India, Sept. 4 -- The pilot-in-command (PIC) of the August 4 Phuket-Delhi Air India flight, which suffered a sudden loss of altitude during cruise and left 20 passengers and four crew members injured, tested "non-negative" for a psychoactive substance in a confirmatory test, a preliminary Aircraft Accident Investigation Bureau (AAIB) report released on Friday said. The Airbus A320neo with 137 passengers suffered an "altitude upset" after losing all three hydraulic systems within seconds while cruising at 36,000 feet, the agency found.

The report said the PIC was the pilot monitoring, or crew member in a two-pilot aircraft not actively handling the primary controls, and the copilot tested negative in both tests. It did not establish any l...