Pilot Debrief

ROCKWELL S2R near Royal City, WA — 2012-08-14

Final reportWPR12LA356
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Date
2012-08-14
Location
Royal City, WA, USA
Airport
8WA
Aircraft
ROCKWELL S2R
Registration
N8468V
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

The loss of engine power due to the separation of the No. 2 cylinder exhaust rocker boss housing, which prevented the exhaust valve from opening.

NTSB narrative

The pilot stated that shortly after taking off for the aerial application flight the engine began to run rough. Because he could not maintain altitude and was concerned about clearing a set of power lines in front of him, the pilot partially dumped the airplane’s aerial application load. After the airplane cleared the power lines, the pilot attempted to land on a road; however, during the touchdown the airplane veered off of the road and into a ditch. A postaccident fire consumed the airplane. A postaccident examination of the engine revealed that the No. 2 cylinder exhaust rocker boss housing had separated from the cylinder, which prevented the cylinder's exhaust valve from opening and resulted in the loss of engine power. Maintenance records revealed that the cylinder had been inspected in accordance with the time interval specified by the applicable Federal Aviation Administration airworthiness directive (AD). The AD specifies a 100-hour recurring inspection requirement; the engine had accumulated 91 hours since its last inspection.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have aborted takeoff upon detecting engine roughness.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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