Overview
On August 14, 2012, at about 0620 Pacific daylight time, a Rockwell International S-2R, registration N8468V, was substantially damaged during a forced landing following a loss of engine power after takeoff. The accident occurred near Royal City, Washington. The certified commercial pilot sustained minor injuries. The aircraft was registered to Royal Flying Service, Inc. and operated under 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight originated from a private airstrip approximately one minute prior to the accident.
Pilot Account
The pilot reported that shortly after takeoff, while carrying 325 gallons of liquid fungicide, the engine began running rough. Unable to maintain altitude and needing to clear a set of wires ahead, the pilot partially dumped the load. After clearing the wires, the pilot attempted to land on a paved road. Upon touchdown, the airplane veered off the road and entered a ditch, where it caught fire and was consumed.
Inspection Findings
A Federal Aviation Administration (FAA) airworthiness aviation safety inspector conducted an onsite inspection of the wreckage. The inspection revealed that the number 2 cylinder exhaust rocker boss housing had separated from the cylinder. This separation prevented the exhaust valve on that cylinder from opening, which resulted in the loss of engine power. No other evidence of engine damage or malfunction was noted.
Maintenance Records
A review of the company maintenance records by the FAA inspector showed that all required inspections had been completed. This included compliance with FAA Airworthiness Directive (AD) 99-11-02, which specifies inspection requirements for the accident aircraft's cylinder type. The AD mandates a recurring inspection every 100 hours; at the time of the accident, the engine had accumulated 91 hours since its last inspection.