The aircraft, carrying a movie production crew, crashed for undetermined reasons, killing all 36 occupants on board.

[3] Captain Albert J. Evans (age 50) had been employed by Sierra Pacific Airlines since September 9, 1973.

[3] First officer Paul T. Dennis (age 26) had been employed by Sierra Pacific Airlines since October 15, 1973.

Dennis had been ill with the flu for the four days prior to reporting for duty on the morning of March 13.

West had occupied the jumpseat five times before the day of the accident, but had not flown into Bishop before the evening of March 13.

The crew was shooting an episode entitled "The Struggle for Survival" for the television special "Primal Man."

At 8:24 p.m., the pilots reported to Tonapah FSS that they were "climbing VFR over Bishop, awaiting clearance."

The engines were maintaining a smooth and steady sound and the plane appeared to be gradually climbing.

[3] Mike Antonio, a pilot for the Western Helicopter Company, and Dr. Dave Sheldon, a doctor, flew to the scene of the crash.

Autopsies were performed on the crew, and toxicological tests revealed no evidence of drugs, carbon monoxide, or alcohol.

There existed no specific climb-out procedures from Eastern Sierra Regional Airport in the Sierra Pacific Airlines' operation manual, but many company pilots stated that an initial right turn towards Bishop and away from the mountains was typical.

Because there was no DME equipment at the airport, pilots had to remain vigilant with these instructions to stay clear of the terrain.

The pilots carried out a VFR climb-out because of the 30 mile visibility conditions of the night, even though it was extremely dark.

[3] It is unclear why the crew decided to fly east towards the mountainous terrain instead of staying west towards the town of Bishop in the valley.

It is believed that the excellent visibility (darkness notwithstanding) created a degree of crew complacency in adherence to the distance restriction from the airport during the climb.

The first officer's previous illness, empty stomach, and fatigue may have caused his performance to be degraded.

The aircraft struck a mountain side at an elevation of 6,100 feet and 5.2 statute miles southeast of the Bishop Airport.

The captain and the first officer had flown into the Bishop Airport on several occasions within the 6-month period preceding the accident.

The first officer was most probably in a fatigued condition as a result of the after effects of the flu virus, a long duty day, and a lack of food.

Study the feasibility of an IFR climb procedure to the northwest of the Bishop VOR using a designated radial and the DME.

Require that all nighttime departures and arrivals at the Bishop Airport be conducted in accordance with the prescribed IFR procedures.