NTSB Factual Report

On June 27, 2005, about 1720 eastern daylight time, a Cessna 177A, N70847, registered to and operated by NDM Enterprises, Inc., collided into trees and the ground following a loss of engine power in the vicinity of Rome, Georgia. The personal flight was operated under the provisions of Title 14 CFR Part 91 with an instrument flight rules plan filed. Visual meteorological conditions prevailed. The commercial pilot received serious injuries, the pilot-rated passenger received minor injuries, and the airplane sustained substantial damage. The personal flight departed Purdue University Airport, Lafayette, Indiana, about 1215 central daylight time.

The pilot stated the flight was en route to Richard B. Russell Airport, Rome, Georgia, and had cruised at 9,000 feet to the Chattanooga, Tennessee, area, then descended to 6,000 feet, and then to 4,000 feet. During descent about three nautical miles from Richard B. Russell Airport, the flight was at an approximate altitude of 3,400 feet when the pilot noticed the engine rpm had dropped to approximately 1000. The pilot attempted to restore engine power, and within 30 seconds, the engine stopped completely. The pilot stated the flight entered a small area of showers, and visibility was approximately three miles, and she could see the ground. The pilot stated she saw no suitable landing area within gliding distance, and she turned the airplane and glided it until it descended into trees and the ground.

Examination of the accident site revealed the wreckage was located in a heavily wooded area about the 1,200-foot elevation on Johns Mountain, about five nautical miles from Richard B. Russell Airport. The nose of the airplane was crushed aft, the right wing was crushed aft to the spar and partially separated at the wing root, the left wing was damaged, and the empennage was partially separated. Both wing fuel tank filler caps were secure. Fuel was recovered from the carburetor bowl, and from the fuel line between the fuel pump and the gascolator. Approximately one gallon of fuel was recovered from the fuel tanks; the recovered fuel appeared free of contaminants.

Examination of the engine revealed the spark plug electrodes exhibited no evidence of abnormal wear or contaminants, compression developed on all cylinders and valve train continuity was established when the engine was rotated by hand. The throttle, mixture, and carburetor heat controls were attached and functioned. Both magnetos produced ignition spark on each lead when rotated, and the induction system and filter were clear of obstructions. To facilitate a test run, the engine was removed from the airframe and stabilized, a serviceable propeller was installed, and an external source of fuel and electrical power was supplied. The engine was started and was run up to 1750 rpm; higher rpm testing was not performed. Examination of the airplane fuel system and lines from the engine to the tanks revealed no evidence of pre-impact leakage.

Review of the fueling records revealed the airplane's fuel tanks were topped off prior to departure; the airplane's usable fuel capacity was 48 gallons. Review of published induction system icing probability data for the temperature and dew point reported at the time of the accident revealed the conditions fell within "visible icing at rated power" and "serious icing at glide power." The data charts state, "icing conditions within the limits of the 'visible icing' curves may become 'serious' after 15 minutes continuous operation in such conditions." Review of the Cessna Owner's Manual for the Model 177, revealed the "Let-Down" checklist states, (1) Mixture - Rich. (2) Power - As desired. (3) Carburetor Heat - As required to prevent carburetor icing." The manual states in Section II, Operating Details, that carburetor ice is "... evidenced by an unexplained drop in RPM ... ."

NTSB Probable Cause

The pilot's delay in the use of carburetor heat, which resulted in the formation of carburetor / induction ice and the loss of engine power.