The failure of pilots to pass pre-flight alcohol tests caused delays to 16 flights operated by Japan Airlines Co. and its two group companies since April last year, a survey covering 20 major domestic airlines showed Thursday.

The questionnaire was conducted by Kyodo News following the revelation of a spate of alcohol test failures in the aviation industry, including a case that resulted in the arrest of a co-pilot. The figure does not include the case involving arrest or the latest incident at Skymark Airlines Inc. announced Wednesday.

Of the 16 flights, 12 were of JAL, three were of J-Air Corp. and one was of Japan Air Commuter Co. The remaining 17 airline operators said they had not replaced pilots due to alcohol problems.

JAL also said there were seven other cases in which pilots exceeded the alcohol limit set by the company but flights were not delayed. JAC said it had one such case.

Currently, it is left up to each company to determine measures to tackle drunken aviation staff. The latest findings could lead to calls to impose tougher regulations.

Issei Hideshima, a former chief flight attendant at JAL and a critic of the airline industry, said it is "natural" for the government to tighten regulations to bring them on par with U.S. and European standards.

Pilot replacement and additional tests resulted in delays of up to 71 minutes, according to the survey.

JAL, J-Air and JAC do not allow their pilots to board planes if they exceed the alcohol limit of 0.1 milligram per liter of breath in mandatory testing.

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All of JAL's 12 delays occurred after the carrier introduced new testing equipment last summer to crack down on alcohol problems, having pilots blow into a straw attached to a measuring device instead of breathing onto a sensor.

JAL's 12 flight delays involved eight pilots and four co-pilots whose alcohol levels ranged from 0.12 mg to 0.25 mg. Two of the flights were international services.

As for the J-Air flights, the levels of one pilot and two co-pilots were up to 0.25 mg. JAC said the levels of its two pilots exceeded the standard, but there were no detailed records.

Following additional testing, four pilots from JAL and one from J-Air were cleared to fly and carried out their scheduled duties.

JAL said earlier this month that a co-pilot was arrested by British police for being around 10 times over the legal limit under the British aviation law after he drinking the night before his London-Tokyo flight on Oct. 28. Although the flight departed more than an hour behind schedule, it was not counted among the 12 flight delays, the officials said.

That incident came to light the day after All Nippon Airways Co. apologized for flight delays in Okinawa on Oct. 25 involving five departing and arriving flights after a pilot became unwell due to drinking.

The Ministry of Land, Infrastructure, Transport and Tourism has instructed JAL and ANA to report by Nov. 16 on what measures they are taking to prevent heavy drinking by airline crew. It has also decided to hold an expert panel meeting this month to tighten drinking rules.

Skymark also said Wednesday its morning flight from Tokyo's Haneda airport to Sapporo in northern Japan was delayed for 23 minutes after alcohol was detected on the breath of the plane's American pilot.

Hideshima said he feels pilots have been given less time to rest at destinations because of increased flights in response to the growth in the number of foreign visitors to Japan.

"Stress may be encouraging heavy drinking. Just imposing strict rules is not enough. There is a need to give time to rest so that pilots can recover," he said.