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Marijuana may be legal abroad, but Indian pilots face stricter rules. Here’s how crew are tested and why cannabis is harder to detect than alcohol
The pilot-in-command of Air India flight AI 2379, which flew from Phuket to Delhi on August 4, failed a confirmatory drug test for marijuana. (AI-Generated Image)
Imagine an Indian pilot on a layover in Thailand. He is off duty, the next flight is hours away, and marijuana is legal where he is. Can he use it? The answer is no; at least not if he wants to remain on the right side of India’s aviation rules. For airline pilots, what is legal for a tourist can still be a career-ending violation.
The distinction is now under scrutiny after the pilot-in-command of an Air India Phuket-Delhi flight reportedly tested positive for marijuana in a confirmatory drug test, sources told CNN-News18. The test result has raised questions about India’s rules for airline crew, how drug testing works and, crucially, whether a positive cannabis test can actually establish that a pilot was impaired while flying.
Unlike alcohol, marijuana leaves investigators with a more complicated trail. A test can detect cannabis or its metabolites long after the immediate effects have worn off, making it far harder to answer the most important question in aviation: was the pilot actually impaired at the time they were flying?
What Happened On The Phuket-Delhi Flight?
The pilot-in-command of Air India flight AI 2379, which flew from Phuket to Delhi on August 4, failed a confirmatory drug test for marijuana, sources said, adding that the pilot had initially returned a “non-negative” screening result and was subsequently subjected to confirmatory testing.
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The incident came after the Airbus A320 experienced a sudden loss of altitude by around 300 feet and briefly entered a negative-G condition. The Aircraft Accident Investigation Bureau (AAIB) said 20 passengers and four cabin crew members sustained injuries in the incident.
That brings to the focus a crucial question — If marijuana is legal abroad, can an Indian pilot use it?
The Rules
A pilot’s obligation is not determined simply by the drug laws of the country where he or she happens to be.
India’s Civil Aviation Requirement (CAR) on psychoactive substances requires scheduled commercial operators to conduct random drug testing of flight crew members. The framework was issued specifically to identify aviation personnel using psychoactive substances and prescribe action against them.
The testing panel expressly includes cannabis (marijuana) as THC. So, an Indian pilot who consumes marijuana legally in a foreign jurisdiction can still face consequences under the rules governing Indian aviation personnel.
The same principle exists in the US. Even though marijuana is legal for recreational or medical use in some US states, the US Department of Transportation says its safety-sensitive employees, including pilots, remain subject to federal drug-testing rules. State recreational or medical-marijuana laws do not make marijuana use acceptable for DOT-regulated safety-sensitive employees.
What Exactly Does India Test For?
India’s aviation drug-testing system does not simply look for whether someone “looks high”. It uses biological samples to detect specified substances.
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The DGCA framework covers six categories—Amphetamine and amphetamine-type stimulants, opiates and metabolites, cannabis/THC, cocaine, barbiturates, and benzodiazepines.
Urine is used for the testing process. The sample is divided into two containers: one is used for the initial screening and the other is preserved for confirmatory testing if the first test is non-negative.
If the screening test is non-negative, the pilot is removed from flying duty while the confirmatory test is conducted at a designated laboratory using high-complexity techniques such as gas chromatography/mass spectrometry (GC/MS) or liquid chromatography-mass spectrometry (LC-MS).
This distinction is important because a screening result is not the final determination of drug use.
How Often Are Pilots Tested?
The Indian framework provides for random testing of flight crew and air traffic controllers.
The programme is designed to cover at least 10 per cent of employees of an organisation in a year, in addition to testing in specific circumstances such as before employment, before admission of trainee pilots to flying schools and follow-up testing of confirmed cases.
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The rules also envisage testing when aviation personnel refuse a drug test by a foreign regulator during operations to that country. So international operations do not mean that an Indian crew member operates outside the reach of the Indian system.
What Happens Before Every Flight?
For Indian scheduled airlines, flight crew and cabin crew undergo a pre-flight breathalyser (BA) test for alcohol at the first departure airport during a flight duty period. This is not a cannabis test. The DGCA’s rules specifically prescribe the pre-flight breathalyser examination.
For flights originating outside India, crew undergo a post-flight breathalyser test at the first Indian airport they land at. So, an international crew member arriving in India is tested for alcohol after the flight, rather than necessarily undergoing an alcohol test before departure abroad.
What About Marijuana And Other Drugs?
That’s a separate drug-testing regime. The DGCA requires scheduled commercial operators to conduct random testing for psychoactive substances, including cannabis/THC, among flight crew and other specified aviation personnel. The programme is designed to cover at least 10 per cent of employees in a year, rather than testing everyone before every flight.
This is precisely why the Air India Phuket case is interesting: the pilot wasn’t necessarily subjected to a routine pre-flight marijuana test. The reported testing occurred after the flight, as part of the investigation/protocol following the incident. Reuters reported that the captain’s initial screening indicated the presence of psychoactive substances and that a confirmatory laboratory test was subsequently conducted.
What Happens If A Pilot Tests Positive?
A non-negative screening test is not automatically treated as drug abuse.
Once a confirmatory test is positive, the organisation’s medical in-charge consults a Medical Review Officer (MRO) to determine whether there could be a legitimate therapeutic explanation or another innocuous source. This matters because some medicines can contain substances that fall within the testing panel. For example, the medicines containing codeine can produce an opiate-positive result.
