Pilot Debrief

CESSNA 172N near Longmont, CO — 2025-05-04

Final reportCEN25LA168
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Date
2025-05-04
Location
Longmont, CO, USA
Airport
LMO
Aircraft
CESSNA 172N
Registration
N75775
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Approach

Probable cause

The disconnected throttle control that resulted in a loss of engine power due to improper maintenance.

NTSB narrative

The student pilot stated that he was on final approach when he noticed that the engine was not responding to his throttle control changes. The engine speed was about 2,000 rpm when he attempted a go-around; however, the engine power did not increase as he applied full throttle, and the airplane would not climb due to the low power setting. The student noted that the engine subsequently lost power completely and he executed a forced landing to a field. During the landing, the airplane struck a fence and nosed over. The airframe sustained substantial damage to the right wing, vertical stabilizer, and rudder. A post-accident examination determined that the throttle cable was disconnected from the carburetor. Both the throttle cable and the carburetor control arm moved freely and there was no evidence of damage to either component. The connecting hardware – bolt and nut – were not observed at the time of the examination. Airplane maintenance records revealed that a 100-hour inspection was completed three weeks before the accident, and the engine carburetor was replaced at that time. The airplane had accumulated about 9.9 hours flight time since that maintenance work. The mechanic stated that an apprentice had replaced the carburetor and the mechanic had gotten busy with other tasks and did not fully inspect the apprentice’s work.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted the approach earlier when engine power was insufficient.

NTSB coding

Evidence available

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

Docket documents5

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