Factual Report: Fatal on base to final

 - March 30, 2007, 1:18 PM

ROCKWELL AERO COMMANDER 690A, BISHOP, CALIF., AUG. 11, 2002–At about 1:23 a.m. Aero Commander N690TB crashed near Bishop Airport (BIH). The accident occurred during a descending turn between base and final approach. The twin turboprop was destroyed, and the pilot and three passengers were killed. The airplane was owned by the pilot, who was operating it under Part 91. VMC prevailed during the nighttime flight, and no flight plan had been filed. The aircraft departed from Oakland, Calif., at about 12:31 a.m. with three passengers and several hundred pounds of baggage.

At no time during the flight did the pilot report difficulty with the airplane. At 1:16 a.m. he told Oakland Center that he had Bishop in sight and was starting a VFR descent from 17,500 feet. As the aircraft descended through 16,000 feet, the controller terminated radar service, advised the pilot to change frequency and provided the Fresno altimeter setting, 29.81 inches.

Two witnesses on the ground saw the airplane enter the pattern, turn left onto base for Runway 30 and descend. During the turn, the airplane’s bank angle suddenly increased, reaching between 70 and 90 degrees. Then the airplane descended rapidly. It hit level desert terrain about 1.6 miles southeast of the threshold.

The owner-pilot held a commercial pilot certificate and a current medical. He had logged about 52 hours in the airplane in the previous 90 days–1.6 hours of which were at night, with three night landings. The aircraft did not have a current air-taxi operating certificate. On July 31, pressurization leaks were found on the airplane, most along fuselage seams, windows and the main entry door seal. The aircraft was serviced, but no log entry was made approving the airplane for return to service.

Later, another pilot reported the cabin pressure to be 3.2 psi, well below the normal 5.2 psi, and a passenger noticed an air leak in the floor air duct. The owner-pilot said a part had been ordered and repair was planned.

Bishop weather at 1:56 a.m. was wind from 300 degrees at five knots, clear skies, 10 miles of visibility, altimeter 30.04 and temperature 16 degrees C. There were no notams for nighttime operations on Runway 30. The lights and landing aids were reported as operational.

Both engines were operating at the time of initial impact, which was on level desert terrain at about 4,090 feet msl.