Accident Overview
On May 16, 2024, at approximately 0900 Pacific daylight time, a Cessna 172G airplane, registration N4448L, was substantially damaged in an accident near Lakeport, California. The pilot, who was the sole occupant, reported no injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Flight Sequence
The pilot had been conducting full-stop landings at Lampson Field Airport (1O2) in Lakeport. After three takeoffs and landings, he taxied to his hangar and decided to perform one additional flight in the traffic pattern. He then taxied to the run-up area and performed a pre-departure run-up, which included a magneto check and activation of carburetor heat; both checks resulted in an rpm drop.
On the accident flight, the airplane reached rotation speed and lifted off normally. During the initial climb, the engine lost power and the airplane stopped climbing. The pilot determined he was too low to turn back to the runway and opted to continue straight ahead, initiating a forced landing to an open field. During the landing sequence, the empennage struck a barbed wire fence and separated from the fuselage.
Weather Conditions
The nearest weather reporting station was Ukiah Municipal Airport (UKI), Ukiah, California, located 16 nautical miles northwest of the accident site. At 0856, the reported temperature was 55.4°F with a dewpoint of 50°F, yielding a calculated relative humidity of about 82%.
Relevant Advisories
FAA Special Airworthiness Information Bulletin (SAIB) CE-09-35, Carburetor Icing Prevention, indicates that atmospheric conditions such as those present at the time of the accident are conducive to serious icing at cruise power. The bulletin notes that carburetor icing can occur at temperatures well above freezing when visible moisture or high humidity is present, due to the cooling effect from fuel vaporization and air expansion in the carburetor.
Additionally, FAA Advisory Circular (AC) 20-113 recommends that pilots regularly use carburetor heat under conditions known to be conducive to atmospheric icing, and specifically advises that when relative humidity exceeds 50% and temperature is below 70°F, pilots should apply carburetor heat immediately before takeoff to remove any ice accumulated during taxi and run-up, and remain alert for induction system icing during takeoff and climb-out.
Postaccident Examination
Postaccident examination of the engine revealed no obvious holes in the crankcase. The fuel system showed no breaches, and continuity was confirmed from the wings to the carburetor. Borescope inspection of each cylinder revealed no evidence of mechanical failure of pistons or valves. Spark plugs exhibited normal wear according to the Champion Aviation Check-A-Plug Chart AV-27, except the No. 5 bottom spark plug, which was carbon/oil fouled. The engine was started and run for about 3 minutes at idle rpm; a full run-up was not performed due to damaged propeller blades. Functional checks of the magnetos and carburetor heat showed a normal rpm drop, and the power loss could not be replicated. The examination found no preaccident mechanical malfunctions or failures that would have precluded normal operation.
Probable Cause
The investigation did not identify a probable cause for the engine power loss.