Gulfstream Am Corp Comm Div 695A N79PH accident near Bishop, California

Probable cause

The failure of the left main landing gear upper arm forging due to fatigue cracking and subsequent overstress, which resulted in the collapse of the landing gear during the landing roll.

NTSB analysis

The pilot reported that before touching down on the runway with a 13-kt 50° right crosswind, the landing gear were down with the three green landing gear lights illuminated. After touching down and beginning the ground roll, the airplane pulled slightly to the left, the left wing dropped, and the airplane started to pull harder to the left. The pilot corrected with right rudder and brake, as well as reverse power on the right engine. The left wing dropped further, and the airplane pulled harder to the left before coming to rest about 10 ft from the left edge of the runway. The left main landing gear had collapsed, which resulted in substantial damage to the fuselage.

Postaccident examination revealed that the left main landing gear upper arm forging failed from fatigue cracking. The largest fatigue crack appeared to have initiated along multiple sites along scratch-like features on the outside surface of the arm. These cracks grew inward under spectrum loads until the loads from the accident landing could not be withstood by the remaining cross section, causing the part to fracture in overstress.

Text from the NTSB. Open the NTSB docket for WPR18LA129 for the full record.