OSHKOSH, WI, USA
N3025
GRUMMAN G58A
DURING INITIAL CLIMB THE ENGINE BACKFIRED AND SUSTAINED A POWER LOSS. THE PILOT CONFIGURED THE AIRPLANE FOR A FORCED LANDING WITH THE LANDING GEAR AND FLAPS EXTENDED. ON TOUCHDOWN THE AIRPLANE CARTWHEELED. A POST ACCIDENT EXAMINATION REVEALED THAT THE MIXTURE CONTROL WAS PARTIALLY CLOSED. NO OTHER ANOMALIES WITH THE AIRPLANE WERE FOUND ON FURTHER EXAMINATION.
HISTORY OF FLIGHT On August 1, 1993, at 1418 central daylight time, a Grumman G-58A, N3025, registered to and operated by Elmer F. Ward, a private pilot of Santa Ana, California, experienced a loss of power on takeoff from runway 18 (8,001' x 150' dry/concrete) at the Wittman Regional Airport, Oshkosh, Wisconsin. A forced landing was made in an open field one-half mile south of the airport. On touchdown the airplane impacted the terrain and sustained substantial damage. The pilot received serious injuries. The personal flight was being conducted under the provisions of 14 CFR Part 91, in visual meteorological conditions. The flight was being conducted in conjunction with the annual Experimental Aircraft Association's convention. No flight plan was on file. The local flight was originating at the time of the accident. The pilot stated that shortly after takeoff (altitude of 75 to 100 feet above ground level) the engine lost power and did not respond to control inputs. He stated that he could not account for the midrange location of the mixture control as found at the accident site. He stated that he left the gear extended and lowered the flaps to full down. He indicated that the airplane impacted the ground in a full stall condition, right wing low, and cartwheeled clockwise on the nose and left wing. There were no actual witnesses other than the pilot to the impact, although several witnesses saw the aircraft descending. Their view of the impact was out of their line of sight due a depression in the terrain to the south of the airport, where the accident occurred. One witness near the runway when the airplane departed, stated that the engine sounded as if it was running strong; however, about the time it passed in front of him from north to south, it backfired one time and the engine sound diminished. He watched the airplane descend out of sight, to the south, just prior to impact. He did not hear the engine noise increase during that time, although he believed that it did continue to run at a lower power setting until impact. PERSONAL INFORMATION The pilot born May 6, 1921, held a private pilot certificate with an instrument rating for airplanes. He had accumulated 2,256 hours total time at the time of the accident with 56 hours in this make and model of airplane. He was the holder of a third class medical certificate issued April 3, 1992, with the vision restriction for wearing lenses for near vision. His last biennial flight review was on March 26, 1992. AIRCRAFT INFORMATION The airplane was a Grumman G58A, N3025, serial number 739A. Total airframe time is unknown. The airplane and engine had accumulated 78 hours time in service since overhaul. The last annual inspection was performed on July 14, 1993. WRECKAGE AND IMPACT INFORMATION The airplane impacted the terrain approximately one-half mile off the departure end of runway 18 at Wittman Regional Airport at Oshkosh, Wisconsin. The impact occurred an open field of tall grass, which slopped slightly downhill to the south, in the direction of travel. The airplane was configured as the pilot indicated with the landing gear and flaps in the extended position. During the impact the landing gear collapsed and was torn from the airframe. The pilot stated that the airplane cartwheeled clockwise on the main landing gear and the right wing, followed by the engine and left wing. Ground scars confirm that the impact was as described by the pilot. Wing and landing gear parts were found along the debris trail and within the ground scars left by the impact. The airplane was examined at the accident site minutes after the accident. At the arrival of inspectors, the pilot was trapped inside the airplane, and rescuers had difficulty in opening the canopy to remove the pilot. During this time the pilot was unconscious and not moving. Immediately after the pilot was freed from the airplane, an examination of the cockpit was conducted. Switches and controls were in the "as found" condition. The throttle was full forward. The mixture and propeller controls were approximately midrange. The mixture control was near the idle cutoff position. The airplane was removed from the accident site and returned to the airport for a thorough examination. Flight and engine control continuity was confirmed. The engine controls had full travel. An examination of the engine failed to reveal any anomalies when examined. Fuel was found in the carburetor, lines and tank. Filters were clean. Engine rotation was checked and valve and accessory rotation was observed. Several spark plugs were removed and found to have combustion deposits on the electrodes. Oil was examined and found to be free of foreign material and the oil filter was clean. ADDITIONAL INFORMATION Party to the investigation was the Federal Aviation Administration, Flight Standards District Office, Milwaukee, Wisconsin. The NTSB did not retain possession of the wreckage beyond the examination, which took place immediately after the accident. The airplane's location was known to the pilot's family at the time the NTSB departed the accident scene and they assumed responsibility for it.
THE PILOT-IN-COMMAND'S INADVERTENT USE OF THE MIXTURE RESULTING IN A LEAN MIXTURE.
Source: NTSB Aviation Accident Database
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