NYC08LA245

Approximately 2 weeks before the accident, significant unplanned maintenance was performed on the radial engine of the aerial application airplane. The activity included the removal of seven of the nine cylinders to remove fragments of piston rings, a piston skirt, and a broken governor drive gear from the engine case. Six of the removed cylinders were re-installed, and one cylinder was replaced with an overhauled cylinder and a new piston. The airplane was test flown, returned to service, and utilized for several days. On the day of the accident, one witness said that the engine was making "popping" noises before it crashed. The airplane touched down in a small clearing, but nosed over and collided with shrubs and trees. The accident site was located between the field being sprayed and the owner's airstrip. The pilot was fatally injured. Post-mortem toxicology revealed evidence of recent use of several over-the-counter, and one prescription, medications, but these medications are not typically associated with impairment. An autopsy revealed the presence of severe coronary artery disease and heart enlargement. The pilot’s physique and heart enlargement also strongly suggested that he may have suffered from obstructive sleep apnea, a condition associated with increased accident risk, but the circumstances of the accident were not consistent with impairment or incapacitation. Post accident examination of the engine revealed internal damage consistent with the engine being operated with one or more loose metallic items inside the engine case, but the damage could not be directly associated with the engine power loss. Several piston ring fragments were recovered from the engine case, but it could not be determined whether they were vestiges of previous problems, or were portions of the rings recently installed. No specific engine failure cause or mode was identified during the investigation.

History of flight

On July 12, 2008, about 0959 eastern daylight time, a Grumman G-164A, N7395, was substantially damaged when it impacted terrain in Pelham, Georgia. The certificated commercial pilot was fatally injured. The aerial application flight was operated under the provisions of 14 Code of Federal Regulations (CFR) Part 137. Visual meteorological conditions prevailed for the flight, and no flight plan was filed.

On June 28, 2008, the pilot reported propeller control problems with the airplane, and the next day, a mechanic from Florida drove to Pelham to perform maintenance on the engine. The maintenance was completed on July 2, and the pilot began using the airplane again that same day. Investigators could not ascertain how many flights or engine hours the airplane accrued between July 2 and July 12.

On the morning of the accident, one witness who was located approximately 2 3/4 miles north-northwest of the accident site, said that as the airplane flew past her, it sounded like a helicopter, and that the engine was making "popping" noises. Another witness who was working in a field near a pond, observed the airplane circle the pond twice before he saw it "go down." The witness headed towards the presumed impact location, saw that the airplane "had crashed," and that it was on fire. The witness then notified local emergency authorities.

Personnel information

Pilot

According to FAA records, the pilot held a commercial pilot certificate with airplane single and multi-engine land ratings. He was prohibited from carrying passengers for hire at night, or on cross-country flights of more than 50 nautical miles. The pilot reported 24,800 total hours of flight experience on his most recent second-class medical certificate, which was issued in August 2007. The pilot was also the owner of a company that was certificated for aerial agricultural application under 14 CFR Part 137. The certificate was issued in July 1989, and the most recent validation date for the certificate was June 2008.

Engine Mechanic

The mechanic who performed the last known maintenance activity on the engine held a mechanic's certificate, with airframe and powerplant ratings. He was employed by a maintenance provider in Florida that specialized in servicing the aerial application industry, and Pratt & Whitney radial engines. The mechanic had been employed by this organization for at least 10 years. He was also a personal and professional acquaintance of the pilot for approximately 40 years.

Aircraft information

The accident airplane was manufactured in 1972. Maintenance records indicated that a major overhaul was conducted on the Pratt & Whitney R-1340 engine in July 2005, and the corresponding logbook entry listed the time since major overhaul (SMOH) as "00:00" hours. This engine remained installed in the airplane until the accident.

In September 2005, with an engine SMOH of approximately 202 hours, the number two cylinder was removed to conduct maintenance on the exhaust valve guide, and the cylinder was then re-installed on the engine. In October 2005, with an engine SMOH of approximately 300 hours, the number three cylinder was removed due to a crack, and was replaced with an overhauled cylinder. In March 2006, with an engine SMOH of approximately 383 hours, the number three cylinder was again removed and replaced with an overhauled cylinder.

