Failure Of The Landing Gear Due To Material Deficiencies That Reduced The Strength Of The Landing Gear

Location: Glendale, Arizona Accident Number: WPR22LA357
Date & Time: September 27, 2022, 14:58 Local Registration: N151VR
Aircraft: Vashon Aircraft Ranger R7 Aircraft Damage: Substantial
Defining Event: Sys/Comp malf/fail (non-power) Injuries: 1 None
Flight Conducted Under: Part 91: General aviation - Personal

Analysis: According to the pilot, when the airplane reached 15-20 knots (kts) during the initial takeoff roll, the left main landing gear collapsed, and the airplane ground looped to the left. The airplane sustained substantial damage to the left elevator and left wing. 

Examination of the left main landing gear (MLG) leg determined it fractured due to preexisting cracks that initiated at the inboard side of the leg at the forward and aft sides of the forward hole for attaching the leg to the fuselage at the outboard attachment bracket. Examination of the crack revealed it existed before the accident flight; however, spacing between crack arrest features suggest the number of load cycles from initiation to failure was relatively low. 

A review of available flight data did not reveal a specific hard landing event that could have resulted in the initiation of the crack. The airplane’s main landing gear is made from a woven E-glass with epoxy resin and prepreg laminate that is pressed and then oven cured. The raw material is not aviation specific. Destructive testing of the failed landing gear and material samples from other gear manufactured from the same lot of material found the material did not meet minimum specified strength requirements. The material batch in question was traceable to 16 airplanes (30 gear legs), including 1 other airplane that had a similar failure following a hard landing. The owners of the affected airplanes were notified and the landing gear for some of the affected airplanes were replaced. Following this accident, the airplane manufacturer initiated a redesign of the landing gear and began performing destructive batch sample tests of the composite material used for every batch of gear legs to ensure each new gear leg meets minimum required strength requirements.

The accident is consistent with the landing gear being manufactured using material that did not meet the necessary strength requirements and subsequently failing after a crack developed in the landing gear. The event that initiated the crack was not identified based on available evidence.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- Failure of the landing gear due to material deficiencies that reduced the strength of the landing gear. 

FMI: www.ntsb.gov