Hilliard, FL, USA
N2938R
PIPER PA-28R-200
Approximately 2 hours into the cross-country flight the pilot heard a loud noise from the engine compartment and the engine subsequently failed. The pilot performed a forced landing in a field and the empennage struck a tree, resulting in substantial airframe damage. Examination of the engine revealed that the No. 3 cylinder partially separated in flight, resulting in the engine failure. An engine cylinder attachment stud and nut were found at the run-up pad at the departure airport. Examination of the stud revealed evidence of fatigue cracking, which was indicative of an under torque condition. Other cylinder attachment nuts on the engine showed evidence of under torquing. The pilot had recently purchased the airplane and the seller reported that an oil leak was noted during the "pre-buy" inspection. The mechanic who inspected the airplane at the pre-buy reported that two cylinders were leaking oil. The seller installed the cylinders as part of a major overhaul that occurred approximately 131 hours prior to the accident. The pilot did not have maintenance performed to address the cylinder oil leaks prior to the accident.
On April 23, 2009, about 1500 eastern daylight time, a Piper PA-28R-200, N2938R, was substantially damaged following a forced landing and impact with a tree near Hilliard, Florida. The airplane was registered to and operated by the pilot. The certificated private pilot and three passengers were not injured. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight originated at the Dallas Bay Sky Park Airport (1A0), Chattanooga, Tennessee, at 1245. The pilot reported that the flight to Winter Haven, Florida, was uneventful until in the vicinity of Hilliard, Florida. While gradually climbing to 9,500 feet mean sea level, he heard a "loud bang" in the engine compartment. The propeller started to slow and he contacted Jacksonville Center for assistance. The pilot requested the nearest airfield, and Jacksonville Center provided vectors to Hilliard Airpark (01J), Hilliard, Florida. The engine came to a complete stop and the pilot was unable to glide to 01J. The pilot selected an area for a forced landing. During the landing, the tail of the airplane collided with a tree, separating it from the fuselage. After the airplane came to a stop, the pilot removed the engine cowl and he observed one of the cylinders had separated from the crankcase. An inspector from the Federal Aviation Administration (FAA) visited the accident site and examined the wreckage. He reported that there was sufficient fuel in both fuel tanks. The No. 3 cylinder was separated from the crankcase, the corresponding connecting rod was separated from the crankshaft, and the cylinder attachment studs were broken. There was structural damage to the empennage. After the wreckage was recovered to a salvage facility, the engine was again examined. An FAA inspector found that the nuts on four engine cylinder through bolts and two cylinder attachment studs had "torque values lower then [sic] what is called for by the engine technical manual." The pilot later reported that an airport employee at the departure airport found a broken engine cylinder attachment stud and nut on the ground at the engine run-up area. The pilot forwarded the parts to the NTSB investigator-in-charge (IIC) for examination. The cylinder stud and attachment bolt were sent to the NTSB Materials Laboratory for examination. Bench binocular microscope examination of the fractured portion of the cylinder stud revealed the fracture face contained crack arrest marks typical of fatigue cracking that emanated from multiple origins at the root portion of the threads. The origin of the fatigue cracks contained no evidence of corrosion or mechanical damage. The pilot purchased N2938R on December 5, 2008. According to the maintenance records, the previous owner, who was also a certificated airframe and powerplant mechanic, performed a major overhaul of the engine per a logbook entry dated July 8, 2008. The previous owner reported that he installed the cylinders as part of the major overhaul and used a calibrated torque wrench during the installation. At the time of the accident, the airplane had been operated approximately 131 hours since the engine overhaul. The pilot reported that the only maintenance performed on N2938R, after the airplane was delivered to him, was the replacement of an engine starter ring gear. The previous owner reported in a telephone interview that he delivered the airplane to the pilot in December, 2008. During the sale transaction, he reported that the pilot had a mechanic present to perform a pre-buy inspection of the airplane. The mechanic noted a suspect oil leak on the right, rear cylinder (the cylinder closest to the front passenger seat). The mechanic recommended removing and replacing the cylinder base o-ring and the buyer was adamant that this repair be made prior to the sale. The previous owner stated that he paid for the repair by an adjustment to the sales price of the airplane. He did not observe the repair. He later provided a copy of the aircraft purchase agreement that had the following hand-written note at the bottom of the first page: "On delivery of Aircraft, purchasers mechanic found signs of an oil leak @ cylinder bases and recommended replacing seals. Seller agreed to pay $250.00 to have purchasers mechanic replace cylinder o-rings." The mechanic, who assisted the pilot with a pre-buy inspection of N2938R, was interviewed by the NTSB IIC by telephone. He recalled that two engine cylinders were leaking oil around the bases of the cylinders, however he could not recall which cylinders they were. He did not recall anything else remarkable about the condition of the airplane. He advised the pilot that the leaking cylinders would have to be removed to repair the leaks and that he should "talk the guy down five or six hundred dollars" on the sales price of the airplane. He also advised the seller of the cylinder leaks. He stated that the seller responded with, “All engines leak a little bit.” He stated that he then told the seller that a newly-overhauled engine should not leak oil. The 1456 weather observation for Jacksonville, Florida (JAX), located about 16 miles southeast of the accident site, included the following: few clouds at 4,000 feet, scattered clouds at 18,000 feet, surface winds from 280 degrees at 8 knots with gusts to 15 knots, 10 statute miles visibility, temperature 30 degrees Celsius, dew point 12 degrees Celsius, and an altimeter setting of 30.17 inches of mercury.
A total loss of engine power due to the fatigue failure of the No. 3 cylinder attachment stud as a result of insufficient torque during installation. Contributing to the accident was the pilot’s operation of the airplane with a known mechanical deficiency.
Source: NTSB Aviation Accident Database
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