New Delhi, Aug. 18 -- Aviation safety regulator the Directorate General of Civil Aviation (DGCA) may soon ask all domestic airlines to conduct drug tests for their pilots, a move prompted by the pilot of Air India's August 4 flight testing positive for drugs, and two other Air India pilots, failing an initial drug test. "DGCA is in the process of issuing an order on drug testing that will apply across all domestic airlines, rather than being limited to Air India. "The order will be out soon," a DGCA official said, asking not to be named. Air India started drug tests for all its pilots from August 13, following the Phuket flight, which lost altitude suddenly, reportedly ion account of technical issues, injuring several passengers and crew. It later emerged that the pilot had failed a preliminary drug test; subsequently, a confirmatory test returned a positive result (for drug usage). Air India officials said that till Monday, around 400 pilots were tested, of which two failed a preliminary test....