Aviation Accident Summaries

Aviation Accident Summary DFW06LA078

Fittstown, OK, USA

Aircraft #1

N18045

Cessna C-37

Analysis

The airline transport pilot (ATP) flying a 1937 vintage tailwheel-equipped airplane collided with trees and terrain during a forced landing following a loss of engine power shortly after departure from the pilot's private grass airstrip. The single-engine airplane was destroyed in a post impact fire. An examination of the vintage radial engine revealed a cracked cylinder head and "blow torching" through the exhaust valve port.

Factual Information

On March 6, 2006, at 1234 central standard time, a vintage Cessna C-37 single-engine airplane, N18045, was destroyed during a forced landing following a loss of engine power during initial takeoff climb after departing from a private airstrip near Fittstown, Oklahoma. The airline transport rated pilot, sole occupant of the airplane, was fatally injured. The airplane was owned and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Regulations Part 91 personal flight. The local flight was originating at the time of the accident. An FAA inspector, who traveled to the accident site, performed an on-scene examination of the wreckage. The aircraft was reported to have departed the owners grass strip. The private grass strip was approximately 2,000-feet long and was oriented southwest by northeast. The airstrip was located approximately four miles south of Fittstown, Oklahoma, near County Road 1680, approximately one-quarter of a mile from the departure end of the runway. The right wing of the airplane struck a utility wire and impacted a tree. The right wing was sheared from the airplane and the fuselage continued in the direction of the impact for approximately 60 feet. The main wreckage came to rest in an inverted position on a concrete foundation on a heading of 160 degrees. The fuselage of the airplane was consumed by a post-impact fire. The GPS coordinates for the accident site were 34 degrees 34 minutes North and 96 degrees 38 minutes West. There were no reported eye-witnesses to the accident. The 16,500- hour pilot held an airline transport pilot certificate with ratings for single-engine land, multi-engine land, and instrument airplanes. His most recent Federal Aviation Administration first class medical was issued on October 24, 2005. The pilot's logbook was reported to be aboard the airplane and consumed by the post-impact fire. The 1937 model vintage airplane, serial number 364, was powered by a 145-horsepower Warner SS50 radial engine, was certificated for single pilot operation, with seating for four occupants. The total time on the airframe and engine could not be determined. The engine and airframe logbooks were reported to be aboard the airplane, and were consumed by the post-impact fire. Records from the airframe and power plant mechanic who performed the last annual inspection indicate that the last annual inspection was completed on March 21, 2005. The airplane had accumulated a total of 2,001.9 hours at the time of the inspection. The total time on the airplane at the time of the accident is unknown. The wreckage of the airplane was recovered to Air Salvage of Dallas, near Lancaster, Texas, for further examination. On, March 28, 2006, the Warner SS50 engine was inspected by an investigator from the National Transportation Safety Board Investigator and an FAA certified airframe and power plant mechanic at Air Salvage of Dallas, near Lancaster, Texas. Examination of the engine revealed that the number 4 cylinder head was found to have a crack by the exhaust port to the rear spark plug threads, through the thickness of the cylinder. Additionally, the exhaust valve on the same cylinder was also found to have discoloration similar to that of which a stuck valve would have due to "blow torching." The exhaust valve stem was also found to have splattered molten metal attached to it. The exhaust manifold leaving the cylinder also had evidence of molten metal splatter. At 1229 local time, the weather observation facility at Ada Municipal Airport (ADH) near Ada, Oklahoma, located 14 nautical miles from the site of the accident, reported the winds from 160 degrees at 8 knots, visibility 10 statute miles, clear of clouds, temperature 75 degrees Fahrenheit, dew point 28 degrees Fahrenheit, and barometric pressure setting of 30.21 inches of Mercury. The Office of the Medical Examiner of Oklahoma County, located in Oklahoma City, OK, performed an autopsy on the pilot on March 7, 2006. The FAA, Toxicology Accident Research Laboratory, located in Oklahoma City, Oklahoma, conducted toxicological testing on the pilot. The wreckage of the airplane was released to the owner' representative upon completion of the investigation.

Probable Cause and Findings

The loss of engine power due to a cracked cylinder head. A contributing factor was the lack of suitable terrain available to the pilot for the forced landing.

 

Source: NTSB Aviation Accident Database

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