On March 29, 1989, a Piper PA-16 (registration N5368H) was involved in an aviation accident near Danville, GA. Investigators recorded the probable cause as: THE PILOT DELAYED IN APPLYING CARBURETOR HEAT AFTER THE ENGINE BEGAN TO LOSE POWER, AND HIS SELECTION OF UNSUITABLE TERRAIN FOR A PRECAUTIONARY-LANDING SITE. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During cruise, an engine lost power; the pilot applied carb heat and made a precautionary landing in an uneven field, but could not stop before hitting a fence.
Event Details
The pilot reported that during cruise, the engine began to lose power (RPM) as if experiencing a bad case of carburetor icing. The pilot applied carburetor heat after the engine had lost over 300 RPM. Despite this action, the engine continued to lose power, leading the pilot to elect a precautionary landing in an open field. The field was uneven, and the pilot found that he could not brake the airplane to a stop before colliding with a fence. According to the pilot, the total elapsed time from the initial power loss to landing was only 2 to 3 minutes.
Engine Examination
Examination of the engine revealed black, sooty deposits on the firing ends of the spark plugs. According to icing probability curves, conditions were favorable for the formation of moderate icing at cruise power. The airplane was equipped with a Supplemental Type Certificate (STC) to operate on autogas, and it was fueled with a mixture of 100LL avgas and auto gas.