Bottle-to-throttle: The precautions airlines take to make sure your pilot is sober

By Kate Springer, CNN

It’s widely understood that drinking and operating heavy machinery don’t mix.

Alcohol can slow reaction time, impair judgment, cause trouble focusing and lead to dizziness or nausea — effects that become even more dangerous when operating an aircraft.

And while it’s rare for commercial pilots to attempt to fly under the influence, a string of incidents in recent years has brought the issue to the forefront.

Most notably, Japan Airlines came under scrutiny due to excessive alcohol consumption by two pilots the day before their flight in December 2024.

A captain from the same airline admitted to drinking three beers the day before his flight from Hawaii to Japan’s Chubu Centrair International Airport the following August.

After failing a self-administered alcohol test, the pilot ultimately called in sick, setting off a cascade of delays as the airline rushed to find a replacement.

In the fallout, Japan Airlines dismissed the pilot, announced temporary pay cuts for senior executives and vowed to improve its safeguards.

But Japan’s flagship carrier is not alone. In January of 2024, a Southwest Airlines pilot was arrested in Savannah, Georgia, on suspicion of being under the influence before a flight to Chicago.

And last July, a Delta Air Lines flight from Stockholm to New York was canceled after a pilot’s breathalyzer test exceeded the maximum allowable blood alcohol content (BAC) of 0.02% under European Union law.

These incidents raise the question: what safeguards are actually in place to ensure pilots are sober when they get behind the flight controls?

The answer is far from clear-cut, because there’s no universal law that applies to every airline.

In practice, airlines rely on several layers of protection: bottle-to-throttle rules, strict BAC limits, random testing, suspicion-based testing, medical oversight, peer reporting systems, rehabilitation programs and — in the case of violations — severe penalties ranging from license suspensions and revocations to criminal charges. Some countries also require pre-flight breath tests.

While guidance from the International Civil Aviation Organization prohibits licensed aviation personnel from “operating under the influence of psychoactive substances,” regulators and individual airlines determine the specific details, resulting in a patchwork of rules.

Some countries require a BAC below 0.04%, while others mandate limits of 0.02% or even 0.00%.

Additionally, some jurisdictions enforce eight, 10, 12 or 24 hours of “bottle-to-throttle,” referring to the time between a pilot’s last drink and reporting for duty.

All of these different rules can make it hard for pilots to keep track of specific thresholds when flying internationally. But for retired training captain Pete Hutchison, who flew internationally with Virgin Atlantic for over 20 years, the math is pretty simple.

“I worked to a more general standard, and that is, don’t even get yourself into a situation where you’re quibbling about 0.01,” Hutchison, who goes by “Pete the Irish Pilot” on Instagram, told CNN Travel.

When he had short layovers, say, less than 24 hours, he abstained from alcohol and encouraged his crew to follow suit.

If he had a longer layover of two days or more, which he says was quite rare by the time he retired, there was slightly more wiggle room to enjoy a Tsing Tao in Hong Kong or a glass of chenin blanc in Cape Town.

“We are professional people who have worked very hard to get a commercial license… And as pilots, we still face unlimited public liability. We don’t want anyone to get hurt, or our airline or the industry to go belly up. It’s not a flying circus. It’s very serious stuff.”

Different rules for different countries

In the UK, where Hutchinson is based, pilots must stay below 0.02% BAC and are subject to random testing during ramp inspections.

The screening program was introduced in February 2022 and, though Hutchinson retired in 2023, the Belfast native says neither he nor any of his crew members were ever tested.

The United States has slightly more lenient regulations.

The FAA requires pilots to have a BAC below 0.04% — half the legal limit for driving a car — and wait at least eight hours between drinking alcohol and reporting for duty.

That’s the minimum, though. Some airlines, including Delta and United, enforce a longer, 12-hour bottle-to-throttle window.

What’s more, the Federal Aviation Administration recommends waiting 24 hours, warning that the legally required eight hours may not be sufficient to reach a legal BAC, and the effects of a hangover may hamper a pilot’s performance.

