On May 24, 1991, an Aero Commander 690C (registration N81TR) operated by Casper Air Service was involved in an aviation accident near Denver, CO. Investigators recorded the probable cause as: The flap cable separated due to fatigue. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 6 related events involving the same aircraft type or operator are linked below.
While selecting full flaps during a VFR approach to Stapleton International Airport, the pilot of N81TR heard a dull thud. The aircraft rolled left, but control was maintained. The pilot raised the flaps, completed a normal no-flap landing, and inspection revealed a broken flap cable due to fatigue.
Incident Overview
During the mid-base leg of a visual flight rules (VFR) approach to Stapleton International Airport, the pilot of aircraft N81TR was selecting the full flap position. At that moment, a dull thud was heard. The aircraft subsequently began a roll to the left, but the pilot was able to maintain control until the flap handle could be raised. After selecting the flap-up position, the aircraft returned to normal flight characteristics. The pilot then accomplished a normal landing without flaps.
Post-Landing Inspection
Following the landing, the aircraft was parked and inspected. A broken flap cable was discovered. Subsequent laboratory tests determined that the cable had separated due to fatigue.
Probable cause
The flap cable separated due to fatigue.