Between August 9 and December 29, 2005, the maintenance records indicate that the oil was drained, and the oil screens were checked for contamination, on four separate occasions. These occurred at approximately 38, 101, 193 and 382 hours SMOH, respectively. The next documented oil drain and screen check occurred on April 27, 2008, at an SMOH of 601 hours. No contaminants were noted in any of the corresponding log entries.

Maintenance records documented two annual inspections since the installation of the accident engine. The first was on March 7, 2006, and the second was on May 2, 2008. The SMOH times for these inspections were 383 and 601 hours, respectively.

The last known engine maintenance was completed on July 2, 2008. According to the mechanic who conducted the maintenance, he was based approximately 130 miles from the airstrip where the airplane was located, which was also where the maintenance was conducted. The maintenance was conducted outside, and on occasion had to be suspended for inclement weather.

The maintenance activity included the removal of seven of the nine cylinders; cylinders two and seven were not removed. During the maintenance activity, fragments of piston rings and a piston skirt, as well as a broken governor drive gear, were discovered in the engine case. The engine was pressure-cleaned with mineral spirits and reassembled. Six of the removed cylinders were re-installed with "serviceable" pistons, and the number one cylinder was replaced with an overhauled cylinder and a new piston. The airplane was successfully test flown after the maintenance was completed.

The airplane was first registered to the accident pilot in April 2008.

Meteorological information

The 1000 surface weather observation at an airport located approximately 30 miles east of the accident site reported winds from 350 degrees at 5 knots, visibility 10 miles, scattered clouds at 1,300 feet and 1,800 feet, broken clouds at 8,000 feet, temperature 26 degrees C, dew point 22 degrees C, and an altimeter setting of 30.13 inches of mercury.

Wreckage and impact information

The accident site was a small grassy clearing in a wooded area, located approximately 6/10 of a mile north-northwest of the private airstrip where the airplane was based, and along a course between the field which had been sprayed and the airstrip. The first ground scars were two parallel scrapes approximately 13 feet long and 6 feet apart. These scars were oriented on a southeast heading. The second and last prominent ground scar began 17 feet beyond the end of the parallel scrapes. It was approximately 8 feet wide and 14 feet long. Numerous small airplane fragments were distributed in the proximity of the ground scars. The majority of the wreckage was tightly contained at the base of the trees that bounded the clearing, approximately 16 feet beyond the end of the second ground scar.

The airplane came to rest inverted, facing back towards the debris path and ground scars. The wings were partially separated from the fuselage, and the forward fuselage exhibited significant crushing and other distortion. The wreckage exhibited considerable fire damage. Flight control continuity was not verified on scene. The engine was mechanically separated from the fuselage, but remained with the wreckage. The propeller remained attached to the engine. Both propeller blades were bent aft. The engine and airframe were retained for additional examination.

Medical and pathological information

The pilot did not indicate the use of any medications, or the diagnosis of any medical conditions, on his most recent application for his FAA second-class medical certificate, which was dated August 2, 2007. On that application, his height was noted as 72 inches, and his weight was noted as 278 pounds.

Toxicological testing was conducted by the FAA Civil Aero Medical Institute (CAMI). Test results were negative carbon monoxide, cyanide, or ethanol. The testing detected Meteprolol in the pilot's blood, and Ephedrine, Meteprolol, Naproxen, Pseudoephedrine and Salicylate in the pilot's urine.

An autopsy was performed by a medical examiner from the Georgia Bureau of Investigation. The cause of death was noted as "Traumatic injuries complicating cardiomegaly and coronary atherosclerotic disease." The autopsy noted that "the heart is enlarged and weighs 540 grams. The chambers of the right side of the heart are dilated. … The myocardium exhibits gray-white scarring involving the apical region of the anterior left ventricle.