Casualties unknown

1990-09-11: Piper PA-601P (N321GB) — Monroe, MI

Monroe, MI, US

On September 11, 1990, a Piper PA-601P (registration N321GB) was involved in an aviation accident near Monroe, MI. Investigators recorded the probable cause as: A broken torque link on the right main landing gear scissors assembly. 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 broken torque link on the right main landing gear scissors assembly caused the aircraft to drift off the runway during landing. The pilot's use of controls, brake, and differential power could not prevent the excursion.

Incident Overview

During landing, the pilot felt the airplane pull right at touchdown. Despite combined use of flight controls, left brake, and differential power, the drift off the runway was reduced but not prevented. The aircraft ultimately departed the runway surface.

Mechanical Failure

A broken torque link on the right main landing gear scissors assembly allowed the lower strut to turn out of alignment. This caused the right main tire to scrub sideways throughout the landing roll, contributing to the loss of directional control.

History of Similar Failures

Since 1985, there have been 17 similar failures of the torque link. The manufacturer addressed this issue by incorporating a redesigned link in new production aircraft starting in 1982, with no failures reported on the redesigned part.

Service Bulletin

Service Bulletin 746A, issued in May 1986, offers a replacement link for the affected component.

Probable cause

A broken torque link on the right main landing gear scissors assembly.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X24224. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.