Pilot Debrief

CESSNA 120 near Lone Pine, CA — 2015-10-24

Final reportWPR16LA018
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Date
2015-10-24
Location
Lone Pine, CA, USA
Airport
O26
Aircraft
CESSNA 120
Registration
N3124N
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

The fracture of the left main landing gear (MLG) wheel axle due to fatigue, which resulted in the separation of the left MLG wheel during takeoff from a dirt airstrip.

NTSB narrative

The private pilot was taking off from a dirt airstrip for a personal cross-country flight. He reported that, during the takeoff roll, it felt like the left main landing gear had hit soft soil and that the drag had increased. He attempted to correct for the condition, but the left MLG wheel continued to drag. The airplane then suddenly nosed over, which resulted in substantial damage to the wings and empennage. Postaccident examination of the airplane revealed that the left MLG wheel axle was fractured, which resulted in the separation of the left MLG wheel. A detailed examination of the fracture surface identified a fatigue fracture that emanated from the outer surface of a circumferential weld between the lateral tube portion and the vertical plate portion of the axle. The investigation could not determine what event initiated the fatigue cracking; however, the origin areas were covered in zinc-chromate primer, which indicates that the axle was painted when the circumferential weld contained a preexisting crack.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted takeoff upon feeling the drag from the left main landing gear.

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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