Casualties unknown

Runway Excursion During Taxi Due to Brake Failure (N600A)

Butler, PA, US

On August 21, 1983, a Piper PA-22 TRIPACER (registration N600A) was involved in an aviation accident near Butler, PA. Investigators recorded the probable cause as: The split diaphragm in the master cylinder resulted in loss of hydraulic fluid and subsequent braking action. 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

An aircraft ran off the runway and nosed over after landing when the brakes failed due to a split diaphragm in the master cylinder, causing loss of hydraulic fluid and braking action.

Event Description

After landing, while taxiing down runway 17, the pilot reported that the brakes gave way. Realizing the brakes were not holding, the pilot shut off the engine using the mixture control. To avoid entering a highway, the pilot turned left off the side of the runway. The nose gear then struck a 4-foot ditch, causing the aircraft to nose over.

Investigation Findings

Post-accident examination of the braking system revealed that the brakes were soft and spongy when applied. Hydraulic fluid was observed leaking from the vent hole in the master cylinder. Further inspection identified that the diaphragm within the master cylinder had split, leading to a loss of hydraulic fluid and subsequent loss of braking action.

Probable cause

The split diaphragm in the master cylinder resulted in loss of hydraulic fluid and subsequent braking action.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X44335. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.