Julian Monaghan was arrested at Gatwick on January 18 minutes before the BA flight to Mauritius was due to take off, aboard which he was scheduled to serve as first officer.
He was later charged, said Sussex Police, with performing an ancillary activity to an aviation function with 86mg of alcohol in his system per 100ml of blood. The legal limit is 20mg.
Monaghan, 49, pleaded guilty at Crawley Magistrates Court’ on June 6.
He was sentenced to eight months imprisonment when he appeared at Lewes Crown Court on Tuesday (June 12), reduced from 12 months on account of his early guilty plea.
The court heard how Monaghan, from South Africa, had drunk a glass of wine on his flight from Cape Town to Heathrow while he was a passenger.
The BBC reports he consumed “a measure” of vodka with a Diet Pepsi in his hotel room and remembered drinking three miniature bottles of vodka too.
Detective Constable Stuart Macpherson from Sussex Police said “Monaghan was reported to us through the diligence and integrity of the aircraft technician, who smelt alcohol on his breath and alerted the authorities as appropriate.
“Although he offered mitigating circumstances and was not an operating pilot on the day in question, he was still an active member of the flight deck and could have been called upon at any moment. Therefore, his mitigation does not alter the fact that he potentially put the lives of more than 200 people at risk.
“There are no laybys at 30,000ft and has Monaghan been required to take control of the aircraft in the event of an emergency on the flight deck in the early stages of the flight, his judgement and abilities would have been impaired.”
Alice Trodden, senior crown prosecutor, added: “The defendant was four times over the prescribed alcohol limit when he reported for duty as first officer for the flight.
“The defendant was arrested just 10 minutes before the flight was due to push back and the potential consequences, had he been required to take control of the plane while impaired in the event of an emergency, cannot be underestimated.
“In the face of the overwhelming evidence put forward by the police and CPS, the defendant pleaded guilty at the first available opportunity.”
Following his guilty plea, a BA spokesperson said: "This behaviour is completely unacceptable and not what we expect from our highly professional fleet of pilots.
"The safety and security of our customers and colleagues is always our top priority."