All Nippon Airways Co. said Tuesday an internal probe had found that last week one of its pilots caused domestic flight delays after drinking alcohol before flight duties despite the company's 12-hour ban, and that he also asked a co-pilot to lie about it.

The case, which occurred at subsidiary ANA Wings Co., follows decisions by the government and Japanese airlines to tighten controls on drinking by staff after a Japan Airlines Co. pilot was convicted of heavy drinking in the U.K. that delayed a London-Tokyo flight.

The two pilots were scheduled to fly from Osaka to Miyazaki at 7:10 a.m. on Thursday last week, but the pilot drank beer and other alcoholic beverages at an Osaka restaurant until around 9:30 p.m. the day before, according to the company. The co-pilot stopped drinking around 7 p.m. but stayed at the restaurant with the pilot, according to All Nippon Airways.

A Breathalyzer test before the flight found the pilot had a higher-than-permissible level of alcohol and had to be replaced. The problem caused delays to five flights and affected a total of 677 passengers.

The two initially said during the airline's probe that they only drank until around 7 p.m. the day before.

ANA Wings had another alcohol-linked flight delay in October when a pilot became ill from drinking. The transport ministry issued a warning to the company in December, along with three other airlines, while JAL was issued with a business improvement order over the U.K. incident.