NTSB Factual Report

On April 15, 2009, about 1945 Pacific daylight time, a Raytheon Aircraft Company A36 single-engine airplane, N464TJ, was substantially damaged during a forced landing following a loss of engine power near Lopez Island, Washington. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot and his three passengers were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. The cross-country flight originated from the Snohomish County Airport (PAE), Everett, Washington about 30 minutes prior to the accident with an intended destination of Friday Harbor, Washington.

In a written statement, the pilot reported that prior to the flight; he conducted a pre-flight inspection of the airplane. During the inspection, he verified the fuel level and "twisted off the yellow oil filler cap and noted the very different color and viscosity of the mineral oil in the engine compared to normal." The pilot noted the oil level was "one quart below the completely full mark." The pilot completed his inspection and proceeded to start the engine and taxi for takeoff.

Following an uneventful takeoff, the pilot remained within the airport traffic pattern briefly before continuing on to his intended destination. During cruise flight at an altitude of 6,500 feet mean sea level (msl), the pilot set the propeller rpm to 2,300 rpm. After adjusting the radio frequency, he noticed that the propeller rpm had increased to 2,500 rpm and was slowly rising to 2,600 rpm. The pilot adjusted the propeller rpm to 2,300 rpm. While monitoring the propeller rpm, he observed the propeller rpm steadily rising from 2,300 rpm to 2,600 rpm. The pilot readjusted the propeller rpm to 2,300 rpm and continued to monitor the propeller rpm. He noted that the propeller rpm began to quickly rise past 2,500 rpm. The pilot stated he "pulled the rpm lever all the way back, but the rpm's continued to climb again." The pilot further stated that he "couldn't control the rpm any longer with that lever as it was all the way back, so I immediately pulled the throttle back and both the rpm's [and] manifold pressure dropped."

The pilot initiated a turn towards Lopez Island and looked to check the engine's oil pressure and temperature. Subsequently, the pilot heard a "loud bang" immediately followed by a "significant trail of white smoke pouring over the wind screen" and a loss of engine power. The pilot initiated a forced landing to a nearby road with no traffic observed. As the airplane descended through about 50 feet above ground level (agl), the pilot observed a vehicle turn onto the road, traveling in the opposite direction of his flight path. The pilot extended his approach to landing, clearing the vehicle and landed on the road. The pilot stated that due to telephone poles on the right side of the road, he aligned the airplane slightly left of the center of the road. During the landing roll, the left wing struck a street sign and subsequently struck "two or three large wooden fence posts that were hidden in the bramble of blackberry bushes which spun the airplane around 270-degrees." The airplane came to rest upright in the middle of the road.

Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the left and right wings were structurally damaged. The empennage of the airplane was twisted and displaced to the right. Examination of the engine revealed that the oil filler cap was unsecured from the oil filler neck. About one quart of oil remained within the oil sump. A hole was observed above the number four cylinder. The wreckage was recovered to a secure location for further examination.

On May 27, 2009, the engine and airframe were examined under the supervision of the NTSB investigator-in-charge.

Examination of the engine revealed that three of the four engine mounts were separated. Two holes were observed in the crankcase above the number two and four cylinders. The left and right magnetos, vacuum pump, fuel pump, throttle body fuel control unit, and fuel manifold valve remained attached to the engine. The propeller governor remained attached to its mount pad, however the two aft nuts were found loose. Multiple threads of the propeller governor mount studs were observed between the top and bottom aft nuts, washers, and propeller governor. The propeller governor was removed from the engine and the seal was found intact. Oil residue was observed on the aft side of the propeller governor mount pad and propeller governor seal. Oil residue was also noted around the surrounding area of the number six intake and exhaust push rod housings, just aft of the propeller governor mount pad.

The oil filler neck was found intact and undamaged. The oil filler neck cap was also intact and undamaged. The oil pump was intact and undamaged. Metallic debris was noted within the oil pump cavity area along with scratches on the cavity walls. The oil filter remained attached to the engine and was undamaged. The oil filter was removed and cut open using an oil filter cutter. The internal oil filter element exhibited metallic debris.

The number five and six cylinders were removed from the engine. Extensive mechanical damage was observed within the internal areas of the crankcase and on the number one, two, three, four, and five cylinder skirts.

Disassembly of the engine crankcase revealed that the number one and six connecting rods were intact and remained attached to their respective pistons and the crankshaft. The number five connecting rod remained attached to the piston and crankshaft and exhibited thermal discoloration and mechanical damage. The number two, three, and four connecting rods were observed separated from the crankshaft.

Examination of the airframe revealed that oil residue was located on the left engine cowling door, about mid span, lower left side of the engine cowling, left fuselage, and engine compartment.

Review of the engine maintenance logbook revealed that the engine was disassembled and inspected due to a propeller strike on March 25, 2009 at an engine total time of 1,237.1 hours. Review of the airframe maintenance logbook revealed that an annual inspection was completed on April 7, 2009, at an airframe total time of 1,237.1 hours. Review of a company maintenance work order dated April 7, 2009, stated in part "Remove propeller and engine following prop strike on tow bar...reinstall engine, propeller, and governor following service..." at an airframe total time of 1,237.1 hours.

Using the observed HOBBS meter hour reading of 1,237.6 hours, the airplane had accumulated 0.5 hours total flight time since the time of the engine installation and annual inspection. The pilot reported that the accident flight was the first flight following the annual inspection and engine propeller strike inspection.

NTSB Probable Cause

A loss of engine power during cruise flight due to oil starvation. The oil starvation event was due to the failure of maintenance personnel to tighten the aft mounting nuts for the newly installed propeller governor and the pilot’s failure to secure the oil filler cap during the preflight inspection.