NTSB Factual Report

HISTORY OF FLIGHT

On November 29, 2002, at approximately 1200 central standard time, a Cessna 172N single-engine airplane, N5155E, registered to and operated by Chickasha Aviation Center, Inc., of Chickasha, Oklahoma, was destroyed following an in-flight break up while on a pipeline patrol flight in the vicinity of Lindsay, Oklahoma. The commercial pilot, sole occupant of the airplane, was fatally injured. Visual meteorological conditions prevailed and a flight plan was not filed for the Title 14 Code of Federal Regulations Part 91 aerial observation flight. The local flight originated from the Chickasha Municipal Airport (CHK), near Chickasha, Oklahoma, at 1130.

A witness observed the aircraft fly over the pipeline approximately one half of a mile southeast of his home, a few minutes before noon. The witness added that he did not see the mishap, but at 1200 he reported a fire in the field and discovered the burning aircraft when he went to investigate.

Evidence at the accident site revealed that the right wing separated from the aircraft prior to impact. Further examination revealed that the right wing's strut to fuselage fitting was missing the nut that secures the fitting to the fuselage.

PERSONNEL INFORMATION

The 54-year old pilot was the owner/operator of Chickasha Aviation Centers, Inc., and was under contract to Anadarko Oil Co., to fly pipeline inspections. He held a commercial pilot certificate with single-engine land, multi-engine land, and instrument ratings. He also held a repairman certificate and a mechanic certificate with airframe and powerplant ratings. The pilot's most recent FAA second-class medical certificate was issued on October 23, 2002, with a restriction to wear corrective lenses for near and distant vision. On the application form for his medical certificate, the pilot reported a total flight time of 2,100 hours.

AIRCRAFT INFORMATION

The Cessna 172N, serial number 17271741, was manufactured in October 1978, and was equipped with extended range fuel tanks. An 18-gallon fuel tank was added to the baggage compartment, STC SA615NE, and documented on FAA Form 337 on October 22, 1988.

The aircraft was in a previous accident on October 19, 1996, and sustained substantial damage to the horizontal and bulkhead fitting, right outboard gear box fitting, and structural damage to the right wing strut fuselage attach fitting, upper and lower cowl, right wing, and tail. Major repair of the right wing was accomplished by a FAA certified mechanic and documented in FAA Form 337 on July 16, 1997. The aircraft was registered on July 19, 1997. Over the next 44 months, the remaining damage was repaired, including repairs to the right inboard and outboard landing gear support and several cabin skins. All were documented in FAA Form 337 on April 16, 2001. The aircraft went through an annual inspection and was returned to service on April 24, 2001. The aircraft was registered to Chickasha Aviation Centers Inc., on August 8, 2002.

On June 8, 1983, a "camera hole" was installed on the right side of the aircraft. Cockpit sun visors were installed on June 5, 1987, a standby vacuum system was installed on April 11, 1990, and a 180 rated-horsepower Lycoming O-360-A4M engine was installed on March 16, 1993. All modifications were documented in FAA Form 337.

Documentation of the repair performed on the right wing strut fuselage attach fitting was not found.

According to maintenance records, the last annual inspection was completed on May 3, 2002. The total airframe time was 3,272.6 hours. The exact total airframe time as of the accident date could not be retrieved due to post-impact fire damage to the Hobbs meter and tachometer.

METEOROLOGICAL INFORMATION

At 1150, the weather facility at CHK located 23 nautical miles southwest of the accident site reported the winds from 220 degrees at 10 knots, visibility 10 statute miles, temperature 13 degrees Celsius, dew point 7 degrees Celsius, and an altimeter setting of 30.03 inches of Mercury.

WRECKAGE AND IMPACT INFORMATION

The aircraft impacted terrain after the right wing separated from the fuselage in-flight. The left wing tip created a ground scar about 20 feet long before the fuselage first impacted the ground. The global positioning system (GPS) coordinates were 34 degrees, 48 minutes North, and 097 degrees, 39 minutes West, at an elevation of 1,105 feet. The fuselage came to rest right side up with a roll attitude of approximately 30 degrees to the left on a heading of 100 degrees. The right wing and strut were found 360 feet northwest of the fuselage and the right wing tip was found 909 feet northwest of the fuselage. The left landing gear leg and wheel assembly were found 25 feet to the right of the fuselage, and the right door was found 50 feet to the right of the fuselage.

A post-impact fire, fed by fuel in an 18-gallon auxiliary fuel tank installed in the baggage compartment and fuel in the long-range fuel tank in the left wing, consumed most of the fuselage except for the empennage and most of the left wing.

The right wing exhibited no damage prior to the separation in-flight. The right strut to fuselage fitting attach bolt was observed to be wedged in the lower strut attach fitting at about 15 degrees, with the threads of the bolt engaged in the forward hole of the fitting. The aft hole of the fitting and the threads of the bolt appeared to be undamaged. The nut for the attach bolt was not found in the wreckage. Control cable continuity was established in the right wing from the wing root to the aileron and to the flap. Tension overload signatures were found on each cable. Due to the post-impact fire, control cable continuity in other areas could not be verified.

The right wing fuel tank was ruptured and showed signs of hydraulic deformation. There was approximately one half of a gallon of blue-colored fuel remaining in the right fuel tank and the fuel filler cap was in place and correctly installed. The fuel lines were separated at the wing root. Due to the post-impact fire, evaluation of the left wing fuel tank and fuselage could not be assessed.

The seat rails were melted and the condition of the seat frames could not be determined prior to the post-impact fire. Safety restraint use and the condition of the restraint devices also could not be determined. The outboard seat belt attach fittings for both front seats were observed and attached to the fuselage.

The engine was attached to the engine mounts. The propeller was attached to the propeller flange, and was bent aft at mid span and exhibited torsional bending. The tips of the propeller showed chordwise striations. The ring gear was broken free of its plate. Evaluation of the accessories, position of the engine fuel controls, and fuel and oil lines could not be assessed.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy on the pilot was performed by the Office of the Medical Examiner, Oklahoma City, Oklahoma. No evidence of any preexisting disease that would have contributed to the accident was found.

Toxicological testing was performed by the FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma. Toxicology tests found various drugs in the pilot. These drugs were found to be those that treat colds, including antihistamines, cough suppressants, and pain relievers. The results of the toxicology tests for alcohol were negative.

ADDITIONAL INFORMATION

The wreckage was released to the owner's representative on December 17, 2003.

NTSB Probable Cause

The in-flight separation of the right wing due to the missing nut that secures the right wing's strut to fuselage fitting to the fuselage.