The National Transportation Safety Board asked yesterday that federal regulations be changed so that airplane pilots automatically consent to be tested for drunkenness as part of accepting their pilots' licenses.

The request grows out of the board's investigation of the incident last December when pilot Donald Kroner crashed hi light plane into the seats in Baltimore Memorial Stadium just after a sell-out crowd had dispersed after a National Football League playoff game.

It took the board five days, a court order and a search warrant to get a determination as to Kroner's blood-alcohol level from a sample taken by a hospital shortly after the crash, a board spokesman said. The test was negative.

In a letter to the regulatory Federal Aviation Administration, the board said the alcohol "is a factor in about 40" private plane accidents a year - almost all fatal. "In many instances where the pilot does survive, the board has been unable to get a blood-alcohol test," the letter said.

Automobile drivers nationwide now give "iplied consent" to be tested for drunkenness when they get their drivers' licenses. The board wants the same thing for pilots.

Kroner was convicted of reckless flying in the Baltimore incident and sentenced to two years in prison.