The Airline Pilots’ Association of India has also warned pilots about self-medication because some common cold, cough, allergy and sleep-aid medicines can contain ingredients covered by the testing panel.
If the MRO determines that it is a genuine case of drug use, the consequences escalate:
First positive: rehabilitation/de-addiction programme, followed by a new test and fitness certification before returning to active duty.
Second positive after returning to duty: licence suspension for three years.
Third positive: licence cancellation.
Refusing a test can also trigger penalties, including licence suspension and, for repeated violations, cancellation.
Why Is Marijuana Harder To Detect Than Alcohol?
Alcohol testing and cannabis testing answer very different questions. A breathalyser can measure alcohol in a person’s breath and provide a relatively direct estimate of blood alcohol concentration. That makes it possible to connect the measurement with established alcohol-impairment thresholds.
Cannabis does not offer the same straightforward relationship. The CDC’s National Institute for Occupational Safety and Health says cannabis can remain detectable for days or weeks after consumption, even after physiological effects and impairment have ended. It also notes that a positive urine test does not establish when cannabis was consumed or whether the person is currently impaired.
This is perhaps the biggest difference between alcohol and cannabis testing. THC is stored in body fat and its metabolites can remain detectable long after the intoxicating effects have worn off.
The CDC has noted that urine cannabinoid testing detects a THC metabolite and that urine concentration cannot reliably establish either the time of consumption or the degree of impairment.
That creates a difficult scientific problem: A urine test can tell investigators that cannabis exposure occurred. It is much harder for the test alone to tell them exactly when it occurred or whether the person was impaired at the moment of testing. This is why cannabis is more difficult than alcohol when the question is not merely “Was this substance used?” but “Was this person impaired at this exact time?”
Why Can’t Scientists Simply Use A THC Number Like A Blood-Alcohol Number?
Because THC concentration does not have the same predictable relationship with impairment that alcohol concentration has.
The US National Highway Traffic Safety Administration says there is no equivalent chemical test for marijuana impairment that works like a BAC or breath-alcohol test. It notes that THC levels do not correlate well enough with impairment to provide a comparable standard.
NHTSA also says there is little evidence for a direct dose-response relationship between blood THC concentration and impairment comparable to alcohol.
The problem becomes even more complicated because people metabolise cannabis differently, and frequency of use, route of consumption and individual tolerance can affect the relationship between THC levels and impairment.
Does That Mean A Positive Marijuana Test Is Meaningless?
A urine test may not establish current impairment, but aviation regulators are not necessarily trying to answer only that question.
For a safety-sensitive profession, the regulatory question can also be whether the individual has used a prohibited psychoactive substance at all.
India’s system therefore uses screening followed by confirmatory testing and an MRO review. The objective is not simply to determine whether a pilot is “high” at the moment the sample is collected, but to identify prohibited substance use while allowing legitimate medical explanations to be examined.
That is also why the US DOT continues to prohibit marijuana use by safety-sensitive employees even where state law permits recreational or medical marijuana.
What About CBD?
The UK Civil Aviation Authority says cannabis, including CBD derivatives, is incompatible with pilot medical certification. It specifically warns that CBD products can contain THC or other psychoactive compounds and potentially produce a positive drug-screening result.
The US DOT similarly warns that CBD products can contain THC and says safety-sensitive employees subject to its drug-testing rules should not assume CBD products are risk-free.
For an airline pilot, therefore, “It was only CBD” is not necessarily a defence to a positive result.
What Do Other Countries Do?
United States: The US Department of Transportation explicitly includes pilots among safety-sensitive employees subject to drug testing. Marijuana remains prohibited for these employees even amid changes in broader US marijuana policy. In 2026, the minimum random testing rates are 25 per cent for safety-sensitive drug testing and 10 per cent for alcohol testing in covered aviation employees.
United Kingdom: The UK Civil Aviation Authority treats drug misuse as incompatible with pilot fitness. Its guidance says applicants with disorders arising from alcohol or psychoactive-substance misuse should be assessed as unfit, while cannabis and CBD use are not compatible with medical certification.
India: India’s DGCA framework specifically identifies cannabis/THC as a prohibited psychoactive substance for aviation testing and provides a testing, confirmation, rehabilitation and disciplinary framework.
The details differ between jurisdictions, but the underlying logic is similar: a pilot is held to a higher safety standard than an ordinary consumer.
Legality Vs Fitness To Fly
The Phuket episode brings two separate questions together, but they should not be confused.
Question 1: Was marijuana legal where the pilot was staying?
That depends on the local law and, in the case of a foreign destination, on the rules of that jurisdiction.
Question 2: Could an Indian commercial pilot use marijuana and still comply with aviation regulations?
The answer is no. India’s aviation drug-testing framework expressly includes cannabis/THC.
Question 3: Does a positive cannabis test prove the pilot was impaired while flying?
That is scientifically more complicated. A urine-positive result can establish exposure/use but does not, by itself, establish the precise time of consumption or current impairment.
That distinction will be especially important in the Air India investigation. A confirmed drug-test result is a serious regulatory matter, but determining whether and how substance use contributed to an aircraft event requires a separate examination of operational, medical, technical and human-factor evidence.
About the Author
Apoorva Misra is a News Editor at News18.com with a keen interest in politics and current affairs. She loves uncovering fresh angles and telling stories through long-form features and explainers. Foll…Read More
August 12, 2026, 12:47 IST
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