Right landing gear collapse during takeoff

Casualties unknown • Helena, MT, US

A pilot experienced a leftward veer and subsequent right landing gear collapse while applying power for takeoff.

What happened

Shortly after the pilot applied power for takeoff, the aircraft began to track to the left of the runway centerline. While attempting to correct the directional deviation, the right main wheel assembly and the right landing gear strut collapsed.

The investigation

Post-accident examination of the wheel assembly and the installed tire revealed that the outboard wheel subassembly had fractured in multiple locations along the bead seat ring. Additionally, investigators observed multiple fractures in the inboard wheel subassembly, noting that the brake disc had partially separated from the wheel.

Further review of the Type Certificate Data Sheet for the aircraft indicated that while multiple wheel-brake assemblies are approved for use, the specific assembly found on the aircraft was not listed as an approved installation. Furthermore, this particular wheel assembly was not approved for use with tires larger than size 7.00-6, whereas the aircraft was equipped with 8.00-6 size tires. The most recent annual inspection of the aircraft had been completed on March 7, 2002.

Probable cause

The use of an unapproved wheel assembly that was not rated for the larger tire size installed on the aircraft.

Frequently asked questions

What happened in the 2002-04-20 Stinson 108-2 accident near Helena, MT?

A pilot experienced a leftward veer and subsequent right landing gear collapse while applying power for takeoff.

What aircraft was involved and where did it happen?

The accident on 2002-04-20 involved a Stinson 108-2, registration N959D, at Helena, MT.

What was the probable cause of the accident?

The use of an unapproved wheel assembly that was not rated for the larger tire size installed on the aircraft.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20020426X00585. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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