Casualties unknown

1991-03-12: Cessna 421B (N924MD) — Deer Valley Aviation, Inc — Tucson, AZ

Tucson, AZ, US

On March 12, 1991, a Cessna 421B (registration N924MD) operated by Deer Valley Aviation, Inc was involved in an aviation accident near Tucson, AZ. Investigators recorded the probable cause as: Fatigue failure of the right engine turbocharger exhaust clamp. 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 1781061362Data APIEditorial standards

A Cessna 421 experienced a right engine power loss shortly after takeoff. The aircraft subsequently struck power lines and impacted a field. Investigation revealed a fatigue failure in the turbocharger exhaust clamp.

Incident Overview

A Cessna 421, operated under Part 135, experienced a loss of power in the right engine 10 to 15 seconds into the initial climb following takeoff. The pilot flying was a company pilot occupying the left seat, while a check airman (the pilot in command) was in the right seat. A third company pilot was seated in the back.

Emergency Sequence

Upon detection of the power loss, the third pilot reported seeing fire emanating from the right engine nacelle. According to the pilot in command, the second pilot "apprehensively attempted the emergency procedures and gave the airplane to me as the airspeed rapidly declined." The pilot in command observed power lines directly ahead and chose to fly under the wires toward a vacant field. The aircraft collided with the power lines and subsequently impacted the ground in the field.

Post-Accident Examination

An on-site examination of the aircraft revealed that the right engine turbocharger exhaust clamp had failed, allowing exhaust gases to flow through louvers in the right nacelle. No evidence of an actual fire was found. A metallurgical examination of the failed clamp determined that the failure resulted from fatigue.

Probable cause

Fatigue failure of the right engine turbocharger exhaust clamp.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X16630. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.