Pilot Debrief

PALEN AVRO-504K near Rhinebeck, NY — 2009-10-17

Final reportERA10LA021
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Date
2009-10-17
Location
Rhinebeck, NY, USA
Airport
NY94
Aircraft
PALEN AVRO-504K
Registration
N4929
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Initial climb

Probable cause

A loss of engine power due to the in-flight separation of the number 3 cylinder valve rocker arm attachment hardware. Contributing to the accident was the improper maintenance inspection of the engine.

NTSB narrative

The pilot was performing an aerial demonstration for spectators. Shortly after takeoff, he heard a “thump,” the engine lost power, and he performed a forced landing in trees. Post-accident inspection of the wreckage revealed a keeper and cotter pin that connects the push rod to the number 3 cylinder valve rocker arm was missing. The high-tension spark plug lead to the number 5 cylinder was severed. The pilot, who also maintains the aircraft, believes the flailing spark plug lead flew into the commutator ring, shorting out other cylinders and leading to a total power loss. The missing hardware from the number 3 cylinder was never recovered. According to maintenance records, the airplane received a condition inspection on September 22, 2009. During that inspection, the number 5 cylinder was removed for repair and reinstalled, and the other rocker arms and valve springs were inspected.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have aborted takeoff after hearing the engine thump.

NTSB coding

Evidence available

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

Docket documents5

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