Pilot Debrief

CESSNA 175 near Hot Springs, SD — 2021-09-10

Final reportCEN21LA416
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Date
2021-09-10
Location
Hot Springs, SD, USA
Airport
HSR
Aircraft
CESSNA 175
Registration
N9343B
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Landing

Probable cause

The tensile overload failure of the main landing gear attachment bolt, which resulted in separation of the left main landing gear and a loss of control during landing.

NTSB narrative

The pilot reported the airplane touched down “with a gentle skip then easing forward on the yoke pinned my main gear firmly on the turf.” During the landing roll, the airplane began to veer to the right, and the pilot applied rudder inputs to correct. The airplane subsequently spun around and came to rest upright with the left main landing gear leg separated. The airplane sustained substantial damage to the left wing and main landing gear box structure. An attachment bolt for the left main landing gear strut was found fractured and separated from the strut. Metallurgical examination of the fractured bolt and the landing gear strut plate revealed the bolt fractured due to tensile overload that led to shearing of the bolt threads. The bolt was fully threaded into the self-locking nut plate and there was no evidence of looseness before the failure. The damage pattern of the fractured bolt and bent strut plate were consistent with an overload failure of the inboard attachment with no evidence of any preexisting damage or weakness in the attachment. It is likely the main landing gear failure was the result of excessive loading on the attachment during the landing.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspection of landing gear components prior to flight could have identified issues.

NTSB coding

Evidence available

  • Photos
  • 4 docket documents
View NTSB final reportView NTSB docket

Docket documents4

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