Aircraft Accident Investigation Bureau (AAIB), in its preliminary report on the August 4 Air India Delhi-Phuket flight incident, said the pilot-in-command (PIC) tested non-negative for a psychoactive substance. The AAIB flagged it as a “serious concern” and recommended that the DGCA take appropriate action on priority. On August 4, 24 passengers were injured after a momentary loss of altitude.

“Detailed investigation regarding technical and other aspects are underway. In this case, it has been observed that the PIC [pilot-in-command] was found non-negative for psychoactive substances in the confirmatory test. The confirmation of use of psychoactive substance is a serious concern, and AAIB recommends appropriate actions by DGCA on priority,” the aircraft accident probing body has concluded in its interim report.

The final report could take upto a year or more.

The report also said that during the brief loss of altitude, all three hydraulic systems had failed, the autopilot had disengaged, and the stall warning came on for two seconds. A stall warning is triggered when the aircraft can’t generate enough lift or force that keeps it up in the air.

“Initially, it gained 372 ft and fell by 292 ft from its assigned FL360 during the event” the report states about the altitude upset.

The co-pilot, who was the pilot flying (PF) responded and tried to control the prevailing situation and as the hydraulic systems recovered, aircraft operations returned to normalcy.

“At around 04:02:52 UTC, the Blue hydraulic system was recovered, and few seconds later, the Yellow hydraulic and the Green hydraulic systems were also recovered. Consequently, this led to the recovery of the Flight control [F/CTL] surfaces. Subsequently, the aircraft operation returned to its normal operating condition.”

At this time, as the aircraft was at cruising altitude and the seatbelt signs were off. That is how passengers and crew members sustained injuries, the report further notes.

The aircraft suffered damage at several points inside the cabin, including cracked or dislodged ceiling panels, bent or broken handrails, and damaged emergency exit and overhead-bin components. One of the lavatory commodes was uprooted, while a crew seat and other components near the rear doors were also damaged.