Indian investigators have released a preliminary report on an incident involving an Air India flight from Phuket to Delhi on August 4, which injured 24 passengers and crew members. The Aircraft Accident Investigation Bureau found that the aircraft's three hydraulic systems — which control essential flight functions such as steering and braking — lost pressure within four seconds. This caused the autopilot to disengage and triggered continuous alarms in the cockpit. The Airbus A330, which was cruising at 36,000 feet, first climbed 372 feet before descending to 292 feet below its normal altitude. The report did not explain the cause of the pressure loss. A stall warning during the sudden altitude changes caused chaos in the cabin, with passengers and crew being thrown against overhead bins, leading to injuries. Investigators reclassified the event as an "accident" rather than a "serious incident," emphasizing the brief but intense turbulence experienced by the 137 passengers and eight crew members aboard. Initially, Air India attributed the incident to turbulence, but investigators found no evidence of adverse weather conditions reported by the pilots or air traffic control. The Airbus is designed with three independent hydraulic systems — green, blue, and yellow — to ensure redundancy and safety in case of a failure. At the time of the incident, the first officer, a 32-year-old pilot, was in control, but the 34-year-old captain took over. Both pilots were interviewed during the investigation. The captain later tested positive for a psychoactive substance in a confirmatory drug test, though the report did not name the substance. Reuters reported that the substance was marijuana. Following the incident, the pilots were required to undergo drug screening. The captain’s initial test required a confirmatory test, as stated by India's civil aviation ministry. The report has intensified scrutiny on Air India, which is already under pressure after a June 2025 crash of one of its Boeing 787s in Ahmedabad that killed 260 people. Air India has stated it is fully cooperating with the investigation and has provided access to operational, maintenance, and technical records. In response to the incident, the airline has introduced a one-time mandatory drug test for all its pilots, going beyond current regulatory requirements. The Indian government is also considering implementing annual drug testing for all pilots, rather than the current system, which tests 10 percent of pilots each year.