Pilot Debrief

CESSNA 172R near West Chicago, IL — 2009-07-19

Final reportCEN09IA456
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Date
2009-07-19
Location
West Chicago, IL, USA
Airport
DPA
Aircraft
CESSNA 172R
Registration
N77AF
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Approach

Probable cause

A partial loss of engine power due to the detachment of the throttle control cable from the throttle assembly during a landing approach. Contributing to the accident was the lack of a redundant means to preclude the detachment of the cable from the throttle assembly.

NTSB narrative

A previous maintenance entry in the airplane logbook indicated that the firewall was replaced and the airplane returned to service. The airplane had been operated for about 63 hours when the throttle control cable became unscrewed from the rod end of the throttle assembly during an instructional flight. The flight instructor and student pilot lost throttle control during an approach to a destination airport when engine speed increased to about 2,200-2,300 rpm. The flight instructor landed the airplane without further incident. The throttle control assemblies for the airplane do not have a key way at the throttle control knob to prevent rotation of the cable and unscrewing of the cable from the rod end should the jamnut become loose. The operator recommended that a safety device and not just a jamnut be installed to prevent the throttle control from disconnecting from the rod end.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Throttle control failure during approach could have been addressed earlier.

NTSB coding

  • Powerplant sys/comp malf/fail · Approach

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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