Accident Overview
On February 19, 2017, at approximately 1000 eastern standard time, a Piper PA-28R-200, registration N15745, sustained substantial damage during a forced landing to a road in Bayonne, New Jersey. The private pilot was seriously injured. The airplane was registered to and operated by a private company. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight that departed Republic Airport (FRG) in Farmingdale, New York, about 0900. The flight was conducted under 14 Code of Federal Regulations Part 91.
Pilot Statement
The pilot reported that he had not flown since August 2016 and was taking the club-rented airplane—which he had previously trained in and flown—for a pleasure flight. He conducted a preflight inspection and confirmed that both fuel tanks were topped off and added 1 quart of oil for a total of 7 quarts. After taxiing and performing an engine run-up, he departed. The flight was uneventful until he approached the Statue of Liberty and Verrazano Bridge. Without warning, he heard a "foomph" noise from the engine and saw a white mist that appeared for less than a second and did not return. The pilot realized the engine had lost power (he could not estimate how much) and had trouble maintaining altitude. He attempted troubleshooting: switching fuel tanks from left to right, checking ignition, and glancing at the engine gauges. He recalled the manifold pressure was "all the way up" but did not remember other gauge indications. He moved the propeller lever full forward and declared a "May Day" over the radio. The pilot stated that the engine never lost full power. He declared an emergency, flew toward land, and performed a forced landing to a road. The airplane struck power lines and vehicles before coming to rest on a sidewalk in a congested city neighborhood. There was no post-impact fire or injuries to anyone on the ground. The airplane sustained substantial damage to the wings, tail section, and fuselage.
Engine Examination
The engine was separated from the airframe for examination. The valve covers were removed, and oil was noted throughout the engine. About 0.5 ounce of fuel was recovered from the fuel servo, and 0.25 ounce from the engine-driven fuel pump; the fuel was blue, clear, and consistent with 100-low-lead aviation gasoline. When the engine-driven fuel pump was actuated by hand, suction and compression were confirmed at the inlet and outlet ports. The oil suction screen was removed and contained some metallic contamination. The oil filter was opened and also contained metallic contamination. A timing check of the magnetos revealed they were near their specification of 20° before top dead center. Both magnetos produced spark at all leads when rotated by hand. The top spark plugs were removed, and their electrodes were intact. When the propeller was rotated by hand, camshaft, crankshaft, and valve train continuity were confirmed to the rear accessory section. Thumb compression was attained on cylinders No. 1 and No. 4. The No. 2 cylinder was impact-damaged, and the No. 3 cylinder exhibited a small hole near the intake manifold. Removal of the No. 3 cylinder revealed that the intake valve had separated; the valve stem was recovered in the oil pan, and the remainder of the valve was recovered from its intake manifold. Further examination of the engine case showed that all eight hydraulic valve tappet plungers were installed 180° opposite from proper installation per the manufacturer's overhaul manual.
The No. 3 cylinder assembly, including the fractured intake valve, was examined at the National Transportation Safety Board Materials Laboratory in Washington, DC. The examination showed that the intake valve was fractured in the stem in two places and through the head in one place. The interior of the cylinder exhibited damage consistent with impacts from the fractured valve. The connecting rod was intact, but the bearings were worn through both the babbit and copper layers. Examination of the fracture surfaces revealed fatigue cracks initiating from the fillet radius between the valve stem tip and the key area of the stem shaft; other fractures were consistent with overstress.
Maintenance History
A review of the aircraft maintenance logbooks revealed that the engine was repaired about 35.7 hours before the accident, on January 9, 2017. At that time, all four cylinders were removed and reinstalled, including the hydraulic valve tappet assemblies for each cylinder. According to the entry, the mechanic wrote, "All work performed I/A/W Lycoming overhaul and service manuals as well as Piper service manual. Aircraft approved for return to service." The Lycoming Direct Drive Engine Overhaul Manual (pages 6-7 and 6-8) discusses the hydraulic valve tappet assemblies along with an illustration (Figure 6-9) depicting how the tappet plungers should be oriented once installed in the engine.