Testing adds another safeguard in the US, where alcohol screening is most often conducted randomly, under reasonable suspicion — say, triggered by a colleague, TSA personnel or supervisor — or after an accident. Positive tests result in actions including counseling, warning letters, fines, suspensions and license revocations, the FAA says.

In Japan, pilots must comply with the country’s Civil Aeronautics Act and its Enforcement Regulations, which generally prohibit flying when under the influence of alcohol, drugs or other chemical substances that can “impair in any way their ability to perform normal operations of aircraft.”

While Japanese law does not dictate specific limits, airlines are expected to implement their own standards to ensure safety and compliance.

Following the incidents in 2024 and 2025, Japan Airlines introduced a series of stricter rules and safeguards.

Among them, the airline extended the bottle-to-throttle period to 24 hours and began requiring three mandatory breathalyzer tests before every flight. In 2024, the airline also banned drinking during hotel layovers.

“Since September, we have implemented measures such as suspending flight duties for pilots assessed to have any alcohol-related risks and increased random testing, especially after overnight stays,” a spokesperson for Japan Airlines told CNN Travel.

Zero tolerance in India

India is often cited as having the world’s toughest rules when it comes to alcohol and flight.

The Director General of Civil Aviation enforces a strict zero-tolerance policy, designed to eliminate any possibility of impairment in the country’s rapidly expanding aviation industry.

For pilots, that means a 12-hour bottle-to-throttle rule and a 0.00% BAC limit.

In addition, before every flight, pilots must take a breathalyzer test on camera in a designated room at the airport.

“Even 0.001 is considered a positive result,” Captain Tarana Saxena, who flies internationally for an Indian airline, told CNN Travel. “You have to remember to do it. Otherwise, it’s considered positive, and there are heavy penalties.”

The first offence triggers a three-month suspension of the pilot’s license, a second results in a three-year suspension, while a third will lead to a permanent loss of license.

Saxena recalls a young first officer who, chatting and distracted, nearly forgot to take his breathalyzer test — sometimes known as a BA.

“We were about to close the cabin doors when the medical team called him… He just ran. If we had taken off without him doing a BA, it would have been considered a positive test.”

The rule applies to international arrivals in India as well.

“When arriving from airports without testing facilities, we must take a test immediately upon landing,” she added. “I keep sticky notes — ‘BA post flight’ — in the cockpit to help me remember.”

Although India mandates a 12-hour bottle-to-throttle rule, she says many of her colleagues voluntarily extend it to 16 or 24 hours to be safe.

They’re not only worried about any lingering traces in their system, Saxana said, but also the fact that alcohol can exacerbate fatigue and disrupt sleep, potentially impairing their performance even if they are sober.

To avoid even microscopic readings, crew members also avoid products like mouthwash, perfume or sanitizer, she said.

“I understand why it’s strict, but even a limit of 0.01% instead of 0.00% would reduce the pressure,” she added. “We have to be so careful to remember and avoid all the things you can’t do before a BA.”

Saxena, who serves on her airline’s fatigue-management safety team, is more worried about safety issues arising from demanding scheduling rosters than about drinking.

“Since I’m a health-conscious person anyway, and this job already disrupts my social life and sleep schedule, I’m not even thinking about alcohol when I’m off-duty,” she said. “I’m so tired, all I want to do is sleep.

“But whereas alcohol consumption is under my control, fatigue is out of my hands … Fatigue is a very, very big issue right now in our pilot and cabin crew community.”

Busy skies

Pre-employment drug and alcohol screenings, random testing and reasonable-suspicion checks are now common worldwide, but as noted the thresholds vary from place to place, and that can complicate things in Europe.

The European Union’s Aviation Safety Agency (EASA) has a 0.02% BAC limit like the UK, and requires airlines and aviation authorities to maintain multilayered prevention systems.

