An Air India Airbus A320neo travelling from Phuket to Delhi lost all three of its hydraulic systems within seconds while cruising at 36,000 feet on August 4, triggering a sudden altitude upset that injured 24 people, according to a preliminary report by the Aircraft Accident Investigation Bureau (AAIB).
Flight AI 2379, carrying 137 passengers, three infants and eight crew members, was cruising normally when the flight-control system detected a loss of the green hydraulic system at 9.32:43 am IST. Within four seconds, the blue and yellow systems also failed.
The autopilot then disengaged, followed by a brief stall warning. The aircraft initially climbed 372 feet and then descended 292 feet from its assigned altitude. The sudden movement threw unbelted passengers and cabin crew against overhead bins and ceiling panels, resulting in 24 injuries.
All three hydraulic systems recovered within seconds, restoring the aircraft’s flight-control surfaces and allowing the aircraft to return to normal operation. The crew continued the flight to Delhi instead of diverting to another airport.
Technical Cause Still Under Investigation
The preliminary report has not established why all three independent hydraulic systems failed almost simultaneously or why they recovered shortly afterwards. Investigators have collected hydraulic components, fluid samples, fuel and oil samples, as well as maintenance and operational records for further analysis.
The aircraft’s flight-data and cockpit-voice recorders have also been secured by the AAIB. Technical experts appointed by Airbus and France’s aviation investigation agency inspected the aircraft following the incident.
No adverse weather was reported during the flight.
Pilot Drug-Test Finding
The report also revealed that the pilot-in-command tested “non-negative” for a psycho-active substance in a confirmatory test conducted after the aircraft landed in Delhi. The co-pilot tested negative.
However, the AAIB preliminary report did not establish any connection between the test result and the incident. It recommended that the Directorate General of Civil Aviation (DGCA) take appropriate action regarding the finding.
Air India said it would continue cooperating with the investigation and has begun voluntary testing of all its pilots as part of efforts to strengthen its safety measures.
The investigation remains ongoing, and the AAIB said a final report will be released once the inquiry is complete.
