Two pilots were arrested yesterday after allegedly attempting to board their flight to America while drunk.
Concerns were raised after the pair tried to pass through a staff check-in at Glasgow Airport before the 9am flight to Newark, New Jersey.
The incident came six weeks after another two pilots suspected of being over the limit were arrested at Glasgow before they took charge of a long-haul passenger flight.
The United Airlines pair are being held over the weekend at Govan police station, about five miles from the airport, reports the Sunday Mail.
It’s understood each has the rank of first officer with the airline.
A source said: “Concerns were raised and police were called.
“There was a fair police presence as it’s a sensitive and highly secure part of airport.
“Staff are subject to intensive and thorough security procedures in just the same way as passengers. No chances are taken nowadays.”
Their flight’s status was listed afterwards as “scheduled” and it eventually took off with 141 passengers on board at 6.30pm.
A police spokeswoman said yesterday: “We can confirm two men, aged 35 and 45, have been arrested and are presently detained in police custody in connection with alleged offences under the Railway and Transport Safety Act (2003) Section 93.”
The section of the act relates to “carrying out pilot function or activity while exceeding the prescribed limit of alcohol”.
Seats on the 3200-mile flight cost up to £600. United claim to have the “world’s most comprehensive global route network”.
The airline have around 87,500 employees, who work in every US state and in countries round the world.
In the incident last month, two allegedly drunk pilots were detained moments before their long-haul flight was due to leave.
Airport staff watched as police boarded the cockpit of the AirTransat plane on July 16 and removed the men.
The scheduled passenger service had been due to take off at 1pm on a seven-hour flight to Toronto, Canada.
The plane was grounded for the rest of the day while a replacement crew were arranged.
Passengers were put up in hotels overnight and were put on alternative flights the next day.
The pilots were remanded in custody but freed from Low Moss prison near Glasgow a week later.
However, Jean-Francois Perreault, 39, and Imran Zafar Syed, 37, had their passports seized as a condition of bail.
Neither made a plea before the case was continued and both are due to appear again at Paisley Sheriff Court.
Perreault and Syed, from Ontario, Canada, are accused of breaching aviation alcohol limits.
Passengers on the service have been promised up to £500 compensation after they were stranded.
The flight industry has been hit by a series of pilot scandals involving alcohol recently.
Last year, a man was jailed for flying an executive jet from Spain after a three-day binge.
Ian Jennings, 48, from Gosport, Hampshire, was detained at Norwich airport after landing a chartered plane carrying millionaire Andre Serruys plus a woman and three teenage girls.
He was locked up for nine months after being found to be three times legal limit for being in charge of a plane. Last April, a pilot on American airline Jet Blue was charged with flying while drunk with 151 passengers on board.
Dennis Murphy was arrested on a charge of operating a commercial vehicle while under the influence following the flight from Orlando to New York.
Murphy was selected for random alcohol testing after landing at John F Kennedy International Airport in New York.
A month before, an American Airlines co-pilot was charged for drinking alcohol before a weekend flight out of Detroit.
And last August, an AirBaltic flight carrying 109 holidaymakers was grounded in Oslo after four of the five crew members failed alcohol tests. The co-pilot was found to be seven times over the alcohol limit and was sentenced to six months in prison.
The pilot was given 10 months behind bars, while the two flight attendants were sentenced to 45 and 60 days.
A first officer with a major airline such as United typically earns around £110,000.
Although their rank is equivalent to co-pilot and the men arrested yesterday were not captaining the aircraft, their removal left the flight without enough crew members to depart before replacements could be found.
A spokesman for United said: “The two pilots have been removed from service and their flying duties.
“We are co-operating with the authorities and will conduct our own investigation as well. The safety of our customers and crew is our highest priority.
“Our team at Glasgow Airport have provided our customers with support including meal vouchers and hotel accommodation where required.
“We apologise to our customers for the inconvenience caused.”
A spokesman for Glasgow Airport added: “We are aware of an incident whereby two crew members were arrested this morning.”
The drink-fly limit is stringent.
In the UK, it is 20 milligrammes of alcohol per 100ml of blood – less than half the new Scottish drink-drive limit of 50 mg of alcohol in every 100ml of blood.
Aviation expert Martin Greenfield said: “The dangers for air crew are the same, if not worse, as those presented by drink driving.
“It’s all about safety – this must be paramount at all times. I personally would have no sympathy with any pilot who would take a chance with their alcohol level.
“The Act under which they can be prosecuted covers various roles including a range of operational staff and engineers.
“Pilots and ground staff who fall foul through their own misjudgement face heavy sanctions both in terms of the law and their career.”