NTSB Factual Report

HISTORY OF FLIGHT

On January 12, 1997, at 1340 eastern standard time, a Cessna 150L, N10809, was destroyed when it struck the ground after departure from the Perkiomen Valley Airport, Collegeville, Pennsylvania. The certificated commercial rated flight instructor and pre-solo dual student were fatally injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the local dual instructional flight. The flight was estimated to have departed about 1200, and was conducted under 14 CFR Part 91.

There were no known witnesses to the pre-flight activities or the initial departure of the flight; however the airplane was observed in the traffic pattern performing takeoffs and full stop landings.

A pilot who entered the traffic pattern behind N10809, reported that after N10809 landed, it cleared the runway and taxied back for another takeoff. The pilot landed behind N10809, and cleared the runway at mid-field. While taxiing on the parallel taxiway, the pilot observed N10809 depart on runway 27. The pilot recognized the instructor in the right seat and waved to him. The pilot crossed runway 27 near the departure end of the runway and taxied to her parking spot, and as she swung her airplane to the south, she observed N10809 in a bank of 70 to 80 degrees, left wing down, and 20 degrees nose down, while moving left. The airplane was about 150 feet above the ground. She watched it until it disappeared from view.

Another witness who observed the takeoff reported the wings were rocking from side to side after liftoff, and the engine was sputtering. He did not recall the engine surging to high power and a few seconds later when he saw the airplane it was about 200 feet high, descending in a nose down attitude.

Another witness about 1 mile south of the airport reported seeing a white airplane with red trim climbing in a nose high attitude. The airplane then rolled left and descended until it disappeared from view. The witness reported that the engine sounded labored.

One witness in reported hearing the engine shut off or fade away, followed a few seconds later by the sound of branches braking and then a thud.

The airplane struck trees and came to rest on its left side in the driveway of a residence.

The accident occurred during the hours of daylight about 40 degrees, 12 minutes North latitude, and 75 degrees, 26 minutes West Longitude.

PERSONNEL INFORMATION

The flight instructor held a commercial pilot certificate with ratings for airplane single engine and multi-engine land and instrument airplane. In addition, he held a flight instructor certificate for airplane single engine land and instrument airplane. He was issued a second Class FAA Airman Medical certificate on March 18, 1996, with limitations. The flight instructor's pilot log book was not recovered. According to his FAA Airman Medical application, he listed his total time as 6,420 hours.

There was no record that the student pilot possessed a student pilot certificate. According to his training syllabus, he had not soloed. The training syllabus recorded dates flown, but did not include flight times. According to the syllabus, the student pilot had received 49 dual instructional flights, with 9 flights in the preceding 90 days. The student pilot was estimated to have about 50 hours total flight experience, all dual instruction.

METEOROLOGICAL INFORMATION

A pilot that landed after N10809 reported the winds were from the northwest, 310 degrees at 15 knots, with gusts to 22 knots.

WRECKAGE AND IMPACT INFORMATION

The airplane was examined at the accident site on January 12 and 13, 1997. The airplane was on its left side and the wings were rotated about 60 degrees left wing aft and 60 degrees right wing forward. The empennage had been separated from the fuselage to facilitate the removal of the occupants, and was laying on the ground nearby.

The leading edge of both wings contained impact damage with more crushing visible on the outboard 6 feet of the left wing. The outboard 4 1/2 feet of the right wing was observed at the base of a tree along with numerous broken branches of various sizes.

The fuel caps were in place and both fuel tanks contained fuel. Fuel samples from the carburetor, fuel strainer, and fuel tanks were bright and clear. No water was observed in the fuel tanks, or carburetor. About 1/2 ounce of frozen water was observed in the bottom of the fuel strainer. The fuel filters in the carburetor and fuel strainer were absent of debris. The fuel lines between the fuel tanks, and the carburetor were free of obstructions.

Both control yokes had been cut and removed to facilitate the removal of the occupants. The seatbelts had been cut on the outboard side of each seat and the were still latched. The latches operated in a free and easy manner with no binding. The inboard seat belts, between the seats, were frayed and stretched. The shoulder harnesses were not attached to the seatbelts. The shoulder harness belts under the lock rollers did not have a shine, nor were the belts deformed in that area. The seats remained attached to their seat rails, and the back of the right seat was broken on its outboard brace.

The cockpit throttle and mixture controls were broken off; however, on the carburetor, the throttle setting was in the full open position, and the mixture setting was in the full rich position. The carburetor heat box was in the carburetor heat off position, with the control arm bent. No obstructions were observed in the air filter or duct. The carburetor venturi was in place. The carburetor bowl contained fuel, the carburetor floats were constructed of metal, and free of fluid. When stroked, the accelerator pump squirted fuel into the carburetor venturi.

The top spark plugs were light gray in appearance with no evidence of impact damage. Using a finger to restrict air flow in the cylinder, the engine was rotated, and compression observed in cylinders, one, two, and three. The number four cylinder (left front) had a cracked head. Spark was obtained from the four upper sparkplug magneto leads of both magnetos.

On blade of the propeller was bent rearward about 30 degrees at the mid-span position. There were small impact marks on the leading edge of the bent blade and none on the other blade.

Flight control continuity was confirmed between the ailerons and control yokes. Flight control continuity was also confirmed between the empennage and the cut control cables, and between the crushed area near the rudder pedals and the control cable cuts.

The left horizontal stabilizer was separated from the empennage. A semicircular indentation was observed on the leading edge of the left horizontal stabilizer with its centroid 14 inches outboard of the fuselage, and at a depth of 6 1/2 inches. In addition, the left elevator was separated from the left horizontal stabilizer.

MEDICAL AND PATHOLOGICAL INFORMATION

Autopsies were conducted on both pilots on January 13, 1997, by Sara Lee Funke, M.D., a private practice Forensic Pathologist for Montgomery County, Pennsylvania.

Toxicological testing was conducted by the FAA Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma. The results were negative for drugs and alcohol.

ADDITIONAL DATA/INFORMATION

A pilot who had flown out of the airport for 7 years reported that she had observed the flight instructor numerous times. She noticed that the flight instructor had a tendency to make the initial climb with a steeper nose high attitude than other pilots operating Cessna 150s from that airport.

A flight instructor from the airport also reported that he had observed the flight instructor climbing at what he thought was too steep an attitude several times.

The aircraft was released to Mr. John Cooley, an insurance adjuster on January 13, 1997.

NTSB Probable Cause

The loss of engine power for undetermined reasons, and the pilot's failure to maintain adequate airspeed during the forced landing, which resulted in a stall and collision with the ground. A contributing factor was wind gusts.