Cessna 182P N78720 accident near Hyampom, California

Probable cause

The pilot’s failure to use carburetor heat, which resulted in a loss of engine power due to

carburetor icing and a subsequent impact with terrain during a forced landing.

NTSB analysis

The pilot overflew the destination airport at an altitude of about 8,500 ft mean sea level (msl) due to a temporary flight restriction. He then reduced the airplane’s engine power significantly, slowed the airplane’s airspeed, applied 10° of flaps, and initiated a 7,200-ft descent to the airport. While on approach to land, the pilot advanced the throttle but the engine did not respond. Unable to maintain altitude, he initiated a forced landing onto an open field about 900 ft south of the runway. During the landing roll on unimproved terrain, the nose landing gear separated and the airplane came to rest upright in a nose-down attitude, resulting in substantial damage to the forward fuselage.

During the recovery of the airplane, about 60 gallons of fuel was found remaining in its tanks; a postaccident examination of the airplane and engine did not reveal any pre-accident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

An NTSB meteorologist created a High Resolution Rapid Refresh (HRRR) model sounding for the accident time and location, with the modeled surface elevation at 1,277 ft msl. At an elevation of 7,064 ft msl, the HRRR sounding indicated the temperature was about 6.6°C and the dew point was about -5.9°C, with a relative humidity of 40%. The icing probability chart in FAA Special Airworthiness Information Bulletin CE-09-35 indicated that the modeled atmospheric conditions at the time of the accident were "conducive to icing at glide [idle] power," and the airplane’s prelanding checklist included applying full carburetor heat before the throttle was closed. However, the pilot stated that he did not use carburetor heat during the descent and approach.

Text from the NTSB. Open the NTSB docket for WPR25LA175 for the full record.