Aviation Accident Summaries

Aviation Accident Summary WPR22LA064

Tooele, UT, USA

Aircraft #1

N4370W

BEECH A36

Analysis

The pilot stated that he began a descent to pattern altitude at the destination airport. When he reduced the propeller speed to 2,200 rpm, a “slapping sort of knock began as well as a shimmy in the plane.” The pilot arrested the descent, observed that the oil temperature and oil pressure were normal, and looked outside the airplane to verify that the flight control surfaces had no issues. The pilot then noticed that the airspeed had decreased to 130 miles per hour and that the controls became “heavy and very mushy.” The pilot initiated a forced landing to a nearby road but abandoned that plan when he observed a vehicle traveling on the road. The pilot advanced the propeller and throttle levers full forward but received no response from the engine, and he noticed that the cylinder head temperature gauge had “dropped completely to the left.” The pilot maneuvered the airplane to avoid power lines and landed in an open desert area. During the landing, the airplane struck trees, impacted terrain, and came to rest at a nose-low attitude. Postaccident examination of the airframe and engine revealed no evidence of any pre-existing mechanical malfunction that would have precluded normal operation. Utilizing the reported fuel quantity at the time of departure and fuel burn rate for the reported power setting, it was determined that the pilot had an adequate amount of fuel for the intended flight. As a result, the reason for the total loss of engine power could not be determined.

Factual Information

On November 24, 2021, about 1240 mountain standard time, a Beech A36, N4370W, was substantially damaged when it was involved in an accident near Tooele Valley Airport (TVY), Tooele, Utah. The pilot and three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the airplane departed from Safford, Arizona, with 80 gallons of fuel aboard. The pilot reported that, during cruise flight at 12,500 ft mean sea level (msl), he used a 65% power setting, consistent with the power setting in the Pilot Operating Handbook (POH) for that phase of flight. As the airplane neared Gunnison, Utah, which was about 85 miles south of TVY, he switched from the right fuel tank to the left fuel tank. Shortly afterward, the pilot initiated descents to 10,500 ft msl and then 8,500 ft msl while west of Provo, Utah. The pilot stated that he maintained a mixture setting of 50° rich of peak throughout the descent. As the airplane neared the Tooele Valley, he descended the airplane to 6,500 ft msl and maneuvered around a ridgeline. While descending to pattern altitude at the destination airport, the pilot reduced the propeller speed to 2,200 rpm, at which time a “slapping' sort of knock began, as well as a shimmy in the plane.” The pilot arrested the descent and observed that the oil temperature and oil pressure were normal. He then looked outside the airplane and verified that no control surface issues were occurring. Afterward, the pilot focused his attention on engine performance. The pilot stated that the airspeed had decreased to 130 miles per hour and that the controls became “heavy and very mushy.” The pilot initiated a forced landing to a nearby road, but he observed a vehicle that was traveling on the opposite direction of the road and decided not to land there. The pilot then advanced the propeller and throttle levers full forward but received no response from the engine. The pilot also noticed that the cylinder head temperature gauge had “dropped completely to the left of the gauge.” The pilot stated that he pitched the airplane upward to avoid power lines and landed in an open desert area. During the landing, the airplane struck multiple juniper trees before it impacted terrain and came to rest nose low, which resulted in substantial damage to the left wing. The airplane was equipped with two 40-gallon fuel tanks, of which, 74 gallons of fuel is usable. The POH indicated that at a 65% cruise power setting, fuel burn is between 10.0 and 13.3 gallons per hour. Postaccident examination of the airframe and engine revealed no evidence of any pre-existing mechanical malfunction that would have precluded normal operation of the engine.

Probable Cause and Findings

The total loss of engine power for reasons that could not be determined based on available evidence.

 

Source: NTSB Aviation Accident Database

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