Casualties unknown

1991-07-20: Cessna C-172P (N54694) — South Bay Aviation — Hesperia, CA

Hesperia, CA, US

On July 20, 1991, a Cessna C-172P (registration N54694) operated by South Bay Aviation was involved in an aviation accident near Hesperia, CA. Investigators recorded the probable cause as: A STUCK ENGINE THROTTLE DUE TO IMPROPER MAINTENANCE PROCEDURES. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 4 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A pilot diverting to Hesperia due to weather found the throttle frozen at an intermediate setting, unable to add power. The aircraft collided with power lines while maneuvering to the runway. Investigators confirmed the throttle was frozen, and maintenance records showed six prior complaints of intermittent sticking.

Incident Overview

During a flight, the pilot decided to divert to Hesperia due to adverse weather conditions. While executing the en route letdown, the pilot attempted to add power but discovered the throttle control was frozen and could not be moved. The throttle remained at a power setting insufficient to maintain level flight. As the aircraft maneuvered toward the runway, it collided with high-tension power lines.

Post-Accident Examination

Following the accident, Federal Aviation Administration (FAA) airworthiness inspectors examined the aircraft. They confirmed that the throttle was frozen in an intermediate setting, preventing any adjustment of engine power.

Maintenance History

The aircraft's engine had been overhauled on June 18, 1991. As part of this overhaul, the carburetor was also overhauled, which included the installation of new throttle bushings and a shaft. However, records from Southbay Aviation documented six prior complaints by renter pilots that the throttle was sticking intermittently. The corrective action recorded on the discrepancy sheets for these complaints consisted of replacing the throttle cable.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X17612. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.