India, Sept. 4 -- A preliminary report in the turbulence incident on an Air India flight from Phuket to Delhi has revealed that the pilot tested 'non-negative' for psycho-active substance in the confirmatory test. HT had earlier reported about the pilot testing positive for Marijuana after his preliminary drug test returned "non-negative".

"The confirmation of use of psycho-active substance is a serious concern and AAIB recommends appropriate actions by DGCA on priority," the latest report said.

A detailed investigation in the matter is underway. The final report will be published in due course, it said.

On August 4, flight AI2379 from Phuket to Delhi dropped 300 feet in a sudden loss of altitude during cruise, injuring 20 passengers a...