Claims of Air India Pilot’s Marijuana Use: Key Unanswered Questions in the Investigation
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Investigators were surprised by reports that an Air India pilot tested positive for marijuana consumption after a flight.
However, the test results have yet to be officially confirmed, and even if confirmed, they might not be definitive evidence.
On August 4, an Air India Airbus A320 flight from Phuket, Thailand, to Delhi experienced a sudden altitude drop of about 300 feet, injuring 13 passengers and four crew members.
The aircraft, carrying a total of 137 passengers and eight crew members, landed safely in Delhi. The investigation into this flight is ongoing.
India’s Ministry of Civil Aviation has stated that both pilots underwent routine post-flight drug testing.
The ministry noted that while the captain’s initial test indicated marijuana use, a second test was necessary for confirmation, and both pilots have been grounded until the investigation concludes.
Some media outlets, citing sources, claimed the second test confirmed the captain had consumed marijuana, although Air India has not confirmed this.
This report has sparked widespread debate in India about pilot drug testing and aviation safety.
So far, no clear link has been established between the sudden decrease in altitude and the pilot’s drug test results.
Investigators are examining the incident from multiple angles, including technical factors, operational issues, and human and health aspects.
Naturally, the question remains whether marijuana use played a role.
Another important question is what the pilot’s mental condition was in the hours before the flight, given the evidence of marijuana use.
What Studies Reveal About the Effects of Marijuana
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Many studies have explored how marijuana affects complex task performance.
But reliable data on immediate performance after consumption is scarce.
One early study in 1976 had 10 pilots consume small amounts of marijuana before flying flight simulators.
The research found increased errors in altitude control, navigation, and radio communication.
These effects lasted at least two hours and typically subsided after four to six hours.
A decade later, researchers examined any residual effects after the main influence of marijuana had worn off.
Ten experienced private pilots flew simulators 24 hours after consuming marijuana.
They exhibited diminished ability in landing, instrument control, and flight path adherence, despite being unaware of their impaired performance.
A follow-up study in 1991 reached similar conclusions.
Testing pilots 15 minutes, 4, 8, and 24 hours after smoking marijuana-laced cigarettes showed degraded performance.
Even 24 hours after consumption, seven of nine pilots showed some impairment, but only one was aware of the effect.
However, these studies are old and based on small samples, making it difficult to draw firm conclusions.
Additionally, these experiments used simulators rather than modern aircraft, limiting their applicability to the Air India cockpit incident.
Still, experts agree these studies show marijuana can impair concentration and task performance critical for flying.
A review by aviation medical expert David Newman from Australia’s Transport Safety Bureau supports these findings.
The impact of marijuana on behavior, cognition, and psychological functions varies with dose.
Complex activities like flying are especially sensitive, with effects possibly lasting up to 24 hours.
As marijuana use becomes more widespread globally, its effects grow increasingly complex to assess.
How Long Do Marijuana’s Effects Last?
A 2022 study led by Thomas Marcotte at the University of California examined 191 regular users and found that their work performance was initially impaired after marijuana use.
However, performance nearly matched non-users’ levels about four and a half hours later.
This finding is highly relevant for aviation testing protocols.
In some cases, marijuana metabolites can be detected in blood for weeks, particularly in regular users, but impairment generally lasts three to five hours.
Edible marijuana products can produce longer-lasting effects than smoking.
Studies show effects from ingested marijuana typically last six to eight hours or longer.
Consequently, there is no globally accepted standard for marijuana testing protocols.
After legalizing recreational marijuana, Canada implemented strict rules requiring aviation staff and air traffic controllers to abstain from marijuana at least 28 days before duty.
This is due to the uncertainty about marijuana’s effects, according to Canadian regulators.
A 2026 U.S. National Transportation Safety Board study found that 52% of deceased pilots from aviation accidents between 2018 and 2022 had used some form of drugs.
However, the study did not assess the impact of drug use on pilots’ performance.
Even when marijuana metabolites are found in blood, it is challenging to definitively link them as direct causes of accidents.
Additional Research Raises Important Questions
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Researchers have further pursued questions related to this topic.
Following a 2011 Canadian plane crash, investigators found 50.1 nanograms per milliliter of marijuana metabolites in the pilot’s blood.
Canada’s transportation safety agency stated this level could affect the pilot’s flight planning and abilities, though contradictory findings also exist.
In 2017, a New Zealand helicopter crash investigation revealed that the pilot had consumed marijuana two days prior.
However, forensic analysis found no link between marijuana effects and the crash.
Studies emphasize that the presence of marijuana in blood does not always imply impairment.
In the Air India case, investigators must confirm marijuana evidence with the second test and determine the timing of consumption from the sample.
Air India will need to expand drug testing beyond its current 10% of pilots to ensure broader safety coverage.
According to Marcotte, marijuana can be detected in urine, blood, and saliva, but determining when it was last used is challenging.
Saliva testing can detect use within a few hours prior to sampling.
Experts note that simply confirming marijuana use does not answer all questions.
Key inquiries focus on whether marijuana was used, if impairment was present during the flight, and whether it contributed to the sudden altitude loss.
While the first question may be answered relatively quickly, the latter two remain complex and difficult to resolve.
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