An abnormally high dosage of prescription drugs taken by a Navy pilot might have contributed to the crash on the nuclear carrier Nimitz that killed the pilot and 13 others May 26, Rep. Joseph P. Addabbo (D-N.Y.) said yesterday.

Addabbo acknowledged in a statement that exact causes of the Nimitz tragedy and reasons for the high drug concentration in the pilot's system at the time of the crash may never be known.

Addabbo said an autopsy on Marine 1st Lt. Steve E. White, 27, found six to 11 times the recommended levels of brompheniramine, a prescription drug for which he had no prescription.

Taken in high dosages, brompheniramine is said to cause "sedation, dizziness, lassitude, nervousness, insomnia and tremors," Addabbo said.

"Investigators have determined that the pilot had no prescription for it . . . and nothing in his personal effects indicated use of the prescription drug," Addabbo said.

Addabbo cited other factors that might have contributed to the crash, such as malfunctioning center-line flasher lights on the flight deck and the pilot's concern about fuel shortage. He had been waved off on a previous attempt to land his EA6B.

Addabbo noted that autopsy reports on those killed "showed that six men had traces of illegal drugs in their systems."

The Navy acknowledged that White used an antihistamine and aspirin "sometime before his flight" but said it would be "inappropriate to speculate about the causes of the accident" until an investigation is completed.

"The antihistamine levels detected in the blood of the pilot of the aircraft were reported as being higher than the expected therapeutic range of brompheniramine," a Navy statement said.