Casualties unknown

Airline Transport Pilot Defers Brake Repair, Resulting in Runway Overrun (N9736M)

Mountain Villag, AK, US

On September 17, 1986, a Cessna 207A (registration N9736M) was involved in an aviation accident near Mountain Villag, AK. Investigators recorded the probable cause as: The pilot's decision to defer brake repairs, which led to the fatigue failure of the right brake line and subsequent loss of braking capability during landing. 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 ATP and A&P mechanic deferred brake repairs until the end of the day. The right brake line failed during landing, causing a runway overrun and substantial aircraft damage.

What happened

The pilot, who held both an airline transport pilot certificate and a certified airframe and powerplant mechanic rating, made the decision to defer necessary brake repairs until the conclusion of the day's flying operations. Despite this deferral, the fatigue on the right brake line caused it to fail before the end of the day's activities.

During the landing phase, the failure of the braking system became apparent. Without functional brakes, the aircraft was unable to stop within the available runway distance. The acft overran the end of the runway, resulting in substantial damage to the airframe.

The investigation

The investigation focused on the mechanical state of the braking system and the pilot's maintenance decisions. It was determined that the right brake line had suffered from fatigue failure. The timing of this failure coincided with the landing phase, directly leading to the loss of braking capability.

Findings

  • Substantial damage to the aircraft resulting from the runway overrun.
  • The pilot's decision to defer critical brake repairs contributed to the incident.
  • Fatigue failure of the right brake line was the mechanical cause of the brake system failure.
  • The aircraft overran the end of the runway due to the lack of braking effectiveness during landing.

Probable cause

The pilot's decision to defer brake repairs, which led to the fatigue failure of the right brake line and subsequent loss of braking capability during landing.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X34680. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.