LAX02FA251

The pilot entered the left-hand traffic pattern at an uncontrolled airport on a dark moonless night. Witnesses reported observing the airplane in a left descending turn. As the airplane turned onto the base leg, its left bank angle suddenly became steep. The airplane rapidly descended until colliding with level desert terrain 1.63 nm from runway 30's threshold. There were no ground reference lights in the accident site area. An examination of the airplane structure, control systems, engines, and propellers did not reveal any evidence of preimpact malfunctions or failures. Signatures consistent with engine power were found in both the engines and the propellers. The wreckage examination revealed that the airplane descended into the terrain in a left wing and nose low attitude. Fragmentation evidence, consisting of the left navigation light lens and left propeller spinner, was found near the initial point of impact. The wreckage was found principally distributed along a 307- to 310-degree bearing, over a 617-foot-long path. The bearing between the initial point of impact and the runway threshold was 319 degrees. The pilot's total logged experience in the accident airplane was 52 hours, of which only 1.6 hours were at night. The pilot was familiar with the area, but he had made only two nighttime landings within the preceding 90 days. Review of the recorded ATC communications tapes did not reveal any evidence of pilot impairment during voice communications with the pilot.

History of flight

On August 11, 2002, about 0123 Pacific daylight time, an Aero Commander 690A, N690TB, descended into terrain near the Bishop Airport, Bishop, California. The accident occurred during a descending turn between the base and the final approach legs in the airport's traffic pattern. The airplane was destroyed. The commercial certificated pilot and three passengers were fatally injured. The airplane was owned by the pilot who was operating it under 14 CFR Part 91. Visual meteorological conditions prevailed during the dark, nighttime flight, and no flight plan had been filed. The accident flight departed from Oakland, California, on August 11, about 0031.

About 4.5 hours earlier (a few minutes after 2007), the pilot had completed a flight from Bishop to the Metropolitan Oakland International Airport. Oakland. During this flight the pilot was accompanied by a friend. After arrival at Oakland, about 2025, the pilot purchased fuel for the return nighttime flight to Bishop. By prior arrangement, the pilot had agreed to transport two additional passengers from Oakland to Bishop. The passengers arrived in Oakland via a scheduled airline flight. The passengers, along with several hundred pounds of their luggage, boarded the pilot's airplane, and the accident flight commenced.

According to the Federal Aviation Administration (FAA), at no time during the pilot's flight between Oakland and Bishop did he communicate that he was experiencing any difficulty with the airplane. By 0102:14, the pilot had climbed to 17,500 feet mean sea level (msl) and was over the Sierra Nevada Mountains.

At 0116:31, the pilot informed an Oakland Air Route Traffic Center controller that he had "Bishop in sight" and was starting a descent under visual flight rules. The controller acknowledged the pilot's transmission, terminated radar service, advised the pilot to change to the advisory frequency, and said "good night." About this time, at 0116:34, the last radar return shows the airplane descending through 16,600 feet.

The pilot replied to the controller at 0116:47, and stated "local control good night sir thanks." There were no further recorded transmissions from the pilot.

As the airplane approached the Bishop airport, two ground-based witnesses observed the airplane's lights. The witnesses described their observations to the National Transportation Safety Board investigator. Based upon the witnesses' statements, the airplane entered the Bishop airport's left traffic pattern, turned left onto the base leg for runway 30 and descended. During the subsequent left turn onto the final approach leg to runway 30, the airplane's bank angle suddenly increased until reaching between 70 and 90 degrees. Then the airplane descended rapidly. The airplane impacted level desert terrain about 1.6 nautical miles southeast (142 degrees, magnetic) from runway 30's landing threshold.

Personnel information

The pilot held a commercial pilot certificate with airplane multiengine land and instrument airplane ratings. He was also rated to fly a CE-500.

