The limit for drivers in the UK is 80 mg per 100 ml, ABC News said.
Police were alerted by the driver of a crew bus, who smelled alcohol on Jitsukawa's breath, according to NHK in Japan. The driver was taking crew members from the terminal at London's Heathrow Airport to the tarmac to board the plane.
The flight was on time, taking off with two pilots in the cockpit instead of three.
NHK reported that Japan's Transport Ministry is questioning why the airline's preflight test did not pick up alcohol on Jitsukawa's breath. Jitsukawa admitted that he drank Saturday.
The airline has a rule against drinking within 12 hours of a flight, the news agency said.
Jitsukawa pleaded guilty Thursday to a charge of exceeding the alcohol limit, ABC News reported. He remained in custody in London and was expected to be sentenced Nov. 29.