A Latvian co-pilot has been sentenced to six months in jail after he failed a breathalyser test before he was due to take off from Oslo airport.

The 38-year old co-pilot admitted he had drank two bottles of whisky and some beer with other crew members before the flight’s planned departure for the island of Crete with about 100 passengers on board. He was found to have a blood alcohol level seven times over the legal limit.

Two flight attendants were also sentenced to 45 and 60 days each, after they tested positive for alcohol.

But the 50-year old Latvian pilot, whose alcohol level was more than double the legal limit, has rejected some of the charges against him.

He is being held in custody and will appear before a court on 17 September. The maximum sentence is two years in jail.

“We lost control,” the co-pilot told an Oslo court earlier this week. He said the group had downed two bottles of whisky, before he began drinking beer on the night of 7 August.

He was still drinking beer at 2am, just four hours before the flight was due to take off. Norwegian police tested the crew after receiving an anonymous tip-off.

AirBaltic suspended the four crew members, following the failed breath tests and has said it is seeking their dismissal.

In the wake of the arrests, the airline launched an investigation and introduced mandatory breathalyser tests for all pilots and staff with a “safety-critical” role.

“Safety is a top priority at AirBaltic and following the situation in Oslo we have stepped up safety measures,” a spokesman said.

Aviation authorities say the number of drunken pilots turning up for work is few and far between. In 2013, 13 pilots out of more than 11,000 failed a random breath test, according to the US regulator, the Federal Aviation Administration.

Earlier this year a British pilot was jailed for nine months, after he flew an executive jet from Spain to Norwich while hungover, following a three-day drinking binge.

A spokesman for the UK regulator, the Civil Aviation Authority, said anyone with concerns about airline staff were encouraged to contact the airline, or the CAA, which runs a confidential whistle-blowing service.

The blood alcohol limit for flying is four times stricter than for driving. Flight crew and air-traffic controllers cannot work if they have 20 milligrammes of alcohol per 100 millilitres of blood, compared to an 80 mg per 100 ml limit equivalent for drivers.

The drink-flying limit was fixed in European law in the late 1980s, meaning that some countries that had previously had a zero limit, such as Germany, had to relax the rules to accommodate different drinking traditions.

During the heyday of mass commercial flying in the 1950s and 60s, Air France pilots were typically served a glass of wine with their in-flight meal.

But in recent years airlines have become even stricter on alcohol, according to Captain Tilmann Gabriel, a former airline pilot, who is now director of City University London’s aviation management programme.

During his 32-year career flying commercial planes in Europe, the United States and the Middle East, Gabriel said he had seldom heard of pilots turning up to work drunk, while attitudes to drinking before flying had become even less permissive.

“We have a very strict no-tolerance rule for any drug or dependencies,” he said. “There is probably a higher non-tolerance against colleagues who would be under the influence [than in the past].”

In theory the rules allow pilots to have a glass of wine or beer at least 12 hours before taking the controls of a plane, but Gabriel advises against any drinking before duty, especially for those flying daily short-haul flights with short breaks between duties.

“[Intoxication] varies from person to person, from constitution to constitution. You could be surprised all of a sudden to find that you have more than 0.02 [20 milligrammes] in the blood.

“I would always advise to be on the safe side on a [short-haul] rotation, to eliminate alcohol consumption.”

In the US pilots must be under a limit of 4o mg, or avoid flying eight hours after drinking alcohol – “the 8hrs from bottle to throttle” rule. However the FAA recommends avoiding alcohol 24 hours before getting into the cockpit.

Agence France-Presse contributed to this report



