Pilot Debrief

CESSNA 207 near Harlingen, TX — 2023-06-06

Final reportCEN23LA231
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Date
2023-06-06
Location
Harlingen, TX, USA
Airport
HRL
Aircraft
CESSNA 207
Registration
N91157
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

The improper installation of the throttle control arm to the throttle control cable attachment end, which resulted in a failure of the control arm and a loss of engine power in flight.

NTSB narrative

The pilot reported that shortly after takeoff on the fourth flight of the day, he leveled the airplane about 500 ft above ground level (agl), and set the engine controls for 2,500 rpm and 25 inHg manifold pressure. Immediately after adjusting the engine controls, the engine speed decreased to idle. The pilot made a forced landing to a field and the airplane sustained substantial damage to the left wing. A postaccident examination revealed that the throttle control lever had fractured, and the throttle control was no longer connected. The associated hardware remained attached to the throttle control cable attachment end. The engine and fuel control valve were recently overhauled, reinstalled in the airplane, and had accumulated 86.3 hours. A postaccident metallurgical examination revealed the throttle control lever attachment point exhibited wear and deformation on the surfaces of the areas that would have been in contact with the rod end attachment hardware. The throttle control lever attachment point also exhibited wear and a shallow impression of the splined collar on the inner surface of the attachment point bore, which was significantly worn. The splines on the collar were worn and uneven. The wear and deformation to the throttle control lever attachment point and the wear in the attachment point’s bore resulted in dimensions that no longer provided enough interference with the rod end attachment hardware to secure the connection. The throttle linkage hardware build-up on the accident airplane was different than specified by the airplane service manual and was missing a washer. The difference likely resulted in the hardware becoming loose over time and allowing excessive wear of the splined collar and lever arm, and ultimately the failure of the lever arm attachment point.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspection of throttle control lever as per service bulletin was not completed.

NTSB coding

Evidence available

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

Docket documents11

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