Pilot Debrief

DIAMOND AIRCRAFT IND INC DA 20-C1 near Englewood, CO — 2013-05-22

Final reportCEN13LA291
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Date
2013-05-22
Location
Englewood, CO, USA
Airport
KAPA
Aircraft
DIAMOND AIRCRAFT IND INC DA 20-C1
Registration
N571MA
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Approach

Probable cause

The in-flight separation of the engine throttle lever and throttle cable due to maintenance personnel not applying sufficient torque to the self-locking nut or improperly reusing a degraded self-locking nut.

NTSB narrative

While on final approach during an instructional flight, the engine became unresponsive to throttle movements. The flight instructor took control of the airplane from the student pilot and made a forced landing, during which the airplane rolled onto soft ground and nosed over to an inverted position. Engine examination revealed that the engine throttle lever and throttle cable had become disconnected and that the bolt connecting these two components was located at the bottom of the engine cowling. A self-locking nut, which normally secures this bolt, was missing and not located. Therefore, it is likely that maintenance personnel did not apply sufficient torque to the nut or improperly reused a degraded self-locking nut, which resulted in the eventual loosening of the nut and the in-flight separation of the engine throttle lever and throttle cable.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Reassessing engine condition before final approach could have prevented the forced landing.

NTSB coding

Evidence available

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

Docket documents4

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