What happened
On June 13, 2009, a Cessna 177RG, registration N52670, crashed while attempting a forced landing in a hotel parking lot in Gilford, New Hampshire. The flight had departed from Laconia Municipal Airport (LCI) with an intended destination of Portland International Jetport (PWM) in Maine.
Prior to departure, a fixed base operator lineman observed the pilot performing a preflight inspection. The lineman reported that during the engine start attempt, the engine "backfired or popped" twice before successfully starting. After takeoff, witnesses observed that the aircraft produced "no engine noise." The airplane' $\text{left wing and left horizontal stabilizer struck a 55-foot tree, after which the aircraft banked and rolled before impacting a second tree near ground level. Witnesses reported seeing smoke from the engine and large quantities of fuel exiting the wings. The pilot sustained 1 fatal injury.
The investigation
Investigators found that the engine was rotated approximately 80 degrees to the right of the longitudinal centerline. The investigation of the engine revealed that the oil cooler return line nipple fitting was fractured. Gouges were found on the surface of the hose end socket, consistent with contact from a wrench or tool.
Examination of the engine oil system showed that only approximately 2 ounces of oil remained in the entire system. While the oil pump was intact, all four engine connecting rod bearings showed signs of heat distress and had seized. Data from the aircraft's engine monitoring system indicated that approximately 45 seconds before the end of the flight, oil temperature and cylinder head temperatures (CHT) began to increase continuously. Approximately 30 seconds before the end of the recording, CHT began to decrease while the oil temperature continued to rise to about 195 degrees F.
Additionally, investigators found an oil trail on the taxiway starting near the engine run-up area and leading toward the runway. A review of maintenance records showed the aircraft had undergone an annual inspection on June 12, 2009, and this was its first flight since that inspection. The mechanic reported that the aircraft was signed off with the expectation that an engine run-up would be performed prior to flight, but the required run-up was not completed.
Findings
- The engine experienced a total loss of power due to oil exhaustion.
- The oil loss was caused by a fracture in the engine oil cooler return line nipple.
- The fracture was likely caused by a tool slipping and striking the socket.
- The aircraft was released for service following an annual inspection without the required engine run-up being performed.