Casualties unknown

2000-09-22: Beech B99 (N99TH) — Alpine Air — Missoula, MT

Missoula, MT, US

On September 22, 2000, a Beech B99 (registration N99TH) operated by Alpine Air was involved in an aviation accident near Missoula, MT. Investigators recorded the probable cause as: A loss of directional control due to a brake locked as a result of snow and ice contamination. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

An airplane experienced a right brake lock-up upon landing, veered off the runway, and struck a taxiway light and runway marker. Post-accident inspection revealed ice and snow deposits on several components but no mechanical malfunction.

Accident Sequence

The airplane touched down on the centerline of runway 29. When the pilot applied the brakes, the right brake locked up, causing the airplane to veer sharply to the right. The pilot attempted to correct by applying left brake, left rudder, and reversing the left propeller, but the airplane continued to the right. It subsequently collided with a taxiway light and a runway marker before departing the right side of the runway. The fuselage sustained substantial damage.

Post-Accident Findings

Photographs taken after the accident revealed ice and snow deposits on the cargo pod, right lower engine nacelle, main landing gear strut, and the right dual brake assembly. The landing runway in Missoula was dry, but the departure runway at Billings had been contaminated with snow and slush.

Inspection Results

An inspection conducted by inspectors from the FAA Helena, Montana, Flight Standards District Office found no evidence of any system mechanical malfunction that would have resulted in a brake failure.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X22076. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.