History of Flight
On March 24, 2021, at 0021 mountain daylight time, a Mooney M20B, registration N74786, was substantially damaged in an accident near Animas, New Mexico. The pilot and passenger sustained serious injuries. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 personal flight on an instrument flight rules (IFR) flight plan from Fort Stockton-Pecos County Airport (FST), Fort Stockton, Texas, to Tucson International Airport (TUS), Tucson, Arizona.
The pilot reported that while at 8,000 ft mean sea level (msl), the airplane was accumulating light rime ice. He contacted Albuquerque Air Route Traffic Control and was instructed to climb to 14,000 ft msl. During the climb, the pilot reported entering clouds; the engine began to run rough and lost partial power. He applied carburetor heat and checked both magnetos, believing both had failed.
Radio communication and radar contact were lost, prompting an alert notice (ALNOT). According to responding law enforcement, the airplane came to rest in mountainous terrain at an elevation of about 5,010 ft msl, approximately one mile northwest of the Pinkey Wright Mountains.
Meteorological Information
The closest recorded aviation weather station was Grant County Airport (KSVC), Silver City, New Mexico, about 44 miles northeast of the accident site at an elevation of 5,446 ft msl. Recorded weather at 0015 included wind from 300° at 9 knots, 10 miles visibility in light rain, a broken ceiling at 1,300 ft above ground level (agl), an overcast cloud layer at 2,200 ft agl, temperature 35°F, dew point 33°F, and altimeter 29.79 inches of mercury (inHg).
AIRMET advisories for mountain obscuration, moderate turbulence below 16,000 ft, and moderate icing between the freezing level and 20,000 ft msl were valid for the area at the time. The atmospheric sounding indicated an overcast layer of clouds with bases near 200 ft agl and tops to 16,000 ft msl, rain showers, and a freezing level of 1,400 ft agl (6,400 ft msl). Light rime to clear icing in clouds was identified between 6,400 ft and 16,000 ft.
The Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35 on carburetor icing prevention noted that carburetor ice can occur at temperatures above freezing due to fuel vaporization and air expansion causing sudden cooling. The bulletin included a chart indicating that conditions at the time were conducive to serious carburetor icing at cruise power.
Postaccident Examination
A postaccident examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation. The magnetos remained secured and attached to their mounting pads. Both magnetos were removed and manually rotated, with spark observed at each P-lead. Flight control continuity was established from the cockpit to all flight control surfaces via their respective cables and hardware.