NTSB Identification: CEN11LA669
14 CFR Part 91: General Aviation
Accident occurred Tuesday, September 27, 2011 in Marietta, OH
Probable Cause Approval Date: 06/11/2014
Aircraft: OWEN VANS RV-10, registration: N499RV
Injuries: 2 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

After completing basic flight maneuvers in the experimental amateur-built airplane, the pilot decided to return to the departure airport. During cruise descent, he heard a loud bang from the engine compartment, and oil began covering the windscreen. The pilot-rated passenger reported that there was a sudden “explosion” from the engine compartment that sounded similar to a “12 gauge double barrel shotgun.” The pilot relinquished control to the pilot-rated passenger, who had more experience in the accident airplane, and he subsequently made a forced landing to a nearby wooded area. A postaccident engine examination revealed significant heat and fire damage concentrated at the aft right side of the engine near the No. 5 engine cylinder. The fuel nozzle for the No. 5 engine cylinder was found disconnected from its corresponding cylinder head. The fuel injector line remained connected to the fuel nozzle, but the threaded portion of the fuel nozzle was not engaged to the cylinder head and could be lifted away from the cylinder head by hand. Further disassembly of the engine revealed that no internal component failures or mechanical anomalies occurred. The experimental engine, which had been modified from the original engine manufacturer’s design specifications, had been field-overhauled about 20 hours before the accident flight. It is likely that the disengaged fuel nozzle for the No. 5 engine cylinder allowed fuel to be introduced directly into the engine compartment and resulted in the in-flight engine fire/explosion when the fuel was ignited by hot engine exhaust and caused the heat and fire damage near the No. 5 engine cylinder. Additionally, the No. 5 engine cylinder would not have developed proper compression without the fuel injector nozzle engaged in the cylinder head. A postaccident review of the maintenance records found no history of unresolved airworthiness issues or any maintenance performed on the fuel injection system since the engine overhaul.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The in-flight engine fire and loss of engine power due to an improperly installed fuel injector nozzle during a recent engine overhaul.

Full narrative available

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