The pilots of at least five, and possibly as many as 22, of the Navy planes that crashed in 1979 were suffering hangovers, although pilots are prohibited from drinking 12 hours before a flight, the Navy said yesterday.

The figures were released after Rep. Joseph Addabbo, chairman of the House defense appropiations subcommittee, said a soon-to-be released congressional study found that alcohol contributed to 15 to 20 percent of the Navy's 128 major aircraft crashes in 1979.

The New York Democrat said he has no evidence to indicate the pilots were intoxicated or had been drinking immediately before flying. "Maybe they had been drinking the night before," he said.

The Navy confirmed that the medical reports existed, but a spokesman said, "The data is very soft." Since the bodies of many pilots involved in crashes were burned beyond recognition or lost at sea, the studies are often based on interviews about the activities of pilots over the 72 hours before a crash rather than blood samples, he said.

Two separate reports by Navy medical authories reached different conclusions about the relationship of alcohol to the 1979 crashes. One said seven crashes were definitely related to alcohol use, 12 "suggested" some connection and "another four have us wondering." The other report indicated five accidents were alcohol-related and 17 might have been.

At a hearing on drug abuse in the military, Addabbo said his subcommittee's investigation found "the equivalent of four U.S. combat infantry battalions assigned to Europe are lost because of drug abuse."

Without giving any figures, he said there is a "surprisingly high number of drug infractions and arrests at sensitive military locations." Among them "were a number of military police on physical security assignments," he said.

Finally, he said, drugs are being sent to ship crews by first class mail, which military authorities aren't allowed to inspect. However, when two ship captains implied that incoming packages would be checked, almost half were returned to the senders, he reported.