Stockbridge, GA, USA
N7948F
CESSNA 150
The private pilot completed an engine run-up before the personal flight with no anomalies noted. The pilot rotated the airplane about halfway down the runway. He stated that the airplane was not climbing normally during the takeoff, and a ground witness heard the engine making "popping" noises. The pilot attempted to clear trees off the end of the runway in order to make a controlled landing in the field on the other side, but the airplane impacted the field; the pilot was unable to recall any events that happened after passing over a tree. Examination of the wreckage revealed that the airplane displayed impact damage that included aftward crushing of the airplane's nose and the leading edges of both wings, which was consistent with an aerodynamic stall and impact with the ground in a nose-low attitude. Examination of the engine revealed the No. 4 cylinder's exhaust valve was stuck in the fully open position and coated in a carbon-like material. The stuck valve likely reduced engine power and airplane performance during the takeoff, which resulted in an aerodynamic stall.
On October 16, 2016, about 1430 eastern daylight time, a Cessna 150 airplane, N7948F was substantially damaged when it impacted a field on takeoff from Berry Hill Airport (7GA7), Stockbridge, Georgia. The private pilot and the passenger sustained serious injuries. The airplane was privately owned and operated under the provisions of a Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed for the flight that was destined for Cherokee County Airport (CNI), Canton, Georgia. The pilot said he added 10 gallons of aviation fuel to each wing tank which brought each tank up to about 3/4 full. He then taxied to his backyard at the fly-in community to pick up his passenger, a bag of clothes, and a small dog. The pilot then taxied to runway 11 and conducted a runup of the engine. The runup was normal and the pilot departed in calm wind. About halfway down the 3,000-foot-long runway, the pilot rotated, and the airplane began to climb. The pilot soon observed that the airplane was not climbing normally, and he grew concerned that he would not clear the tree line about 500 ft off the departure end of the runway. The pilot steered the airplane toward the shortest tree and hoped to make a controlled landing in the field on the other side. He said that he remembered going over the tree, but nothing after that until he woke up in the hospital. A witness observed the airplane during takeoff and heard the engine making "popping" sounds as it climbed out. The pilot said he was wearing noise-cancelling headsets and did not hear anything abnormal with the engine during the quick flight. Post accident examination of the wreckage revealed that it came to rest about 800 ft off the departure end of the runway. The wreckage displayed aftward crushing of the airplane's nose, uniform aftward crush damage along most of the left wing's leading edge, and aftward crush damage to the outboard portion of the right wing. Examination of the engine revealed that each of the four cylinders exhibited dark deposits on the pistons and cylinder domes. When the engine was manually rotated, valve train continuity and compression were established on each cylinder except the No. 4 cylinder. The No. 4 cylinder was removed, and the exhaust valve was found stuck in the fully open position. The valve was manually removed from the cylinder with a hammer and a drift. The valve stem was dark and coated with a carbon-type material. The spark plugs were removed and examined. They exhibited normal wear when compared to the Champion Check-A-Plug chart, and dark deposits were observed in the electrode areas. The No. 4 bottom spark plug had oil and carbon type deposits in the electrode area.Both magnetos were removed from the engine and tested. When manually rotated, spark was produced at each terminal.The carburetor had separated from the engine and exhibited impact damage. The throttle control actuating arm and the mixture control were connected and moved freely. The carburetor heat control was in the center position and would not move. There was no fuel screen installed. The floats were intact and attached to the needle valve. The needle valve seat was absent of debris.The oil screen was removed and a small about of carbon deposits were observed. A review of the airplane's maintenance logbooks revealed the last annual inspection was completed on May 10, 2016. At that time, the engine had accumulated 3,673.55 hours total time, with 604.85 hours since major overhaul. The pilot held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. His last FAA third-class medical was issued on January 14, 2016. The pilot reported 276 total hours with 5 hours total time in the accident airplane make & model. The weather at Henry County Airport (HMP), Hampton, Georgia, about twelve miles southwest of the accident site, at 1435 was wind from 130° at 5 knots, visibility 10 miles, overcast at 9,000 ft, temperature 26° C, dewpoint 18° C, and an altimeter setting of 30.17 inches of mercury. The calculated density altitude was about as 2,100 ft.
A partial loss of engine power due to a stuck exhaust valve and the pilot's exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall.
Source: NTSB Aviation Accident Database
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