Casualties unknown

Engine Power Loss During Descent; Plugged Fuel Vent Lines Found (N961T)

Apple Valley, CA, US

On November 15, 1996, a Beech 35-33 (registration N961T) operated by Norman E. Nissen was involved in an aviation accident near Apple Valley, CA. Investigators recorded the probable cause as: The left auxiliary fuel cell vent lines were plugged by insects and mud at two different internal locations. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

While descending to Apple Valley Airport, the engine lost power. The pilot switched tanks but could not restart and landed in rough terrain, colliding with a berm. Postcrash inspection found left auxiliary fuel vent lines plugged by insects and mud.

Accident Sequence

According to the pilot's report, while descending toward Apple Valley Airport, the engine began to run rough and then lost power. At the time, the pilot was using the left auxiliary fuel cell. He immediately switched to the right main tank, which was the fullest, but was unable to restart the engine even after positioning the fuel selector to other tanks. As the aircraft neared the ground, the pilot attempted to land on a dirt road but lacked sufficient altitude and landed in rough terrain. The aircraft collided with a berm during the landing sequence.

Fuel System Examination

After the accident, recovery personnel found approximately 23 gallons of fuel in the right main tank and 10 gallons in the left auxiliary. Both tanks were leaking fuel at the time. The fuel selector was found positioned to the right main tank. Inspection of the fuel system revealed that the left auxiliary fuel cell vent lines were plugged by insects and mud at two different internal locations.

Engine Inspection

Postcrash inspection of the engine showed no discrepancies.

Probable cause

The left auxiliary fuel cell vent lines were plugged by insects and mud at two different internal locations.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001208X07072. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.