The pilot's personal flight time logbook was provided to the Safety Board investigator for review. The logbook covered the period from January 29, 1990, when the pilot's total flight time was listed as being 829.3 hours, to August 9, 2002, when the pilot's total flight time was 3,799.6 hours. A review of the logbook shows that the pilot first flew N690TB on May 8, 2002.

By the time of the accident, the pilot's total logged flight experience in the Aero Commander 690A was about 52 hours. During the 90 days preceding the accident, the pilot had flown for about 52 hours, all in the accident airplane. Prior to the accident flight, 1.6 hours of this time were at night.

The pilot's logbook further indicates that during this 90-day period preceding the accident, he had made two landings at night. This does not include the landing at Oakland, which occurred about sunset.

Aircraft information

The Aero Commander 690A was manufactured in 1973. It had a standard, normal, airworthiness certificate. The airplane was not equipped with cockpit voice or flight data recorders, nor were they required under FAA regulations.

The airplane's maintenance records indicated that on May 8, 2002, at a Hobb's hour meter time of 1,678.6 hours and a listed total airplane time of 3,726.8 hours, the airplane received an annual inspection.

According to information in the airplane's logbook number 3, the last maintenance that was performed was dated July 10, 2002. This maintenance involved removal and replacement of the left and right propeller governors and other items. The repair station that performed the work indicated that the airplane was approved for return to service at an indicated meter time of 1,712.8 hours. The Safety Board investigator calculated that the airplane's total time on this date was about 3,761 hours. At the time of the accident, the airplane's total time was estimated at 3,782 hours.

The Airesearch Manufacturing Company of Arizona (subsequently called Garrett, Allied-Signal and Honeywell) manufactured the two model TPE331-5-251K turboshaft engines that were installed in the airplane. The maintenance records indicate that the engines' and airframe's total time were the same.

Regarding the pressurization system, according to the airplane's flight manual, the system can be set to maintain a normal cabin differential pressure of 5.2 pounds per square inch (psi). The maximum (red line) differential pressure is 5.4 psi.

On July 31, 2002, the accident airplane was examined by a Reno, Nevada, repair station for a discrepancy. The repair station's documentation indicates that it found a pressurization leak in the airplane. In summary, the repair station found many leaks on the left and right-hand side of the airplane between fuselage stations 5.54 and 144.0. Most of the leaks were located along fuselage seams. Minor leaks were located around the windows and the main entry door seal. The owner was advised of the leaks. It was the owner's decision to take the airplane "as is" and have the leaks corrected in Chico, California. The repair station's director of maintenance reported that no log entry was made approving the airplane for return to service. The airplane was put back together, whereupon the owner reportedly flew it back to Bishop.

A pilot who flew the airplane on August 8, 2002, reported that the cabin pressure was 3.2 psi and commented that the system was in need of repair. He stated that at 21,000 feet msl, the cabin pressure was at 10,000 feet. Reportedly, a passenger on the flight noticed an air leak in the floor air duct. The pilot reported advising the owner that the airplane was not maintaining adequate pressure during his flight. The owner reportedly told him that a part had been ordered at a repair facility in Chico, California, to resolve the problem. The owner told him he planned to take the airplane to Chico for repair the following week.

Meteorological information

Sunset and the end of civil twilight occurred at Oakland on August 10 at 2008 and 2036, respectively.

At 0123 on August 11, the moon was not visible at Bishop. It had set the previous day at 2136, and was to rise at 0922 on August 11.

At 0056 and 0156 on August 11, the Bishop airport reported its weather conditions, in part, as follows: wind from 300 degrees at 3 and 5 knots, respectively. The visibility was 10 statute miles, and the sky was clear. The altimeter was 30.04 inches of mercury, and the temperature was 18 and 16 degrees Celsius, respectively.

The Bishop airport is equipped with an automatic surface observing system (ASOS), which continuously transmits the local weather conditions.

Aids to navigation

According to the FAA, all electronic aids to navigation pertinent to the airplane's route of flight were functional