Incident Details
A flight instructor and a student pilot were on a long cross-country flight when they encountered deteriorating weather conditions. To remain in visual flight rules (VFR), they altered their course and destination. While approaching a ridge line, the flight instructor noticed that the airplane's airspeed began to drop toward 65 miles per hour. Suspecting carburetor ice, he reached for and pulled out the carburetor heat control.
The student pilot reported that after the instructor said, "watch your airspeed," he observed the revolutions per minute (RPM) gauge indicating between 1800 and 1900 RPM. The flight instructor then took over the flight controls. Shortly thereafter, the airplane impacted the top of the ridge.
Weather Conditions
A review of multiple weather observation stations located around the four corners of the accident site revealed similar conditions: temperature 55°F and dew point 43°F. The Federal Aviation Administration (FAA) Carburetor Icing Chart for these temperature and dew point values indicated that the conditions were conducive to "serious icing at cruise power." (Additional information is available in Special Airworthiness Information Bulletin CE-09-35 in the public docket.)
Aircraft Damage
The airplane sustained substantial damage to the right wing.