PENSACOLA, Fla. (AP) _ A panel of officers began deliberating Thursday in the court-martial of a Navy rescue-swimmer instructor accused of involuntary manslaughter in the drowning of a recruit.

Petty Officer 2nd Class Michael Combe, 28, of Tempe, Ariz., was on trial for the March 2 death of Airman Recruit Lee Mirecki in a training pool at Pensacola Naval Air Station.

The 19-year-old recruit from Appleton, Wis., had panicked, climbed from the pool and shouted that he wanted to quit, but instructors shoved him back in and dunked his head under water, witnesses testified during the three-week trial.

Combe was charged with battery and conspiracy to commit battery in addition to involuntary manslaughter. If convicted, he could face up up to 3 1/2 years in prison and be dishonorably discharged.

The military judge, Newell D. Krogmann, turned the case over to the five- officer court-martial panel after closing arguments in which a civilian defense lawyer contended the system, not a Navy rescue-swimmer instructor, was to blame for the drowning.

''The system is on trial,'' argued attorney W.H.F. Wiltshire. ''Mike Combe did what he was taught and what is the custom in the Rescue Swimmer School.''

A prosecutor contended, however, that no system could have prevented the criminal acts allegedly committed by Combe and other instructors.

Defense witnesses testified reasonable force was permitted to get students who wanted to quit back into training. It was used at the discretion of instructors without written rules and regulations governing the practice, they said.

Those tactics were illegal, argued the chief prosecutor, Lt. Cmdr. Larry Wynne.

''We don't motivate people through the use of physical force,'' Wynne said. ''We don't do that with human beings. We teach. They learn.''

Combe was accused of forcing Mirecki's head under water. On the witness stand, he admitted placing Mirecki in a head hold and dunking him for three counts in an effort to get the panicked recruit to let go of a rope dividing the pool.

That effort happened minutes after Mirecki was tossed into the water and about 90 seconds before he collapsed, Combe said.

After Mirecki loosened his grip, Combe said they swam to the deep end of the pool with the recruit in a head hold applied by the instructor as part of a drill known as ''sharks and daisies.''

The now-banned exercise called for instructors to imitate panicked air crash survivors. Students were to escape from their grasp by pulling them under water. Combe said Mirecki finally completed the escape and placed him in a rescue carry just seconds before he collapsed, weakly saying, ''I can't.''

Wynne argued that water found in Mirecki's lungs indicted he must have been unconscious in the water. A Navy pathologist testified Mirecki had a phobia about being dragged under water, which triggered heart failure followed by drowning.

Wiltshire focused his argument on what happened in the month before the drowning. Mirecki, seeking to drop out of the school, went to a flight surgeon who diagnosed a probable phobia and then to a psychologist who disagreed.

Through a series of bureaucratic errors Mirecki was permitted to return to training without further medical evaluation.

Wiltshire also cited testimony that an ambulance crew failed to administer oxygen en route to the hospital where Mirecki died. Another defense target was the failure of higher ranking officials to give the school closer supervision.

''If the system is wrong, then the system should be accountable, not the low man on the totum pole,'' Wiltshire argued.

Four other instructors have received non-judicial punishment of rank reductions or fines.