N9084JPiper PA-32R-301 · 1985

On November 11, 2016, about 1650 Alaska standard time, a Piper Saratoga PA-32R-301, N9084J, sustained substantial damage during a forced landing following a total loss of engine power near Bethel Airport (BET), Bethel, Alaska. The commercial pilot sustained minor injuries. The airplane was registered to and being operated by the Alaska Department of Public Safety (DPS) as a visual flight rules (VFR) public-use flight under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and a VFR flight plan was filed. The flight originated from BET about 1635 destined for Nunapitchuk Airport (16A), Nunapitchuk, Alaska.

The pilot reported that after departing runway 1L at BET while climbing through 800 ft to the west, he felt a momentary vibration and noted the engine oil pressure at zero pounds per square inch (psi). He made an immediate left turn back to the airport and declared an emergency with BET air traffic control tower. While maneuvering for a landing at the airport, the engine began "popping loudly" and engine oil emanated from the oil access panel and splattered onto the wind screen. Shortly thereafter, the propeller stopped rotating and all engine power was lost. The pilot maneuvered to land in the tundra covered terrain southwest of the airport, away from residential areas. During the landing, the airplane encountered uneven terrain, which collapsed the left main and nose landing gears. The left wing impacted terrain and sustained substantial damage.

The pilot further reported that earlier that day he prepared for his flights by performing a preflight and checking the engine oil quantity, which was at 10 quarts. He did not remove the oil dipstick from the housing. He flew two passengers to 16A and returned to BET where he shut down the airplane, installed an engine cover and waited about three hours. When he returned to the airplane, the engine cowling was still warm and there were no fluid leaks evident. The airplane started normally and no ground run up was conducted for the second flight. The pilot stated that all the engine instruments were "in the green" before departing.

After the accident flight, Alaska DPS employees discovered a substantial amount of engine oil on the airport parking ramp where the airplane had been parked. The airplane's engine oil access panel was discovered open with no dipstick present during the airplane's recovery from the accident site. The oil dipstick was not recovered during airport ramp sweeps or other searches.

An external examination of the engine revealed that there was a hole in the crankcase above cylinder no. 4 with fractures emanating from the hole. There was a small amount of oil deposit around the oil dipstick neck, and none around the hole in the crankcase nor the top of the engine. All accessible fuel and oil lines were intact. No oil was present when the quick oil drain was opened. The oil access panel had impact marks on the underside of the panel that corresponded to the approximate size of the oil dipstick top.

The engine was disassembled and examined further. The no. 1 cylinder revealed no evidence of mechanical malfunction. The no. 2 and 6 connecting rods were in place; however, the no. 2 rod had dark discoloration and extrudence at the rod cap and the no. 6 piston skirt exhibited extensive scoring and carbon deposits in the direction of travel. The no. 3, 4 and 5 connecting rods were separated from the crankshaft by rod shank fractures with extensive thermal discoloration and deformation. Signatures were all indicative of engine operation without sufficient oil lubrication.

The oil sump pan was removed and large quantities of metal debris and fractured rods were observed. The oil suction screen was removed and indicated pieces of non-ferrous metal particles. The thermostatic oil cooler bypass valve was removed and examined. The crimp nut and valve seat remained intact and the spring was secure. The oil pump impeller was intact with no anomalies observed.

The oil coolers were each capped off at one end and 100 psi air pressure was applied. The left oil cooler exhibited no leaks. The right oil cooler (Aero-Classics, Inc. P/N 8000074, S/N 1041902) exhibited an air leak through a 2 inch separation at a mated brazed plate that was undetected during a visual exam. The right oil cooler was examined at the National Transportation Safety Board's materials laboratory. The fracture at the brazed seam exhibited signatures of over stress and no indications of fatigue, corrosion or material anomalies. A detailed factual report is available in the public docket.

The airplane was manufactured in 1985 and outfitted with a Lycoming IO-540-K1G5 engine. A review of maintenance records showed that the most recent annual inspection was completed on August 31, 2016. At the time of the accident, a total aircraft time of 6,989.1 hours and 213.4 hours since engine overhaul had accumulated. The maintenance records indicated that the engine was serviced with Phillips X/C SAE 20W50 oil and .5 bottle of CamGuard aviation additive during the annual inspection, which was 21.6 hours before the accident. According to the Piper Pilot Operating Handbook paragraph 8.19, this oil type was appropriate for the operating conditions of 0°F to 90°F.

Lycoming Service Instruction 1505 states that preheating of any Lycoming engine is required when the engine temperature has been allowed to drop below 10°F. According to the BET automated weather observations, the outside air temperatures were between 25°F and 21°F while the airplane was parked on the ramp prior to engine start.

The closest weather reporting facility was BET which was about 1 mile northeast of the accident site. At 1653 an automated special weather observation report indicated the following conditions: wind 030° at 10 knots, clouds and sky condition, scattered at 10,000 feet, broken at 25,000 feet; visibility 10 statute miles; temperature 21°F; dewpoint 19°F; and altimeter 29.98 inches of mercury.