BELEN, NM, USA
N4069Z
Piper PA-18-150
The pilot received his private pilot's license earlier that morning and was taking his brother for a ride. He said that shortly after he lifted off from an abandoned 800-foot airstrip (elevation unknown, but an airport 7 miles southeast of the accident site is at 5,194 feet msl) but using a short-field takeoff technique (full flaps), the engine began to lose power, dropping about 500 to 700 rpm (revolutions per minute). When he leveled off to maintain airspeed, the engine 'shut down completely.' Because flaps were still extended and airspeed in the flare was low, the airplane 'kept coming down.' A hard landing ensued, shearing off the landing gear and bending the engine mounts and propeller. The mixture control was found in the FULL RICH position. There was a tail wheel strike mark in the dirt 168 feet from the runway threshold. Just beyond were two dirt berms that had been struck by the airplane's main landing gear. The engine was partially disassembled. The no. 2 cylinder compression ratio was 45/80, due to exhaust blow-by.
On March 12, 2000, approximately 1630 mountain standard time, a Piper PA-18-150, N4069Z, operated by S&P Aviation, LLC., was substantially damaged when it collided with terrain during a forced landing 7 miles northwest of Belen, New Mexico. The newly certificated private pilot and his passenger were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The flight was originating at the time of the accident. The pilot told an FAA inspector that he had received his private pilot's license earlier that morning, and he was taking his brother for a ride. In his accident report, he said that shortly after he lifted off from an abandoned 800-foot long airstrip using a short-field takeoff technique (full flaps), the engine began losing power, dropping about 500 to 700 rpm (revolutions per minute). When he leveled off to maintain airspeed, the engine "shut down completely." Because flaps were still extended and airspeed in the flare was low, the airplane "kept coming down." A hard landing ensued, shearing off the landing gear and bending the engine mounts and propeller. The FAA inspector examined the airplane at the accident site. He found the mixture control in the FULL RICH position [the elevation of the abandoned airstrip could not be determined. Alexander Field at Belen is situated at an elevation of 5,194 feet msl (mean sea level)]. He said there was a tail wheel strike mark in the dirt 168 feet from the runway threshold. Just beyond were two dirt berms that had been struck by the airplane's main landing gear. On June 21, the FAA inspector partially disassembled and inspected the engine. He found the no. 2 cylinder compression ratio to be 45/80, due to exhaust blow-by. There was also a thin layer of carbon on the exhaust valve seat. The bottom no. 4 spark plug was 20 to 30% lead fouled, was wet with oil, and would not fire. After cleaning, the plug fired normally. In his report, the inspector said he found nothing "that would prohibit the engine from running in an 'as is' condition."
A loss of engine power due to low cylinder compression from an open exhaust valve, and the pilot's failure to lean the fuel mixture.
Source: NTSB Aviation Accident Database
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