DOVER, DE, USA
N3506A
Piper PA-22-135
The pilot stated that shortly after takeoff, as the airplane climbed through about 130 feet AGL, the engine lost power. He attempted to make an emergency landing in a nearby open field but struck a power line and nosed over, coming to rest inverted in the field. The pilot stated that the terrain surrounding the airfield contained obstacles and power lines. Postaccident examination of the engine revealed that the center main crankshaft bearing had spun. Examination of the mating surfaces around the bolt holes, and on both halves of the engine block center main bearing caps revealed evidence of fretting. The engine manufacturer stated that improper torque of the main bearing through bolts would result in fretting. Maintenance records indicate that the engine was overhauled in March 1989, and had accumulated 105 hours at its most recent annual inspection on 8/21/95.
HISTORY OF FLIGHT On April 19, 1996, at about 1930 eastern daylight time, a Piper PA-22-135, N3506A, experienced a loss of engine power shortly after takeoff at the Chandelle Estates Airport, near Dover, Delaware. The pilot and the one passenger sustained serious injuries. The airplane sustained substantial damage when it struck power lines during the ensuing forced landing. Visual meteorological conditions prevailed. The local flight was conducted under 14 CFR Part 91, and originated from Dover, Delaware, at approximately 1928. The pilot stated that he had owned the aircraft for about 12 years, and had logged about 400 hours in the accident make and model airplane. He said that the flight during which the accident occurred was intended as a pleasure flight. The pilot reported that he noted no anomalies during the preflight inspection of the airplane. He said he taxied the airplane on the right fuel tank and performed an engine run up before takeoff. He stated that the engine run up revealed no anomalies. He reported that he set the flaps to the first notch, checked the fuel quantity gauges, selected the left fuel tank, and prepared for takeoff. The pilot stated that the takeoff ground roll appeared normal. He reported that at about 60 miles per hour (MPH), he rotated, and the initial climb out was normal. The pilot stated that he retracted the flaps as the airplane climbed through about 100 feet above ground level (AGL). He reported that the airplane was at about 130 feet AGL when he noticed that the revolutions per minute (RPM) had dropped from about 2350 to about 1500 RPM. The pilot stated that he "...initiated a turn towards [a] field and during the turn the engine quit." The pilot reported that he tried to restart the engine, but was not successful. He stated that, as the airplane descended, "...it became obvious that I was not going to clear [the power lines]... ." He stated that he added full flaps in an attempt to avoid the power lines, but the airplane struck the wires, and came to rest in a field. The passenger stated that he occupied the right front seat of the airplane for the local, pleasure flight. He said that he did not notice anything out of the ordinary during the engine start, taxi, takeoff roll, or initial climb. He reported that he noticed that the indicated airspeed was about 85 mph when the engine lost power. The passenger stated that the engine did not "...spit or sputter..." and the propeller did not windmill. He said the pilot turned right and extended the flaps in an attempt to fly over some power lines, to make a forced landing in a field. The passenger reported that the airplane struck the wires, nosed into the ground and flipped onto it back. He stated that he believed he lost consciousness for a little while, and the next thing he was aware of, the pilot was yelling at him to get out. The pilot and the passenger reported that they could hear and smell fuel leaking from the fuel tanks as they exited the airplane. The pilot stated: "The airfield is surrounded by obstacles on four sides and powerlines on three. Without powerlines, I would not have crashed." WRECKAGE EXAMINATION/DOCUMENTATION The aircraft was found in a hangar, with the engine attached to the airplane and resting on a metal drum. The main landing gear were intact and undamaged, however, the nose gear was found collapsed aft. The leading edge of the left wing was damaged to about three feet inboard of the wing tip and the flaps were found extended to 40 degrees. The vertical stabilizer was crushed about 4 inches from the top. All of the flight control cables and pulleys were damaged in the cockpit area however, continuity was established throughout the rest of the airplane. Rudder, elevators, ailerons, flaps and elevator trim all appeared capable of normal operation. Recovery personnel reported that both seats were removed during the recovery operation. They stated that the seats had come loose during the accident. Examination of the two seats found no structural damage to their attachment points to the cockpit. The seatbelts remained attached to their points in the cabin and appeared undamaged. The cockpit floor was distorted and pushed up into the cabin. The rudder peddles on both sides were distorted as well as the control yokes. The cockpit instrument panel exhibited 2 to 3 inches of crush on the left side. Examination of the ignition/magneto switch found it set to the BOTH position, with the key broken off in the on position. A functional test of the switch revealed that it was capable of normal operation. The left magneto was removed and examined, the following was placard on the side of the magneto housing: Mfg. Bendix, Type S4LN-21, SN: 801211, PN: 10-51360-37. The magneto was tested and appeared capable of normal operation. The right magneto was removed and examined, the following was placard on the side of the magneto housing: Mfg. TCM Factory A/C Products Division, Type S4LN-20, SN: H228705DR, PN: 10-51350-29. The magneto was tested and appeared capable of normal operation. The carburetor was found separated from the engine and was void of fuel. The engine was removed from the airframe for further examination and teardown. The propeller flange was found broken and one propeller blade tip was bent aft. Examination of the engine block found no evidence of impact damage, however the propeller could not be rotated. On May 15, 1996, the engine was boxed and shipped to the Textron Lycoming facility in Williamsport, Pennsylvania. On June 12, 1996, the box was opened and the engine was disassembled. Internal examination of the engine block found that the center main bearing had spun on the crankshaft. Examination of the mating surfaces around the bolt holes and on both halves of the engine block center main bearing caps, revealed evidence of fretting. The manufacturer's representative stated that an improper torque value used on the center main bearing through bolts would result in fretting and subsequent failure of a main bearing. No other discrepancies were noted during the disassembly. A review of the maintenance records found that the engine was overhauled in March of 1989. According to the engine logbook, the engine had accumulated a total of 105 hours at the most recent annual inspection, dated August 21, 1995.
the overhaul maintenance personnel's improper major overhaul procedure (improper torque on the engine block center through bolts), which resulted in an in flight loss of engine power. A related factor was the lack of suitable terrain available for a forced landing.
Source: NTSB Aviation Accident Database
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