CEN23LA266

The pilot reported that during a local flight, while in the traffic pattern, the airplane’s engine power decreased to 900 rpm. He attempted to restore engine power but was unsuccessful and attempted to make a forced landing to the runway. He landed on the grass about 1,000 ft short of the runway surface, bounced, and impacted the localizer antenna. The airplane sustained substantial damage to the fuselage and both wings. Postaccident examination of the engine and fuel systems revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The weather conditions at the time of the accident were conducive to a serious accumulation of carburetor ice at glide power. The pilot reported that he used carburetor heat while attempting to restore engine power, but not before he made his descent in the traffic pattern and the loss of engine power. Based on the available information, the loss of engine power was likely due to carburetor ice accumulation. Additionally, the low altitude at which the loss of engine power occurred significantly reduced the amount of time available to the pilot to troubleshoot and restore engine power before the forced landing.

On June 24, 2023, about 1030 eastern daylight time, a Piper PA-28-181, N4008Q, was substantially damaged when it was involved in an accident near Livingston County Spencer J Hardy Airport (OZW), Howell, Michigan. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, a 100-hour inspection had just been completed. The pilot reported that the engine run-up was completed with no anomalies noted. After liftoff, the pilot remained in the traffic pattern for runway 31 at OZW. 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 the pilot reduced power and added 10° of flaps for the descent, he noticed that engine rpms had decreased to 900. The pilot attempted to restore engine power by turning on carburetor heat and verifying the electric fuel pump was on. The pilot was unable to restore engine power and transitioned to attempt a forced landing to runway 31. During the forced landing attempt, the pilot glided underneath powerlines and over the airport perimeter fence. The airplane touched down in the grass short of runway 31. The airplane bounced on an embankment, impacted the localizer antenna, and came to rest upright. The airplane came to rest 1,000 ft before the arrival end of runway 31. The right wing separated at the wing root. The left wing was damaged and leaked fuel. A postaccident examination did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation. 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 1035, the weather reported at OZW 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 Federal Aviation Administration (FAA) Special Airworthiness Information Bulletin CE-09-35 revealed that the weather conditions at the time of the accident were "conducive toserious 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 runup." It also stated, "Remain alert for indications of induction system icing during takeoff and climb-out, especially when the relative humidity is above 50 percent, or when visible moisture is present in the atmosphere."