WPR11LA457

The pilot reported that he planned to accomplish a power-off landing to the runway and reduced engine power to idle during the descent from 9,000 feet to the traffic pattern altitude (3,700 feet). On final approach to the runway, the pilot applied carburetor heat. Shortly thereafter, the airplane descended below the glide path and the pilot increased engine power in an effort to correct the situation. The engine did not respond to the pilot’s inputs, and he subsequently landed short of the runway. The pilot reported that he suspected carburetor icing and that he should have applied carburetor heat immediately after retarding the throttle. However, the ground temperature and dew point at the time of the accident did not fall within the carburetor icing range. Postaccident examination of the engine and airframe revealed no preaccident mechanical malfunctions or failures that would have precluded normal operations.

HISTORY OF FLIGHT On September 17, 2011, about 1100 Pacific daylight time, a Cessna 170 airplane, N1677D, experienced a loss of engine power on final approach to Calvada Meadows Airport (NV74), Pahrump, Nevada. The pilot subsequently landed short of the intended runway and the airplane nosed over. The airline transport pilot was not injured. The airplane sustained substantial damage to the forward portion of the fuselage and wings. The airplane was registered to the pilot and operated as a personal flight under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the flight that originated from the North Las Vegas Airport (VGT), Las Vegas, Nevada, at 1030. The pilot reported that he planned to accomplish a power off landing to the runway and reduced engine power to idle during the descent to the traffic pattern (approximately 3,700 feet) from 9,000 feet. On final approach to the runway, the pilot completed a GUMPS (gas, undercarriage, mixture, propeller and seatbelts) check and applied carburetor heat. Shortly thereafter the pilot increased engine power in an effort to arrest the airplane’s descent rate on final approach; however, the engine did not respond to the pilot’s inputs and he subsequently landed short of the runway. The airplane collided with multiple small trees and a chain link fence before it nosed over. METEOROLOGICAL INFORMATION The weather conditions during the timeframe of the accident at Mercury, Nevada, located about 25 miles north of the accident site, was visibility 10 statute miles, clear skies, temperature 27 degrees Celsius (81 degrees Fahrenheit), dew point 2 degrees Celsius (36 degrees Fahrenheit) and an altimeter setting of 29.98 inches of Mercury. TESTS AND RESEARCH A postaccident examination was conducted on the airframe and engine. The exam revealed that all flight control surfaces were in place and control continuity was established. Throttle, mixture and carburetor heat cable control continuity was established and all associated linkage moved freely. The fuel selector valve was found in the “both” position and was intact and undamaged. Rotational continuity was established throughout the engine and valve train. Thumb compression was noted on all cylinders. Equal movement was noted on all of the intake and exhaust rocker arms. Internal examination of the piston cylinders, utilizing a lighted borescope, revealed no evidence of a mechanical malfunction. The magneto assemblies and ignition harnesses were in place and no damage was noted. The spark plugs produced spark when the crankshaft was manually rotated. The spark plugs were removed; a dark oil residue was noted to all spark plugs. The carburetor was disassembled. The carburetor bowl was empty of fuel. The floats and linkage assembly were undamaged and moved freely by hand. The fuel inlet screen was free of debris. The fuel line from the inline fuel strainer to the carburetorwas undamaged and pliable. The examination of the engine and airframe revealed no preaccident mechanical malfunctions or failures that would have precluded normal operations. An engine and airframe exam report is contained in the public docket. ADDITIONAL INFORMATION In a written report submitted to the NTSB the pilot reported that he suspected carburetor icing and that he should have applied carburetor heat immediately after retarding the throttle. The ground temperature and dew point at the time of the accident was 84 degrees Fahrenheit and 37 degrees Fahrenheit respectively. These values did not fall within the carburetor icing range when referenced against the FAA Special Airworthiness Information Bulletin CE-09-35, Carburetor Icing Prevention.