When a pilot returns a "non-negative" drug test, a chain of safety rules snaps into action almost immediately — and the pilot doesn't get to keep flying while it plays out. India began testing its cockpit and control-room staff for drugs on 31 January 2022. The regulator, the DGCA, ordered every scheduled airline to run random drug tests on flight crew and air traffic controllers, and to cover at least 10% of them each year. The rules sit in a document called the Civil Aviation Requirement (CAR), Section 5, Series F, Part V. Beyond random checks, airlines must also test people before hiring them, after an accident, and as follow-ups on earlier cases. The test itself uses a urine sample, split into two sealed bottles labelled A and B. It screens for a wide list of substances — amphetamine, methamphetamine, cannabis, cocaine, opioids, barbiturates, benzodiazepines and ecstasy, among others. So what actually happens once a pilot is flagged? The process is deliberately cautious — remove first, verify later. The test: A urine sample is taken and split into two sealed bottles, marked A and B. First screening: If this initial screen comes back "non-negative," the pilot is pulled off flying duty at once — before anything is confirmed. Grounded first, questions later: This is the heart of the safety net. A suspected risk is taken out of the cockpit immediately. It is exactly why both pilots of the Phuket-Delhi flight were de-rostered while testing continued. The confirmatory test: The second bottle (B) goes to a DGCA-authorised laboratory. The sample's temperature and chain of custody are protected at every step, and the lab reports directly to the DGCA's Director of Air Safety. Only this test decides: A screening flag is not a verdict. Only the lab's confirmatory test can prove a banned substance is actually present. First time: the pilot is sent to a de-addiction and rehabilitation centre, and can fly again only after being medically cleared. Second time: the flying licence is suspended for three years. Third time: the licence is cancelled — effectively ending the career. Every time: the case must be reported to the DGCA within 24 hours. Alcohol has its own, older rulebook. Under Rule 24 of the Aircraft Rules, 1937, and the DGCA's alcohol-testing requirement — updated to Revision 5 on 9 February 2026 — crew are barred from drinking within 12 hours of a flight and are breath-tested before duty. Here, India runs an effectively zero-tolerance line: any detectable alcohol grounds the pilot. The design is deliberate. A pilot who is impaired can put hundreds of lives at risk in seconds, so the rules are built to pull even a suspected risk from the cockpit instantly, then verify carefully before deciding a person's fate. The trade-off is that an innocent pilot can be grounded on a preliminary flag — which is why the confirmatory test, and the presumption of innocence until it lands, matter so much.