NTSB Factual Report

HISTORY OF FLIGHT

On July 17, 1994, at 1115 Pacific daylight time, a Cessna 172M, N1259U, crashed and burned while on a climb out from Natomas airport, Sacramento, California. The aircraft was owned and operated by American Aero Club, Inc., and was on a personal flight. Visual meteorological conditions were prevalent at the time and no flight plan had been filed for the local operation. The certificated private pilot and his three passengers were fatally injured. The flight was originating at the time of the accident.

The accident aircraft was scheduled to be flown on July 15 and had been subsequently rejected by another pilot due to what he described as an insufficient static power check. (The manufacturer states the maximum static rpm should be 2,350 rpm and the minimum should be 2,270 rpm.) That pilot stated that he reported the deficiency to a club mechanic. Since the aircraft was approaching a 50-hour inspection, the mechanic decided to go ahead and perform the inspection. Accordingly, the 50-hour inspection was performed and the aircraft was put back on the line.

The next day, on July 16, a second pilot rejected the aircraft for, what was again described as, an insufficient static power check. He reportedly was only able to develop between 1,900 and 2,000 rpms. The pilot stated that he described the deficiency to a club mechanic. The mechanic told investigators that to correct the problem he performed a run-up to clean the spark plugs and afterwards found no power deficiency. When interviewed by investigators, he was uncertain what the actual static rpm should be. He attributed the source of the problem to running the aircraft on the ground with a "rich idle" for too long, which had caused the spark plugs to foul, producing a power loss. After completing a power check, the mechanic again returned the aircraft to the line.

After being placed back on the line on July 16, the aircraft was flown twice during the remainder of the day. Both pilots found the aircraft performance to be normal.

On July 17, the pilot arrived at the airport and initially waited for his passengers to arrive. During his wait, he talked to another club member, who reported nothing unusual about the pilot or conversation. Witnesses stated that they then saw the pilot preflight the aircraft, enplane his passengers, and taxi from the flight line toward the active runway.

Witnesses who observed the aircraft's departure from runway 16 at Natomas airport described, what they concluded to be, several attempts to rotate the nose before the aircraft had obtained sufficient flying speed. One witness, who stated that he saw the aircraft early in the takeoff phase, reported that the aircraft was rolling down the runway on the main gear, but with the aircraft nose wheel off the runway. The pilot was then observed to lower the nose to the runway. A few seconds later, he was again observed attempting to rotate the aircraft. This time the aircraft climbed approximately 2 feet above the runway before settling back onto the runway. After both attempts, the pilot continued in his takeoff roll.

On his third attempt, with approximately 20 to 25 percent of the runway remaining, the pilot was successful in initiating a climb and remaining airborne. Witnesses described the aircraft's initial climb performance as "wallowing," with a slow rate of climb and an unusually steep nose attitude. A Federal Aviation Administration (FAA) inspector who observed the aircraft from his car concluded from what he observed that an instructor was probably demonstrating a short field takeoff.

After takeoff, the aircraft was described as climbing to approximately 300 feet agl while making a shallow, left 90- degree, crosswind turn. During that time, the pitch attitude of the aircraft was observed to increase and decrease in what, according to the opinion of witnesses, was an attempt to increase airspeed. Witnesses then described a second shallow, left 90-degree downwind turn. Again, the pitch attitude of the aircraft was observed to increase to an estimated 30 degrees, then decrease. However, as the pitch attitude of the aircraft decreased for the final time, the left wing dropped and the aircraft suddenly descended toward the ground in a 70-degrees nose-low attitude. One witness near the impact site reported what he heard as a "popping" sound coming from the engine just prior to the crash.

PERSONNEL INFORMATION

The pilot's logbook and the flying club's records were reviewed by investigators. There were no records reflecting a current biennial flight review (BFR).

There were no records reflecting that the pilot had flown any aircraft within the preceding 90 days. The last record for a flight in the same make and model was on October 17, 1993. The last record for a flight in any aircraft took place on March 13, 1994, in a Cessna 150.

AIRCRAFT INFORMATION

A review of the engine logbook revealed total engine time was 2,155.7 hours since major overhaul. The manufacturer recommends a major overhaul after 2,000 hours service.

