Aviation Accident Summaries

Aviation Accident Summary NYC97LA024

MYERSTOWN, PA, USA

Aircraft #1

N394PM

Piper PA-46-350P

Analysis

During the climb after takeoff, between 3,500 and 4,000 feet, the pilot noticed the engine oil pressure decreasing and the oil temperature increasing. The pilot advised the controller that he was experiencing a problem, and he was provided radar vectors to the nearest airport. During vectors, the engine failed, and oil covered the windshield and pilot's side window. Unable to see the airport, the pilot completed a forced landing to an open field, where the airplane impacted the ground. The engine had accumulated about 440 hrs of flight time, since it was last overhauled (by the manufacturer). Investigation revealed that remanufactured connecting rods had been installed. Examination of the engine revealed four of the six connecting rod bearings had melted at the crankshaft, and fatigue cracks were found on the number four connecting rod and end cap. When the connecting rod end cap retaining nuts were removed, rings of moderate wear and fretting were found in the nut recesses where the nuts contacted the rods.

Factual Information

On December 2, 1996, at 1521 eastern standard time, a Piper PA-46-350P, N394PM, was substantially damaged during a forced landing near the Decks Airport, Myerstown, Pennsylvania. The certificated private pilot received serious injuries. Visual meteorological conditions prevailed for the personal flight that originated at Harrisburg, Pennsylvania, about 1508. A visual flight rules flight plan had been filed for the flight conducted under 14 CFR Part 91. In the NTSB Form 6120.1/2, the pilot/owner stated that he flew an uneventful proficiency flight from Somerset, New Jersey, to Harrisburg. After landing, without shutting the engine down, he received taxi and flight following instructions for a return flight to Somerset. During the climb after takeoff, between 3,500 and 4,000 feet, the pilot noticed the engine oil pressure decreasing, and the oil temperature increasing. The pilot advised the controller that he was experiencing a problem, and after a discussion with the controller, he was provided a heading to the Decks Airport. The pilot further stated: "...He vectored me toward the Decks Airport and about the time I made the turn to the proper heading, the engine stopped running and oil was thrown on the left windscreen. I was having trouble seeing. The only thing I was able to see in front of me was a row of houses. I looked out the right side window and saw a field and I decided I would try to put the plane down on the field..." Several witnesses observed the airplane near the Decks Airport. Three of the witnesses stated that they observed the airplane heading east, about 2 miles south of the airport, at 3,000 feet. They observed white smoke trailing the airplane. The airplane made an abrupt turn to the north, and when the airplane was about mid-field, black smoke was observed trailing the airplane. The witnesses further stated: "...At that time he made a hard left turn toward the southwest, the engine had locked-up and the gear was down. It appeared that he was trying to make the field but could not. He stalled the airplane approximately 40 feet above the ground at which time the right wing dropped. Then he impacted the ground..." On January 8, 1997, the engine was disassembled at Executive Air, Hagerstown, Maryland. Present during the examination was the NTSB investigator-in-charge, and parties to the investigation. The engine examination revealed that the numbers one, two, and five connecting rod ends and bearings had melted from the crankshaft. The number six connecting rod crankshaft bearing was melted to the crankshaft. The number three connecting rod rotated freely on the crankshaft; however, when disassembled, the bearing was worn and grooved. The number four connecting rod crankshaft bearing was broken in several pieces and partially melted to the crankshaft. The numbers three and four connecting rods and bearings were removed for further examination. Several pieces of metal were found in the valve covers of the numbers two, four, and six cylinders. The suction oil screen was packed with metal particles similar to the connecting rod ends. Large quantities of metal particles were also found in the oil filter, lines and sump. One turbo charger rotated freely. The other turbo charger contained caked mud. When the mud was removed, the turbo charger rotated freely. NTSB Materials Laboratory The connecting rod components were sent to the NTSB Materials Laboratory Division for examination. The Metallurgist's Factual Report addressed the number four connecting rod. The report stated: "...fractures were located at the machined recess for the rod bolt nuts. Optical examinations revealed features indicative of fatigue progression along two fronts for each fracture...fatigue fronts initiated at multiple origins on the machined sides of the nut recess...fatigue fronts initiated at the corners between the recess and the exterior surface of the rod...The rod cap was transversely fractured approximately equidistant from the split line faces...Optical examination of the fracture showed characteristics of multiple independent fatigue cracks emanating from the bearing surface..." The Metallurgist's report also stated: "...the rod bolt nuts were cut and removed...Visual examination found moderate fretting and some galling on the contact faces...With the nuts removed, rings of moderate wear and fretting were noted in the nut recesses where the nuts contacted the rods..." Engine History The Lycoming engine installed in N394PM had been overhauled by Textron-Lycoming, on September 25, 1995. The Lycoming certificate in the engine log book stated, "...All parts have been inspected and have been determined airworthy to return to service..." The engine was installed with zero total time. At the time of installation a new oil cooler, oil cooler hoses, and oil filter were also installed. The engine examination revealed that the connecting rods were stamped with "-85." According to the Lycoming investigator, the -85 represented remanufactured parts. The engine had accumulated about 440 hours since installation. The engine log book revealed that the engine oil had been changed on the average about every 18 hours for the first 100 hours of operation, and every 27 hours for the next 350 hours. Fuselage The airplane fuselage was also examined on January 8, 1997. An oil coating obstructed vision out the front windshield and pilot's side window. The examination also revealed that the pilot's shoulder harness reel and attachment bracket had separated from the fuselage. This accident, and another fatal PA-46 accident, were review with the New Piper Aircraft, Inc. As a result of the information, the New Piper Aircraft, Inc., issued a PA-46 service bulletin for a shoulder harness mounting bracket replacement kit.

Probable Cause and Findings

fatigue failure of the connecting rod to crankshaft attachments, due to inadequate overhaul of the engine by the manufacturer, which resulted in a loss of engine power and a forced landing. Factors relating to the accident included the discharge of oil from the ruptured engine, which subsequently obstructed the pilot's view through the windshield and side window, preventing him from having an unobstructed view of the emergency landing area.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports