This April 2007 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Grumman Yankee.
Location: Lakeland, Fla.
Injuries: 1 Minor.
Aircraft damage: Substantial.
What reportedly happened: The airplane was on approach for landing. The pilot noticed the engine rpm decreasing and the cylinder head temperature increasing. He realized the engine was losing power and that he lacked sufficient altitude to glide to an airport, so he performed a forced landing in a field.
After the accident, 37 ounces of oil were drained from the engine. Metal and carbon was noted in the oil screen, which was stuck in the housing. There was no evidence of an oil leak. The pilot told investigators that when he started the flight the oil quantity was between 5.5 and 5.75 quarts.
Disassembly of the engine revealed damage consistent with inadequate oil.
Probable cause: The pilot’s inadequate preflight inspection and failure to determine the oil level.
For more information: ntsb.gov/ntsb/brief.asp?ev_id=20070418X00430&key=1.