“In general, alcohol testing is performed randomly,” said EASA spokesperson Janet Northcote, who added that confirmed-positive cases are handled under national laws.

Some EU member states impose tougher rules, like Italy, which considers anything above 0.00% BAC a violation.

In Asia, the Civil Aviation Authority of Singapore (CAAS) requires an eight-hour bottle-to-throttle period and an alcohol limit of 0.02 grams per 210 liters of breath, equivalent to a 0.02% BAC.

“The CAAS has a zero tolerance policy towards alcohol consumption by pilots,” Foong Ling Huei, director (flight standards) of the Civil Aviation Authority of Singapore, wrote in a statement to CNN Travel.

In 2019, the CAAS introduced a random testing program that applies to pilots from both foreign and local carriers.

In addition, operators must have their own alcohol management programs to “proactively identify, manage and rehabilitate pilots with problematic use of alcohol,” added Foong.

Hong Kong’s Cathay Pacific also has a 10-hour bottle-to-throttle rule and a limit of 9 micrograms of alcohol in 100ml of breath, which is approximately 0.02% BAC.

The United Arab Emirates also enforces a 0.02% BAC limit with regular airport testing and tough penalties, including criminal charges and the loss of the pilot’s license.

Navigating the pressures of the job

Alongside formal rules and testing, many airlines also offer peer support and rehabilitation programs to help crew who may be struggling.

Virgin Atlantic, for example, offers an extensive range of support systems, from wellbeing resources and mental health assessments to confidential medical advice through occupational health services and on-the-spot mental health support. The airline said it follows guidance from the UK’s Civil Aviation Authority on offering pilots pathways for regaining clearance lost through alcohol related issues.

Such programs are vital, in part because pilots may be navigating pressures that go unseen.

A 2025 French study in the journal Frontiers in Public Health found notable levels of anxiety, depression and alcohol misuse among European airline pilots.

Of 1,220 respondents, over a quarter reported anxiety, 13% reported depressive symptoms and roughly 40% reported alcohol misuse, prompting calls for deeper research into causes and more robust support systems.

When a pilot is abruptly removed from an aircraft, it can make for sensational headlines.

But it’s worth keeping in mind that alcohol-related violations are exceedingly rare.

According to the FAA’s most recent alcohol testing data, 64,023 random alcohol tests were administered to safety-sensitive aviation personnel in 2023.

Of those, only 65 — or 0.001% — came back as equal to or greater than the legal limit of 0.04 BAC.

The FAA also conducts tests when there is reasonable suspicion.

Of 368 suspicion-based tests, 149 were confirmed positive, and those individuals were removed from duty and required to complete the FAA’s return-to-duty process.

The process includes an evaluation, recommended education, potential rehabilitation, follow-ups, a return-to-duty test and ongoing negative drug and alcohol tests.

Hutchison, the former commercial pilot, said alcohol-related incidents were exceedingly rare during his 40 years of flying.

“Now, not everybody gets it right, and I’m not defending them,” he said. “But if you load up your Flightradar24 app and zoom out, it’s like a beehive — there are airplanes everywhere.” Incidents, he added, “are not even a breadcrumb in the Atlantic Ocean.”

Alcohol-linked accidents have occurred — notably a Japan Airlines cargo crash in 1977 and an Aeroflot-Nord crash in 2008 — but such cases are outliers.

“Air travel is the safest mode of travel… and that safety is not an accident,” Hutchison says. “It’s through rigorous training, maintenance of standards, and learning from incidents over the years.”

In addition to regular alcohol and drug testing, pilots also undergo full simulator checks every six months, during which their license is temporarily suspended until they pass.

“No surgeon, nurse, lawyer, vet or senator faces that kind of continual scrutiny,” he says. “There’s no other job like it.”

And while the system is not standardized globally, nor is it perfect, multiple layers of protection — rules, testing, training, peer oversight and self-reporting — typically catch impairment long before an aircraft leaves the ground.

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