N345ATPiper PA-28R-200 · 1974

On November 22, 2009, about 1330 eastern standard time, a Piper PA-28R-200, N345AT, was substantially damaged when it impacted trees and terrain during a forced landing near Wappinger, New York. The certificated commercial pilot and the pilot-rated passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which departed Orange County Airport (MGJ), Montgomery, New York, about 1313, and was destined for Danbury Municipal Airport (DXR), Danbury, Connecticut. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91.

According to air traffic control (ATC) information provided by the Federal Aviation Administration (FAA), the airplane departed MGJ and the pilot contacted ATC shortly thereafter to request flight following services. About 1325, the pilot advised the controller, "we've got an oil problem, we're bringing it right to POU [Duchess County Airport, Poughkeepsie, New York]." According to radar data, at that time the airplane was about 6.8 nautical miles south of POU, at an altitude of 3,900 feet msl.

The controller subsequently provided the pilot radar vectors to POU. At 1326, the pilot stated "we just lost the engine." At that time, the airplane was about 5.2 nautical miles south of the airport at 3,000 feet msl. The pilot and the controller then discussed alternative forced landing sites, including a highway that was about 1.5 nautical miles west of the airplane's position. At 1328, the pilot advised that he would not be able to make a landing on the highway, but that he was going to try to make it to an area to his right. Radio contact was lost shortly thereafter and the last radar target was observed 2.5 nautical miles south of POU, at 200 feet msl.

According to FAA records, the pilot held a commercial pilot certificate with ratings for airplane single engine land and sea, and instrument airplane. The pilot reported 1,100 total hours of flight experience on his most recent FAA second-class medical certificate, which was issued on February 4, 2009.

The four-seat, low-wing, retractable-gear airplane, serial number 28R-7435303, was manufactured in 1974. It was powered by a Lycoming IO-360-C1C, 200-horsepower engine. Review of maintenance records provided by the co-owner of the airplane revealed that at the time of the accident, the engine had been operated for about 1,714 hours since its most recent overhaul, which was completed on May 8, 1991, at an aircraft total time of 2,959 hours. The engine was then disassembled and inspected after a sudden stoppage event in May 1993, about 339 operational hours since the overhaul. A work order detailing the inspection, and parts repaired or replaced at the time, noted the installation of eight "SL74309 M03" connecting rod bearings.

The engine was subsequently returned to service in July 1993. Between August 1993 and August 2009, the engine accumulated 1,363 operational hours. During that time, the engine log reflected 19 entries detailing engine oil changes. Of those 19 entries, 6 specifically noted an inspection of the oil filter or suction screen. An entry detailing an oil change completed in November 2004 stated, "Check old filter for metal (found some non-ferrous material) Recommend recheck in 25 hours". The next entry in the engine logbook, dated February 2005 stated, "...cut open oil filter, inspected for contamination none noted." This entry was the last which noted any inspection of the engine oil filter.

The airplane's most recent annual inspection was completed August 1, 2009, at a tachometer time of 1362 hours, and at an aircraft total time of 4,662 hours. The next and most recent entry in the engine logbook was dated September 9, 2009, and logged about 4.8 flight hours before the accident flight, stated "Checked out oil leak and traced to engine driven fuel pump. Replaced fuel pump, washed engine, ran-up and checked for leaks, no leaks were noted. Found ok to return to service."

At 1353, the weather reported at POU included clear skies, 10 statute miles visibility, winds from 010 degrees at 9 knots, temperature 11 degrees Celsius (C), dewpoint 3 degrees C, and an altimeter setting of 30.32 inches of mercury.

The accident site was located in the vicinity of the final radar target, at an elevation of 239 feet, on a densely wooded private lot. The initial impact point was a tree about 60 feet-tall. The wreckage path was oriented about 195 degrees magnetic from the tree, and broken tree branches and small pieces from the airplane were strewn along that path. The main portion of the wreckage came to rest about 190 feet beyond the initial impact point, and consisted of the fuselage, both wings, and the tail section.

The airplane came to rest inverted oriented roughly 230 degrees magnetic. The outboard 4 feet of the left wing was separated from the inboard portion, and was located about 15 feet from the left wing. Control continuity was traced from the cockpit area to the respective flight control surfaces. All three landing gear were in the down and locked position, though the landing gear selector handle was found in the up position. The flaps were set to the 10-degree position. The stabilator trim tab was deflected toward the nose up direction. Both fuel tanks were ruptured, and there was a strong odor of fuel at the scene. No oil staining or spray patterns were noted on the outside of the fuselage, and no evidence of a pre- or post-impact fire were noted.

