Air India Phuket-Delhi flight scare: Prelim probe finds pilot positive for drugs, confirms hydraulic failure

A cascading failure of all three hydraulic systems combined with a severe altitude drop sent 24 people to medical care and triggered a probe that has now flagged a pilot for psychoactive substance abuse, a preliminary investigation report by the Aircraft Accident Investigation Bureau (AAIB) revealed.

Calling the confirmation of psychoactive substance use a "serious concern," the AAIB issued an urgent interim recommendation asking the Directorate General of Civil Aviation (DGCA) to take immediate and appropriate action to prevent the abuse of psychoactive substances among flight crews.

The flight (scheduled on August 4), AI-2379, operated by an Airbus A320-251N aircraft (VT-EXO) carrying 145 people from Phuket to Delhi, was cruising at assigned Flight Level 360 over the Kolkata Flight Information Region when its flight control systems began collapsing in rapid sequence.

At 04:02:43 UTC, the aircraft's control system detected a loss of the green hydraulic system. Four seconds later, both the blue and yellow hydraulic systems failed, stripping the aircraft of its main hydraulic pressure within a matter of seconds. The abrupt systems loss automatically disengaged the autopilot, sounded a continuous chime, and triggered a two-second stall warning.

The co-pilot, serving as the Pilot Flying, attempted to regain control before the 34-year-old Pilot-in-Command (PIC) took over. During the chaotic onset, the aircraft experienced a sudden altitude upset — climbing 372 feet before plunging 292 feet back down. Although the hydraulic systems recovered roughly ten seconds later and normal flight control surfaces were restored, the damage inside the cabin was already done.

Because seat belt signs were off during cruise, passengers and crew were violently thrown across the aircraft. Overhead ceiling panels cracked from rows 5 to 29, passenger service units were bent, emergency exit handles broke, and a lavatory commode was completely uprooted from its base.

After assessing the cabin, the crew decided against diverting to a nearby airport and continued to Delhi, requesting priority medical assistance upon landing. Upon arrival, airport medical personnel treated 24 people — 20 passengers and four cabin crew members — with four individuals suffering serious injuries that required prolonged hospitalization.

While both flight crew members passed breath-analyzer checks for alcohol upon arrival, subsequent screening using a psycho-active substance detection kit returned a non-negative result for the Pilot-In-Command. Confirmatory laboratory tests on blood samples verified the non-negative result for the captain, while the co-pilot tested negative.

Technical investigators from France's BEA and Airbus have since inspected the jet and retrieved hydraulic components and fluid samples for further lab testing at AAIB Headquarters. Flight recorders (CVR and DFDR) have been retrieved as the comprehensive investigation continues.