after the pilot tested positive for cannabis, according to Hindustan Times.
Two people familiar with the pilot’s account told the AAIB that he had taken medication prescribed by his family doctor to manage severe sleep difficulties. The disclosure came after an initial post-flight drug test returned a non-negative result, followed by a confirmatory test that was positive for cannabis.
The Airbus A320, registered as VT-EXO, was flying from Phuket to Delhi on August 4 when it suffered a sudden loss of altitude that left several passengers injured.
The commander reportedly told investigators that he had struggled to sleep during his layover in Phuket because of personal circumstances. He did not disclose the name of the medication or how long he had been taking it.
Pilot Slept During Flight
The commander also told investigators that he slept for around 30 to 35 minutes during the flight. He was serving as the pilot monitoring while the first officer was flying the aircraft.
According to the account, the commander briefly left his seat to use the washroom before returning and standing behind the first officer as they discussed the cabin air-conditioning system.
The altitude loss occurred during this discussion, causing the commander to fall to the cockpit floor. A cabin crew member seated in the observer’s seat helped him up.
The account is the first detailed description of events inside the cockpit. However, the complete sequence could not be independently established from the pilots’ statements to investigators.
Under DGCA rules, pilots taking prescription medication are required to declare it to their airline. Non-disclosure can result in action by the operator. It remains unclear whether the commander had declared the medication.
Multiple Warnings Recorded
The aircraft’s post-flight Centralised Fault Display System log, reviewed by Hindustan Times, recorded nine warning messages within a minute at around 9.32am IST as the aircraft was flying over the Odisha coast.
The warnings included low pressure in the Green, Blue and Yellow hydraulic systems, low reservoir levels in the Yellow and Blue systems, an autopilot disconnect and an elevator flight-control fault.
Two door emergency-exit sensor warnings followed at 9.33am and 9.35am. No further hydraulic or elevator warnings were recorded for the next 43 minutes.
A separate engine anti-ice fault was logged at 10.16am, followed by another autopilot disconnect at 10.52am. Unlike the first disconnect, the second was not accompanied by hydraulic warnings.
An analysis of the log against standard A320 fault-code references suggests that the pressure readings shifted between different hydraulic-system combinations within a minute, rather than indicating a sustained failure of a single system.
Such a pattern could be consistent with a transient event, potentially involving brief movement of hydraulic fluid during the sudden altitude loss. A prolonged mechanical failure would generally be expected to produce additional or recurring warnings.
Flightradar24 tracking data places the altitude event within the same minute as the cluster of warnings. The aircraft was cruising at about 36,160 feet before the anomaly was recorded at 9.33am IST, when its altitude fell to approximately 35,800 feet , a drop of around 360 feet.