One of the two propeller blades was bent aft about 16 inches from the tip, but otherwise appeared relatively un-damaged. The other propeller blade appeared straight and also was relatively un-damaged. The propeller remained attached to the propeller flange on the crankshaft. The engine displayed varying degrees of impact damage, and continuity of the drivetrain was confirmed from the accessory section to the propeller.

A cursory examination of the engine was conducted after the engine was separated from the airframe and placed on a trailer for transport. Oil was observed draining from the engine as it was separated from the airframe and transported away from the scene. The engine oil filler cap remained installed, though the filler neck was separated from the engine case, consistent with impact. The top four spark plugs were removed, and three appeared dark gray in color with no abnormal wear noted, while the fourth spark plug appeared oil soaked.

The oil suction screen was removed, and was found to be contaminated with ferrous and non-ferrous metal, as was the oil filter element. The engine was retained, and a more detailed inspection was scheduled for a later date. An electronic engine monitoring instrument was recovered from the wreckage and forwarded to the NTSB Vehicle Recorders Laboratory, Washington, DC, for data extraction.

The wreckage was transported to an aircraft recovery facility where the engine was disassembled and examined in detail. As the engine was disassembled, an undetermined quantity of oil drained from the crankcase. No damage was noted to the rear accessory gears, intake or exhaust valves, valve springs, or valve rockers. The engine oil pump was disassembled, and light radial scoring was noted on the pump cavity walls, while the pump impeller gears were intact.

The number 1 and 2 cylinders were removed with no damaged noted to the pistons. The corresponding connecting rods were free to move on the crankshaft journals. Removal of both connecting rods revealed that the connecting rod bearings were intact and exhibited some pitting and embedded material. The number 3 and 4 cylinders could not be separated from the crankcase due to damage at the cylinder bases inside the crankcase. The number 4 connecting rod remained attached to the crankshaft and was free to move, while the number 3 connecting rod was separated from the crankshaft.

Portions of the number 3 connecting rod, connecting rod cap, and connecting rod cap bolts were found in the oil sump, along with other debris. A complete connecting rod bearing for the number 3 connecting rod was not found. The number 3 connecting rod journal exhibited a grove around its circumference consistent in profile with a connecting rod bolt shank. The journal also exhibited thermal bluing. The crankcase, crankshaft, number 3 and 4 cylinders, and the debris found within the engine were forwarded to the NTSB Materials Laboratory for further examination.

An autopsy was performed on the pilot by the Office of the Medical Examiner, Dutchess County, New York. The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on the pilot. No traces of carbon monoxide, cyanide, or ethanol were detected.

A detailed metallurgical examination of the engine was conducted by the NTSB Materials Laboratory. According to the Materials Laboratory Factual report, the main crankcase journals 1, 2, and 4, and connecting rod journals 1 and 2 were smooth to the touch and did not show any significant scoring when scraped with a fingernail across the journal surfaces. The number 3 connecting rod journal showed rotational scoring, heat tinting, and metal transfer on the surface around the diameter. Some rotational scoring was also observed on main crankcase journal 3. A semicircular wear groove was observed in the middle of the journal surface extending around the circumference of the number 3 connecting rod journal. The bore of the connecting rod saddle exhibited heat tinting with circumferential sliding contact marks and metal transfer. The middle of the bore was raised relative to the rest of the surface corresponding to the wear location on the journal.

The number 3 connecting rod was fractured in the saddle at two places. Portions of the fracture surfaces showed relatively smooth flat features with curving boundaries, features consistent with fatigue. Fatigue features emanated from origin areas located at the upper and lower surfaces. Post-fracture contact damage was observed at the origin areas on the upper side of the connecting rod saddle. The recovered pieces of the number 3 connecting rod cap, along with the associated attachment bolt and nut pieces showed substantial post-fracture contact damage. Circumferential sliding contact marks were observed on the bore surfaces. The fractured ends of the connecting rod bolt pieces showed curving crack arrest lines consistent with cyclic loading during fracture. However, fracture features on both surfaces were relatively rough consistent with relatively high stresses during cracking.

