New Delhi, Sept. 5 -- The Aircraft Accident Investigation Bureau (AAIB) has found that the pilot-in-command of an Air India flight from Phuket to Delhi tested positive for a psychoactive substance in a confirmatory test and has recommended that the Directorate General of Civil Aviation (DGCA) take "appropriate action" on priority. The preliminary report does not link the pilot's psychoactive-substance test result to the altitude upset or establish the cause of the hydraulic-system disruption yet. The August 4 incident involved Air India flight AI2379, an Airbus A320-251N carrying 145 people. The flight lost pressure in all three hydraulic systems while cruising at 36,000 feet, gained 372 feet and then fell 292 feet, injuring 24 people, the report said. AAIB has not stated the cause of the loss of hydraulic pressure. AIBB does not name the substance or the pilot but uses the regulatory term "non-negative" in its report to describe the pilot's test. "In this case, it has been observed that the PIC (pilot in command) was found non-negative for psycho-active substance in the confirmatory test," the report said. "The confirmation of use of psycho-active substances is a serious concern and AAIB recommends appropriate actions by DGCA on priority." Both pilots underwent breath-analyser tests after landing in Delhi. They were subsequently tested for psychoactive substances. The pilot-in-command's initial test was non-negative, following which blood samples of both pilots were sent to a laboratory for confirmation. The co-pilot tested negative in both tests. Under DGCA rules, a first confirmed case of psychoactive-substance use does not automatically mean cancellation or suspension of a licence. The pilot is required to undergo rehabilitation or de-addiction and can return to flying only after completing the prescribed process....