Pilot Debrief

Beech E90 near Greenville, TX — 2019-06-12

Final reportCEN19LA166
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Date
2019-06-12
Location
Greenville, TX, USA
Airport
AFW
Aircraft
Beech E90
Registration
N176TW
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

The fatigue failure of the right main landing gear upper torque knee.

NTSB narrative

The pilots were performing an instructional flight with multiple takeoffs and landings when, during one takeoff, the pilots heard a loud noise, and the right main landing gear (MLG) wheel assembly departed the airplane. The pilots elected to perform an emergency landing at another airport due to its larger runways and emergency personnel and equipment. The airplane landed and came to rest upright on the runway surface. Examination of the airplane after landing revealed that the right main wheel/tire and lower shock absorber assembly departed the upper shock absorber assembly. The separated assembly, which was located near the departure airport, impacted the right horizontal stabilizer after separation, which sustained substantial damage. Metallurgical examination of the assembly revealed that the MLG fractured at the connection between the upper and lower torque knees. Fatigue was identified on a fractured piece of the upper torque knee, and other fractures on the torque knee were consistent with overload. Corrosion assisted in crack initiation, and the crack propagated through fatigue until a critical crack length was reached. It is likely that the fatigue area fractured first and the other connections experienced an increase in loading, which caused them to separate from the MLG assembly.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Performing required inspections on the MLG torque knees as per service bulletins.

NTSB coding

Evidence available

  • 10 docket documents
View NTSB final reportView NTSB docket

Docket documents10

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