The number 4 connecting rod was cut at the split line to facilitate examination of the bearings. Bearing surfaces were dark gray with a slight speckled appearance. Isolated small pits were observed on the bore of the saddle side bearing consistent with some embedded debris. Rubbed areas were also observed in a few areas near the forward and aft edges of the bearing. The bearing edge was displaced outward in an area where the cap was damaged by contact with another object.

The installed connecting rod bearings were marked with the part number SL74309 M03, consistent with Federal Aviation Administration Parts Manufacturing Authority components manufactured by Superior Air Parts of Dallas, Texas. The inner diameters of the SL74309 M03 bearings were 0.003 inches less than the standard size part number SL74309 bearings. The number 1 and 2 connecting rod journal diameters were measured using a micrometer. The number 1 and 2 connecting rod journal diameters measured 2.2469 inches and 2.2468 inches, respectively. The measured diameters were compared to engineering drawings for the crankshaft provided by Textron Lycoming, and the journal diameters were within a range that was 0.003 inch less than the as-manufactured specifications.

Metal pieces consistent with bearing material recovered from within the crankcase and oil sump were examined, and generally had a mix of grey and blue/brown tints. Some pieces showed sliding contact marks, while others showed a rippled surface often in a slight arc and often with a folding-fan-shaped wrinkle pattern.

Engine Monitoring Unit Non-Volatile Memory

A J.P. Instruments EDM-700 engine monitoring unit was recovered from the wreckage. The unit was forwarded to the NTSB Vehicle Recorders Laboratory and its non-volatile memory was downloaded. The unit recorded parameters associated with the engine including cylinder head and exhaust gas temperatures for cylinders one through four, oil temperature, outside air temperature, and battery voltage. A record of all parameters was logged every six seconds, with a total of 13,293 total records. These records covered numerous flights, including the accident flight, which was recorded in the final 256 records of data, for a total duration of 0:26:36 (hours : minutes : seconds).

According to the data, about 9 minutes after data began recording for the flight, the exhaust gas temperature of all four cylinders increased from roughly 1,000 degrees Fahrenheit (F) to 1,330 degrees F over about 30 seconds, and was consistent with the takeoff and initial climb for the flight. The oil temperature climbed gradually from the beginning of the recording before stabilizing around 200 degrees F, about 4 minutes after the takeoff. About 5 minutes later, the oil temperature began increasing until 0:22:36 when it peaked at 259 degrees F. About this time, the battery voltage dropped from 14.3 volts to 12.4 volts. The voltage remained below 12 volts for the remainder of the flight, and all temperature parameters began decreasing after that point.

Australian Airworthiness Bulletin

On April 4, 2006, the Civil Aviation Safety Authority of Australia issued an Airworthiness Bulletin, AWB 85-1, which detailed some of the reasons behind and steps to minimize bearing failures in Lycoming engines. The bulletin listed several factors that may lead to bearing failure, including but not limited to: inadequate supply of oil, inadequate or excessive bearing clearances, high oil temperature, propeller strike, or failure to pre-oil the engines following an engine change or prolonged period of inactivity. The bulletin also recommended several operational and maintenance procedures to help identify signs of an impending failure. These included recommendations to maintenance personnel to change the oil and filter per the provisions of guidance published in Lycoming service bulletins, and that cutting open and inspecting the contents of the oil filter may provide valuable information on bearing condition. It also recommended pre-oiling of the engine per the provisions of guidance published in Lycoming service instructions. Finally, the bulletin recommended that operators follow correct cold weather engine start procedures, and report all instances of engine malfunction, parameter exceedance, or propeller strike to ensure timely maintenance action.

Manufacturer Maintenance Information

The Piper Cherokee Service Manual detailed maintenance procedures applicable to the accident airplane. The manual stated that aircraft engines equipped with full flow oil filters should have those filters replaced after each 50 hours of engine operation. Further, the manual advised that before discarding the used filter, the paper element should be removed and examined for evidence of internal engine damage such as "chips or particles from bearings." The section concluded that evidence of internal engine damage found in the oil filter justified further examination to determine the cause.

Lycoming Service Bulletin Number 480E, applicable to all Lycoming direct drive engines, provided recommendations for oil and oil filter change intervals, as well as filter content inspection. The bulletin provided guidance congruent with that detailed in the Piper Cherokee Service Manual.