NTSB Factual Report

On March 14, 2001, at 0800 central standard time, a Cessna 152 airplane, N757GP, was destroyed when it impacted trees and terrain during a forced landing following a loss of engine power during the initial takeoff climb from the Downtown Airpark Airport, Oklahoma City, Oklahoma. The private pilot, who was the registered owner and operator of the airplane, and his passenger sustained minor injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The local flight was originating at the time of the accident.

According to the pilot, he performed a preflight inspection and taxied to the engine run-up area for runway 16. There were no anomalies noted during the pre-takeoff engine run-up and the pilot performed a normal takeoff. The airplane was climbing through 200 feet agl when the tachometer needle dropped to 2,000 rpm. The pilot performed the emergency checklist for an engine failure immediately after takeoff. He reported that he checked that the primer was in-and-locked, the fuel selector valve was in the on position, the mixture was in the full rich position, and the carburetor heat was off. He added that while he was performing the checklist items, "the engine rpm dropped again the engine appeared to be running rough." A forced landing was initiated and the airplane impacted electrical wires, trees, and terrain south of the airport. The airplane came to rest inverted in the parking area of shopping mall. There was no damage to the mall structure or to any person on the ground.

Review of photographs taken at the accident site revealed that the engine and propeller remained intact. The propeller's spinner assembly was not damaged and it did not exhibit any scratching or rotational damage. A fire consumed the cockpit, cabin, empennage, and sections of each wing. The horizontal stabilizer and vertical stabilizer remained intact; however, they displayed impact damage. Fire damage precluded examination of the airframe fuel system.

According to the maintenance logbooks, between October 1, 1993, and the time of the accident, the airplane flew a total of 4.1 hours. On March 10, 2001, the airplane received its most recent annual inspection. At the time of this annual inspection the airframe and engine had accumulated a total of 2,084.9 hours.

The Lycoming O-235-L2C engine (serial number L1293415) was examined by the NTSB Investigator-In-Charge (IIC), an FAA inspector, and a representative from Textron Lycoming. The air intake system was observed intact. The oil dipstick was removed and indicated that the engine oil level was 5 quarts. Each of the cylinders was examined with a boroscope, all appeared intact and no corrosion was observed. The crankshaft was manually turned and continuity was confirmed between the propeller flange and the accessory drive gears. Thumb compression and suction were obtained on all 4 cylinders. Ignition timing was verified at 20 degrees before top dead center. The magnetos were removed, and when manually turned, each of the leads produced a spark. The oil filter was examined and found free of contaminants. The gasculator bowl was removed and observed dry and corroded; however, its screen was clear. The carburetor was removed and displayed thermal damage. The mixture control at the carburetor was found in the full rich position and the throttle was found in the 3/4 open position. The carburetor's fuel screen was removed and observed to be clear, and free of debris.

The carburetor was examined at J & G Aero Carburetor Inc., of Dallas, Texas. There were no signatures indicative of internal thermal damage. The idle mixture was set within the manufacturer's specifications. The composite floats were intact and the bowl was clean, free of debris, and no corrosion was present. The two-piece venturi and the throttle control shaft were in place and intact. There were no anomalies noted that would prevent operation of the carburetor.

At 0755, the weather observation facility at Tinker Air Force Base, Oklahoma City, Oklahoma, (approximately 5 miles from the accident site) reported a scattered cloud layer at 700 feet, a broken cloud layer at 12,000 feet, visibility 7 miles, temperature 55 degrees Fahrenheit, dew point 48 degrees Fahrenheit, wind from 170 degrees at 13 knots with gusts to 20 knots, and an altimeter setting of 29.71 inches of Mercury.

The temperature and dew point were plotted on an icing probability curve by the NTSB IIC. The plot revealed that the conditions were conducive to serious icing at cruise power.

NTSB Probable Cause

the loss of engine power during the initial takeoff climb for an undetermined reason, which resulted in a forced landing. A contributory factor to the accident was the lack of suitable terrain for the forced landing.