Pilot Debrief

CESSNA 210 near Tacoma, WA — 2023-05-30

Final reportWPR23LA213
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Date
2023-05-30
Location
Tacoma, WA, USA
Airport
TIW
Aircraft
CESSNA 210
Registration
N9574X
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Approach

Probable cause

A fatigue failure of the left main landing gear hydraulic actuator, which resulted in a loss of hydraulic fluid that prevented the pilot from lowering the landing gear to the fully extended position and maintaining directional control after landing.

NTSB narrative

While on the downwind leg of the traffic pattern, the flight instructor was unable to fully extend the landing gear. The landing gear appeared to be stuck in a transitional position, which the flight instructor attempted to resolve by moving the gear selector back to the gear-up position; however, she observed no movement. After about 1.5 hours of troubleshooting the landing gear, the flight instructor decided to land with the gear partially extended. The airplane touched down with the nose gear locked and the pilot was unable to attain directional control. The airplane veered off the runway, coming to rest in the grass. Examination of the hydraulic system revealed that the left main landing gear hydraulic actuator barrel was fractured adjacent to the end cap. A fracture at the retainer clip groove exhibited striations consistent with fatigue crack propagation, and other fractures through the barrel exhibited signatures of overstress failure. It is likely that, once the fatigue crack grew to a significant depth, the housing cracked further from overstress and hydraulic fluid leaked out of the system, preventing the landing gear from extending properly. The airplane manufacturer had previously issued instructions for modification of some landing gear hydraulic actuators installed on the accident airplane make and model, and an FAA airworthiness directive (AD) was subsequently issued to mandate the modifications. The maintenance records showed that the AD was performed on the accident airplane. This is at least the fourth known failure of this model of actuator that resulted in an accident. The location, size, and physical features of the cracks were consistent among the accidents.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Flight instructor could have opted for an immediate landing instead of troubleshooting.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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