Pilot Debrief

PAZMANY PL 4 near Yates City, IL — 2014-05-10

Final reportCEN14LA235
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Date
2014-05-10
Location
Yates City, IL, USA
Airport
2C6
Aircraft
PAZMANY PL 4
Registration
N44PL
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Climb

Probable cause

A loss of propeller thrust due to a failure of the reduction drive unit resulting from the improper installation of the unit. Contributing to the accident was a lack of documentation for the reduction drive unit installation.

NTSB narrative

While in the airport traffic pattern, the airplane sustained a complete loss of thrust and an increase in engine speed, which the pilot interpreted as a loss of engine power to the propeller. He subsequently executed a forced landing to an open field. A postaccident examination revealed that the propeller reduction drive pulley had moved downward within the mounting bracket slot, creating slack in the cog belts that resulted in a loss of input drive power to the propeller. The reduction drive manufacturer did not provide any formal documentation for the installation. As a result, the pilot/builder was not aware that a secondary fitting to secure the pulley within the bracket needed to be installed with the drive unit components.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have checked the propeller reduction unit before flight.

NTSB coding

Evidence available

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

Docket documents7

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