NTSB Factual Report

HISTORY OF FLIGHT

On September 14, 1998, at 0820 mountain daylight time, a Cessna 172N, N737NH, was destroyed during impact with terrain near Montezuma Creek, Utah. The commercial pilot, the sole occupant on board, was fatally injured. The airplane was owned/operated by Four Corners Aviation Inc., Farmington, New Mexico, under Title 14 CFR part 91. Visual meteorological conditions prevailed for the cross-country pipeline inspection flight which originated from Farmington, New Mexico, approximately 1.5 hours before the accident. A company VFR flight plan was on file with the FAA.

According to the pilot's employee records, he started flying pipeline inspection flights in September, 1997. According to the senior pilot on the pipeline project, the pilot received a ground briefing and flight checkout which included: recommend inspection altitudes (100 to 150 feet agl), recommend airspeeds (not less than 80 knots), and bank angles not to exceed 45 degrees.

On the morning of the accident, company records indicate that the airplane was topped-off with 33 gallons of fuel. A witness reported that the pilot departed Farmington at approximately 0650 for a pipeline inspection flight to California.

Another witness observed the airplane flying on a heading of approximately 250 degrees and then "it started climbing to near vertical with a little left turn. He went over the top and turned left spinning left 2 times." Another witness stated that she had seen the airplane many times, and she observed it frequently fly side-to-side (90 degree knife edges) or do "pop-up turns." She further thought to herself that "someday he would crash or get in trouble." On the day of the accident, she saw the airplane coming from the east at what she thought was 250 to 300 feet agl, when "he popped up, but this time he started to go right on over (on his back). He [then] fell straight down hitting the ground, and I heard him crash." She reported that she was outdoors and heard the engine "clearly running to impact."

PERSONNEL INFORMATION

According to the pilot's flight logbook, he received his private pilot's certificate on August 31, 1991. FAA records indicate that he had progressively received his commercial certificate and instrument rating, and that he received his single engine flight instructors certificate on July 28, 1998. This oral examination and flight check ride would meet the requirements for the required FAA Part 61 flight review. His flight logbook, along with company employee records, indicate that he had approximately 1,500 hours of flight experience at the time of the accident.

AIRCRAFT INFORMATION

The airplane was a propeller-driven, four seat airplane, which was manufactured by the Cessna Aircraft Company in 1977. It was certificated for a maximum gross takeoff weight of 2,300 pounds. The airplane was powered by a Textron Lycoming O-320, four cylinder, reciprocating, horizontally opposed, carbureted engine which had a maximum takeoff rating of 150 horsepower. At the time of the accident, aircraft records and engine tachometer readings indicate the airframe had accumulated approximately 3,984 hours of flight.

The airplane had an Airworthiness Certificate for normal flight operations; under this certificate designation, acrobatic flight is prohibited.

METEOROLOGICAL INFORMATION

At 0853, the weather conditions at the Cortez Municipal Airport (elevation 5,914 feet), 080 degrees 32 nautical miles from the accident site, were as follows: wind calm; visibility 10 statute miles; cloud condition clear; temperature 57 degrees Fahrenheit; dew point 46 degrees Fahrenheit; altimeter 30.13 inches of mercury. The density altitude at the accident site was calculated to be 5,246 feet.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted sagebrush covered rolling desert terrain (elevation 4,850 feet) approximately 3/4 nm south [160 to 170 degrees] of the Texaco gas station in Montezuma Creek, New Mexico, (N37 degrees 14.841 minutes, W109 degrees 18.264 minutes). The airplane was found in near vertical orientation (aligned 010 degrees) with wings level to the horizon; the empennage was bent just behind the wings which allowed the empennage to come to rest approximately 40 degrees aft of vertical. The propeller was found buried in the soil and the engine was displaced aft into the cockpit area. The leading edges of both wings were crushed straight back (see photographs) and both main fuel tanks demonstrated evidence of being compromised by hydraulic ruptures.

All flight control surfaces were accounted for; control cable continuity was established from each control surface except the left aileron (impact damage); and the flaps were found in the up position. The engine's crankshaft was rotated by hand to confirm engine continuity, and cylinder "thumb" compression checks on all 4 cylinders did not identify any anomalies. Valve continuity was visually confirmed and all accessory gears rotated. The single-drive dual magneto remained attached to the accessory housing, but was destroyed by impact forces. The engine's carburetor was destroyed except for the metal carburetor floats which exhibited hydraulic deformation. The throttle and mixture engine control levers were both found full forward; the carburetor heat was full in.

The airplane's instrument panel was destroyed with the following exceptions: the engine RPM gauge read 2,500; and the airspeed indicator read 63 knots. The fuel selector was found on both. When the engine was extricated from the ground, both propeller blades were still attached with the following damage: both propeller blades were bent aft, and they demonstrated chordwise striations and polishing. One blade revealed an "S" type of bend. The spinner was crushed aft in a rotational manor opposite the direction of rotation.

All major components of the airplane were accounted for at the accident scene. There was no evidence of pre or postimpact fire. No preimpact engine or airframe anomalies, which might have affected the airplane's performance, were identified.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy on the pilot was performed by Dr. Edward A. Leis, a forensic pathologist, at the State of Utah, Department of Health, Salt Lake City, Utah, on September 15, 1998.

The State of Utah, Department of Health, Utah Office of the Medical Examiner, did perform toxicology tests (case #199801150) on the pilot. The results were negative.

TEST AND RESEARCH

FAA FAR 91.303 defines aerobatic maneuvers as "intentional maneuvers involving an abrupt change in an aircraft's altitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight." The regulation also prohibits aerobatic flight over any congested area of a city, town, or settlement and within 4 nautical miles of the center line of any Federal airway.

FAA FAR 91.307 defines the flight parameters for when a pilot must wear a parachute: Unless each occupant of the aircraft is wearing an approved parachute, no pilot of a civil aircraft may execute any intentional maneuver that exceeds- 1. A bank of 60 degrees relative to the horizon; or 2. A nose-up or nose-down attitude of 30 degrees relative to the horizon.

ADDITIONAL DATA

The airplane, including all components and logbooks, was released to a representative of the owner's insurance company on July 1, 1999.

NTSB Probable Cause

The pilot's attempted aerobatic maneuver and the subsequent inadvertent stall/spin. A factor was his intentional low altitude flight.