Air India Phuket-Delhi Flight Lost All Hydraulics at 36,000 Feet, Triggering Stall Warning and Injuries

An Air India Airbus A320 flying from Phuket to Delhi suffered a sudden loss of all three hydraulic systems mid-cruise on August 4, triggering a brief stall warning and an altitude upset that injured 24 people, a preliminary report by the Aircraft Accident Investigation Bureau (AAIB) revealed.

The AAIB, which has reportedly classified the occurrence as an ‘accident,’ noted that the seatbelt signs were switched off when the jet experienced a rapid pitch-up followed by a pitch-down, throwing passengers and cabin crew against overhead bins. The aircraft initially climbed 372 feet before dropping 292 feet from its assigned altitude of 36,000 feet.

Investigators documented extensive damage inside the cabin, including cracked ceiling panels, dislodged passenger-service-unit panels, broken handrails, detached overhead-bin doors, an uprooted lavatory commode, and a broken emergency-exit handle.

The green hydraulic system lost pressure at 04:02:43 UTC, followed four seconds later by the blue and yellow systems. The simultaneous failure disconnected the autopilot and rendered key flight controls including elevators and ailerons unresponsive for roughly four seconds.

The blue system reportedly recovered nine seconds after the initial failure, followed by the yellow and green systems, allowing the flight controls to resume normal operation. The first officer initially responded before the captain took over, subsequently flying the 137 passengers and six crew members safely to Delhi’s Indira Gandhi International Airport.

Maintenance and Pilot Drug Test Under Scrutiny

The AAIB reportedly noted that no adverse weather was reported during the flight. Prior to departure from Phuket, the aircraft had been dispatched under a Minimum Equipment List (MEL) item invoked on July 28 regarding its Power Transfer Unit (PTU) , an auxiliary power source for the green and yellow hydraulic systems. 

The investigation separately revealed that the pilot-in-command tested non-negative for psychoactive substances during post-flight medical checks, a result later confirmed by blood tests at a pathological laboratory. While the AAIB reportedly noted that the report does not establish the substance contributed to the technical failure or altitude upset, it termed the confirmation a "serious concern" and recommended regulatory intervention by the Directorate General of Civil Aviation (DGCA).

Upon landing, medical teams treated 20 people for minor injuries, while four individuals with serious injuries were admitted to hospitals.

The AAIB reportedly stated that its investigation remains ongoing to establish the probable causes without assigning blame or liability.