PARKER, AZ, USA
N41981
PIPER PA-28-151
THE PILOT REPORTED THAT WHILE ON A NIGHT CROSS-COUNTRY FLIGHT, THE ENGINE RPM SUDDENLY DROPPED AND HE WAS UNABLE TO MAINTAIN ALTITUDE. HE SQUAWKED 7700 AND ASKED THE FLIGHT SERVICE TO IDENTIFY THE NEAREST AIRPORT. AS THE PILOT APPROACHED THE AIRPORT, HE MADE A THROTTLE REDUCTION AND THE ENGINE QUIT. HE THEN ATTEMPTED AN EMERGENCY LANDING ON A ROAD APPROXIMATELY 1/2 MILE NORTH OF THE AIRPORT. DURING THE ATTEMPT, HIS LEFT WING GRAZED THE ROOF OF A CAR. A POSTACCIDENT INSPECTION REVEALED THAT THE HEAD OF THE NO. 2 CYLINDER EXHAUST VALVE HAD SEPARATED FROM THE STEM.
On April 29, 1995, at 2220 hours mountain standard time, a Piper PA-28-151, N41981, sustained substantial damage during a forced landing at Parker, Arizona. The aircraft was owned and operated by the pilot and was on a personal cross-country flight. Visual meteorological conditions prevailed at the time, and a VFR flight plan had been filed for the operation. Neither the certificated commercial pilot nor his passenger was injured. The flight originated from John Wayne Airport, Santa Ana, California, at 2030 on the day of the accident. The pilot reported that he had climbed to a cruising altitude of 7,500 feet msl, and had switched from the left to right main fuel tank as he crossed Twentynine Palms, California. Shortly thereafter, he heard a change in engine sounds and noticed that the engine tachometer had dropped from 2,200 to 1,700 rpm. He immediately turned on his fuel boost pump, switched back to the left main tank, and advanced his mixture control to full rich. After advancing the mixture, he noticed an even greater drop in rpm. He immediately leaned the mixture and was successful in regaining some engine rpm. He also noticed that the aircraft was descending at a rate of 100 to 200 fpm. He reported that his oil pressure and temperature, as well as his fuel pressure, were all within prescribed operating limits. At 2205, the pilot squawked 7700 and contacted Riverside Flight Service Station (FSS) and reported his position as 44.3 miles from Lake Havasu City, Arizona, and declared an in-flight emergency. He asked the FSS specialist to identify the nearest airport and was advised that the Parker airport was the closest to his reported position. Still losing altitude, the pilot proceeded to navigate toward the Parker VOR with the intention of landing on runway 01 at the Parker airport. As the pilot approached the Parker airport, he activated the runway lighting system and made a throttle reduction. After making the throttle reduction, the engine quit. He attempted to restart the engine, but abandoned the effort after he realized that he no longer had sufficient altitude to reach the airport. Using his landing lights, he attempted to make an emergency landing on a road approximately 1/2 mile north of the airport. During the landing attempt, he overtook a car traveling in the same direction. The left wing of the aircraft grazed the roof of the car as the aircraft touched down. During rollout, the left main gear and nose wheel collapsed. After the collapse of the nose gear, one blade of the propeller was bent aft approximately 45 degrees near the 6 o'clock position. There was no visible damage to the opposite blade. The accident occurred after astronautical twilight and there was no moon illumination. The pilot reported that the aircraft departed with 34 gallons of fuel and 5.75 quarts of oil. When the aircraft was recovered, retrieval personnel drained approximately 6 gallons from the left tank and 12 gallons from the right. A postaccident inspection of the engine was conducted. A continuity check was performed by hand rotating the propeller through a 10-degree arc. Movement was noted in the accessory gears and the vacuum pump shaft. After removal of the rocker box covers, valve action was noted on all four cylinders. The No. 2 cylinder exhaust push rod and push rod tube were bent. The No. 2 cylinder was removed and disassembled. The head of the exhaust valve (with part No. SL745416(Z28)7) was found to have separated at the stem. There were gouges and scarring inside the cylinder and on the piston. There was also a hole in the piston which corresponded in size to the head of the valve; however, the head was not found in the No. 2 cylinder. The oil regulating ring was found stuck in the piston groove and the base of the cylinder was wet with oil. After disassembly of the No. 3 cylinder, fragments of the No. 2 exhaust valve head were discovered. The oil regulating ring was also stuck in the piston groove. Both magnetos were removed and inspected. After a hand rotation of the left magneto, the impulse coupling functioned and all four leads produced a spark. The right magneto was also hand rotated and sparked all four leads. The No. 2 top and bottom spark plugs were removed and found to have impact damage on their electrodes. The No. 1 bottom plug was inspected and was found to be fouled with carbon, and a piece of the No. 2 exhaust valve head wedged next to the electrode. The No. 4 bottom plug was wet with oil.
the failure and separation of the No. 2 cylinder exhaust valve. Darkness was a factor in the accident.
Source: NTSB Aviation Accident Database
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