When police arrested 54-year-old Charles Nicholls at the control of his plane, he was found to be six times over the legal limit for alcohol.
A breath test gave a reading of 69mcg of alcohol.
In the United Kingdom, the flying limit is 9mcg, much stricter than the 35mcg limit for driving.
A blood test following his arrest gave a reading of 125mcg of alcohol, compared with the flying limit of 20mcg.
Nicholls, a captain with Royal Brunei Airways, accepted he had drunk a “large amount” the day before but claimed he had observed the pilots’ rule of “12 hours from bottle to throttle”.
But he admitted a charge of carrying out flight preparations as captain of flight B198 to Dubai when the proportion of alcohol in his blood exceeded the prescribed limit.
The trial judge told him “You were entrusted with the safety of the crew, passengers and, of course, people on the ground who may have been affected if anything had gone wrong.”
“It is plain you had consumed a large quantity of alcohol on the previous day. That is highly irresponsible and reckless. Whilst I accept you might not have realised you were over the limit, you ought to have thought about it when it was mentioned to you before the police arrived.”
Police were informed after a security smelled alcohol as Nicholls headed for the plane to start safety checks
By the time police arrived, Nicholls had started the plane’s routine flight and passengers had begun to board.
The former air force navigator had obtained a commercial pilot’s license in the US and became a captain within four years of joining Brunei Airways.
He told police he had about four pints the night before and stopped drinking at 9.30pm, thinking any alcohol would have passed through his system by the time he would be flying.
But he admitted he’d ignored that he’d been drinking heavily at lunchtime before meeting friends and drinking again in the evening.
Nicholls was fired instantly by the airline and had little prospect of getting any work.