Pilot Debrief

CESSNA 172 near San Diego, CA — 2020-12-13

Final reportWPR21LA069
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Date
2020-12-13
Location
San Diego, CA, USA
Airport
MYF
Aircraft
CESSNA 172
Registration
N5098E
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Initial climb

Probable cause

A partial loss of engine power due to the fatigue fracture of the No. 3 exhaust valve rocker arm stud.

NTSB narrative

According to the flight instructor, the purpose of the flight was for the student pilot to practice touch-and-go landings. During the second takeoff, as the airplane was about 100-150 ft above ground level, he detected a loss of engine power and assumed control of the airplane. He landed the airplane on the remaining runway but overran the departure end of the runway and struck the airport perimeter fence. Both wings sustained substantial damage. Examination of the engine revealed that the No. 3 exhaust rocker arm stud was fractured. Metallurgical examination of the fracture surfaces on the rocker arm stud revealed that it had fractured due to fatigue. The fatigue fracture of the No. 3 exhaust valve rocker arm stud likely led to the partial loss of engine power.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspecting engine components during major overhaul could have prevented failure.

NTSB coding

Evidence available

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

Docket documents8

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