CURTISS WRIGHT C-46F near Fairbanks, AK — 2013-07-03

Probable cause

The failure of the right main landing gear side brace due to fatigue, which resulted in a collapse of the right main landing gear.

NTSB narrative

During the maintenance test flight, the flight crew moved the landing gear handle to the "down" position but did not observe the three green landing gear down-and-locked lights illuminate. After cycling the landing gear "several" times they observed a gear down-and-locked indication in the cockpit. After landing, while taxiing to parking, the right main landing gear collapsed, and the right wing and aileron struck the ground and sustained substantial damage. The right landing gear side brace fractured near the fuselage attach forging due to fatigue, which initiated near the weld between the large end fuselage attach forging and the outer tube. No obvious discontinuities such as porosity or undercutting were visually noted in the weld adjacent to the fracture.

Analysis

Primary failure mode

Mechanical failure

First missed decision gate

Inspect landing gear before taxiing after gear indication failure.

NTSB coding

• Comm system malf/failure · Taxi-from runway

Evidence available

• Photos
• 2 docket documents

Docket documents2

• Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1form
• Materials Laboratory 15 - Factual Report 13-099 (w 4 images)photos