Flight deck of an Airbus A320 after landing at night

Pilot Alcohol Rules: Bottle to Throttle and the Real Limits in the US, UK and EU

by Connor Kerr | Sep 27, 2026 | Mundo de la aviación | 0 comments

Every pilot learns the phrase in their first few hours of ground school: eight hours bottle to throttle. It sounds simple. It is also only the beginning of the rules, and plenty of pilots who think they know them have been caught out, sometimes in handcuffs at the aircraft door.

Alcohol limits for pilots are among the strictest of any profession, and they differ from country to country. Here is what the rules actually say in the United States, the United Kingdom and Europe, how testing works, and what happens to pilots who get it wrong.

Datos rápidos

USA (FAA): No flying within 8 hours of drinking, or with an alcohol concentration of 0.04 or more (14 CFR 91.17)
UK: 20 mg of alcohol per 100 ml of blood, or 9 micrograms per 100 ml of breath (Railways and Transport Safety Act 2003)
EU (EASA): 0.2 g/l in blood, or 0.1 mg/l in breath, above which a crew member is considered impaired
EU testing: Random alcohol testing of flight and cabin crew under Regulation (EU) 2018/1042, in force since 14 February 2021
Bottle to throttle: A minimum, not a guarantee: a pilot can still be over the limit after 8 hours
Penalties: Removal from duty, licence action, and in the UK a prison sentence

The FAA Rule: Eight Hours and 0.04

In the United States the core rule is Federal Aviation Regulation 91.17. It applies to every crewmember of a civil aircraft, from a private pilot in a Cessna to an airline captain.

“No person may act or attempt to act as a crewmember of a civil aircraft... Within 8 hours after the consumption of any alcoholic beverage... While under the influence of alcohol... While having an alcohol concentration of 0.04 or greater in a blood or breath specimen.”

14 CFR 91.17(a) — US Federal Aviation Regulations

Note the word or. Eight hours after a drink, a pilot can still be under the influence or above 0.04, and then they cannot fly. That is why many airlines set their own rules stricter still. According to Aerospace Global News, US testing programmes also treat a breath result between 0.02 and 0.039 as a temporary stand-down from safety-sensitive duty, and airline pilots are subject to random, reasonable-suspicion and post-accident testing.

The UK: a Limit Four Times Lower Than for Driving

The United Kingdom is stricter still. Under the Railways and Transport Safety Act 2003, the prescribed limit for aviation functions is 20 milligrams of alcohol per 100 millilitres of blood, 9 micrograms per 100 millilitres of breath, or 27 milligrams per 100 millilitres of urine. For comparison, the drink-drive limit in England and Wales is 80 milligrams per 100 millilitres of blood.

Being over the limit is a criminal offence. In June 2023, Delta Air Lines captain Lawrence Russell was stopped before a flight from Edinburgh to New York. His blood test showed 49 milligrams per 100 millilitres, well over twice the limit. In March 2024 he was jailed for 10 months.

Delta Air Lines Boeing 767 at Edinburgh Airport — A Delta Air Lines Boeing 767-300ER at Edinburgh Airport. In 2023 a Delta captain was arrested before a flight from Edinburgh to New York and later jailed for being over the UK aviation alcohol limit. Photo: Wikimedia Commons, CC BY 4.0

“This conviction should send the message that crimes of this nature will be robustly dealt with.”

Lynne Barrie — Procurator Fiscal for Lothian and Borders, Crown Office and Procurator Fiscal Service, March 2024

The Delta pilot sentenced to 10 months in Scotland for being over the alcohol limit before a flight. Video: 11Alive

Europe: 0.2 Per Mille and Random Tests

In the European Union, Regulation (EU) 2018/1042 introduced alcohol testing for flight and cabin crew, in force since 14 February 2021. According to Austro Control, Austria's aviation authority, a breath alcohol level above 0.1 milligrams per litre, equivalent to 0.2 grams per litre in blood, means a crew member is considered impaired. National inspectors carry out random tests during ramp inspections.

A positive result, or a refusal to be tested, takes the crew member off duty immediately. The result goes into the EASA ramp inspection database without personal details, other states and the operator are informed, and licensing and administrative penalties can follow. Some countries go further: Italy, according to Aerospace Global News, applies zero tolerance.

Alcohol breath analyzer demonstration — A US Department of Transportation researcher demonstrates an early alcohol breath analyzer. Breath testing on the same principle is now used to check pilots and cabin crew. US National Archives / Wikimedia Commons, public domain

Why the Rules Are So Strict

Alcohol slows reaction time and degrades judgement and coordination, the abilities a pilot most needs when something goes wrong. Aviation regulators have chosen limits close to zero because the margin for error in a cockpit is small.

Cases still happen. On 6 September 2026 an Air India first officer was removed from flight AI 151 from Zurich to Delhi shortly before departure after failing a preliminary breath test, according to The Statesman. The airline suspended him and the flight operated the following day. It is a reminder that the system of testing and reporting works precisely because it catches people.

A flight instructor explains the alcohol rules every pilot needs to know. Video: wifiCFI

The simplest rule is the one many pilots adopt for themselves: if there is any doubt, do not fly. Eight hours is the legal minimum, not a target.

News coverage of the Delta pilot's arrest in Scotland in 2023. Video: 11Alive

Sources: eCFR (14 CFR 91.17), legislation.gov.uk (Railways and Transport Safety Act 2003), Austro Control, Crown Office and Procurator Fiscal Service, Aerospace Global News, The Statesman

Preguntas frecuentes

What is the bottle to throttle rule for pilots?

The bottle to throttle rule is the FAA requirement in 14 CFR 91.17 that no one may act as a crewmember of a civil aircraft within 8 hours of drinking alcohol. It is only a minimum: pilots are also prohibited from flying while under the influence or with an alcohol concentration of 0.04 or more.

What is the legal alcohol limit for pilots in the US?

Under FAA rule 14 CFR 91.17, a pilot may not fly with an alcohol concentration of 0.04 or greater in a blood or breath specimen, within 8 hours of drinking, or while under the influence. US testing programmes also treat 0.02 to 0.039 as a temporary stand-down from safety-sensitive duties.

What is the alcohol limit for pilots in the UK?

Under the Railways and Transport Safety Act 2003, the UK limit for aviation functions is 20 milligrams of alcohol per 100 millilitres of blood, 9 micrograms per 100 millilitres of breath or 27 milligrams per 100 millilitres of urine. Exceeding it is a criminal offence.

What is the EASA alcohol limit for pilots?

In the European Union, a flight or cabin crew member with a breath alcohol level above 0.1 milligrams per litre, equivalent to 0.2 grams per litre in blood, is considered impaired. Random alcohol testing has applied under Regulation (EU) 2018/1042 since 14 February 2021.

Are pilots randomly tested for alcohol?

Yes. US airline pilots are subject to random, reasonable-suspicion and post-accident alcohol testing, and in the EU national inspectors carry out random alcohol tests on flight and cabin crew during ramp inspections. Refusing a test in the EU also removes the crew member from duty.

What happens to a pilot who fails an alcohol test?

A pilot who fails an alcohol test is removed from duty immediately and can face licence action and employer discipline. In the UK it is a crime: in 2024 a Delta Air Lines captain was jailed for 10 months after testing at more than twice the limit before a flight from Edinburgh.