A weight and balance computation was provided by the manufacturer's representative. Based on the occupant weights and their position in the aircraft provided by the Coroner, full fuel and the manufacturer's empty weight of the aircraft, the aircraft was at its maximum allowable gross weight and was near its aft center of gravity limit.

During the postcrash inspection of the engine, it was noted that the number 2 exhaust rocker arm was an incorrect part. The part installed was identified as an intake rocker arm.

According to club records, the aircraft was being operated with auto-gas under Patterson STC SA1948CE. It had been reportedly topped off with auto-gas mixed with 10 percent 100 low-lead aviation fuel before departure. The fuel capacity of both tanks totaled 42 gallons.

WRECKAGE AND IMPACT INFORMATION

The aircraft impacted on level, dry, grassy terrain, about 1/2- mile south of the airport creating a ground scar approximately 6 feet in length, 3 feet in width, with an average depth of 4 inches. The final heading of the aircraft after impact was 195 degrees. The dry grass in an approximate 40-foot radius around the initial impact point was burned and blackened.

Control continuity was established for the ailerons, elevators, and rudder. The flap actuator was found extended 5.75 inches and, according to the manufacturer's charts, corresponds to a flap position of 37 to 38 degrees. The elevator trim actuator was found extended 1.5 inches and, according to the charts, corresponds to a 10-degrees tab up position.

The crush on the leading edges of the main wings was both rearward and upward at an approximate 45- to 50-degree angle. The leading edge crush was evident on the outboard portion of the left wing. Both wings showed evidence of scorching and fire involvement toward the wing roots.

The fuselage from the propeller aft to the vertical stabilizer had been consumed by fire. The empennage showed evidence of scorching, particularly on the left side.

The nose wheel was displaced and collapsed aft. Both main gear were separated from the aircraft. All three had evidence of fire damage.

Both main fuel tanks were ruptured and exhibited evidence of hydraulic deformation. There was no residual fuel in the right tank. In the left tank, there was approximately 1 quart of fuel with water contamination. Both tanks exhibited evidence of fire damage. The main fuel valve was not located in the debris. The gascolator was missing from its installed position and was not located in the wreckage debris.

The carburetor was removed from the engine and visually examined. It was equipped with a metal float and a single-piece venturi. No fuel was present in the carburetor bowl. The fuel inlet screen was clean and free of contaminants.

The ignition system exhibited evidence of exposure to fire and heat. Both magnetos were destroyed in the postcrash fire. Both magneto drive gears were found intact. The left magneto was equipped with an impulse coupler. The coupler was intact and functioned during a manual rotation.

The vacuum system had fire damage. The vacuum pump was found separated from the engine. The drive coupler was melted. The vanes were found intact, but the rotor was fractured.

The oil suction screen was removed and visually examined. It was found free of contamination. The oil filter and adapter had separated from the normal location on the engine and were not located in the wreckage debris.

A partial rotation of the engine crankshaft was performed. Gear and valve train continuity were established during the rotation.

The propeller was partially separated from the flange, being retained by a single bolt. The first blade exhibited evidence of having been partially melted and consumed by fire. The second blade had a torsional twist. The tip of the second blade also showed evidence of having been partially melted and consumed by fire. The spinner exhibited longitudinal crushing and rotational scarring.

The metal buckles of the seatbelts and front seat shoulder harnesses were located in the wreckage. The seatbelts and shoulder harness were burned away, however, the buckles were found in the latched position.

MEDICAL AND PATHOLOGICAL INFORMATION

The Sacramento County Coroner's office performed an autopsy on the pilot. Samples were retained for toxicological analysis. The results of the toxicological tests were negative for all screened drug substances and alcohol.

FIRE

The aircraft was partially consumed by a postcrash fire. Both main fuel tanks were ruptured and burned. Each tank exhibited hydraulic deformation. The fire was primarily centered in the wing roots and the mid-to-forward fuselage area.

ADDITIONAL INFORMATION

The aircraft wreckage was released to Dennis James of Plain Parts, Pleasant Grove, California.

NTSB Probable Cause

the failure of the pilot to maintain adequate airspeed while maneuvering after takeoff and his failure to retract the flaps prior to departure. A factor in this accident was the pilot's lack of recent experience.