According to the pilot, a 100-hour inspection had just been completed on the Piper PA-28-181.
The pilot told investigators that the engine run-up was completed with no anomalies noted.
After liftoff, he remained in the traffic pattern for Runway 31 at Livingston County Spencer J Hardy Airport (KOZW) in Howell, Michigan.
The first traffic pattern and touch-and-go landing was uneventful.
On the second traffic pattern, the pilot extended his downwind leg by five seconds for spacing from another airplane in the traffic pattern. When he pilot reduced power and added 10° of flaps for the descent, he noticed that engine rpms had decreased to 900.
He attempted to restore engine power by turning on carburetor heat and verifying the electric fuel pump was on.
He was unable to restore engine power and transitioned to attempt a forced landing to Runway 31. During the forced landing attempt, he glided underneath powerlines and over the airport perimeter fence.
The airplane touched down in the grass short of Runway 31. It bounced on an embankment, hit the localizer antenna, and came to rest upright 1,000 feet before the arrival end of the runway.
The right wing separated at the wing root. The left wing was damaged and leaked fuel.
The carburetor linkage was connected and moved freely. The carburetor heat valve moved freely from open to closed.
The electric fuel pump was tested and fuel flow was noted from the output line. Fuel was present throughout the fuel system, carburetor, and fuel filters, and no water or debris was detected in the fuel. The engine-driven fuel pump was observed to pump fuel during engine rotation. The carburetor accelerator pump had positive pressure during manual actuation.
The fuel selector moved freely to all positions. The oil filter was new and appeared to be installed properly. An oil sample was obtained and no contaminants or metal were noted. The engine’s crankshaft was rotated by hand and internal and valvetrain continuity was established. The top spark plugs were removed from the cylinders and remained attached to the magneto leads. The spark plugs produced spark when the engine was rotated.
At 10:35 a.m., the weather reported at KOZW included a temperature of 22°C and a dew point of 20°C. The calculated relative humidity at that temperature and dewpoint was 88%.
Review of the icing probability chart contained in FAA Special Airworthiness Information Bulletin CE-09-35 revealed that the weather conditions at the time of the accident were “conducive to serious icing at glide [idle] power.”
According to FAA Advisory Circular 20-113, “To prevent accidents due to induction system icing, the pilot should regularly use carburetor heat under conditions known to be conducive to atmospheric icing and be alert at all times for indications of icing in the fuel system.”
The circular recommended that when operating in conditions where the relative humidity is greater than 50%, “…apply carburetor heat briefly immediately before takeoff, particularly with float type carburetors, to remove any ice which may have been accumulated during taxi and run-up.”
It also stated, “Remain alert for indications of induction system icing during takeoff and climb-out, especially when the relative humidity is above 50%, or when visible moisture is present in the atmosphere.”
Probable Cause: A loss of engine power due to the formation of carburetor ice that resulted from the pilot’s delayed use of carburetor heat during the landing approach.
NTSB Identification: 192460
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This June 2023 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.
