WPR12LA128

According to the pilot, he began his descent from 3,000 feet mean sea level (msl) by lowering the landing gear and reducing the power on both engines. When the airplane reached an altitude of about 1,200 feet msl, the left engine lost power. The pilot was about to feather the left propeller when engine power was momentarily restored followed by both engines losing power. He selected a “dark space” on the ground and performed a forced landing. During the landing, the airplane collided with a ditch and a fence. Postaccident examination of the engines revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. About the time of the accident, a weather station about 4 nautical miles from the accident site reported a temperature of 52 degrees F and dew point of 45 degrees F. These weather conditions were conducive to the formation of serious carburetor icing at cruise and glide power settings. The pilot did not report applying carburetor heat when he initiated the descent, during descent, or following the loss of engine power. Additionally, the pilot stated that he believed carburetor icing caused both engines to lose power.

On March 10, 2012, about 1925 Pacific standard time, a Beech 76, N6697L, sustained substantial damage following a dual engine power loss and subsequent forced landing near Rio Linda, California. The airline transport pilot and his two passengers were not injured. The pilot was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Night visual meteorological conditions prevailed for the personal cross-country flight, which had originated from Visalia, California, about 1810, with an intended destination of McClellan Airfield, Sacramento, California. A flight plan had not been filed. The pilot reported that he began to descend from his en route altitude of 3,000 feet mean sea level by lowering the landing gear and reducing power on both engines to 18 inches of manifold pressure. When the airplane reached an altitude of about 1,200 feet msl, the left engine lost power. The pilot advanced the power, propeller, and mixture controls full forward and was about to feather the left propeller when the engine “came alive for a couple of seconds,” and then both engines lost power. He selected a dark space on the ground and performed a forced landing. During the landing, the airplane collided with a ditch and a fence. The airplane’s right wing was separated from the fuselage, and the fuselage and left wing were bent and wrinkled. Local fire department personnel who responded to the accident site reported that the right wing fuel tank was breached, and they observed about 5 gallons of fluid flow out of the tank. A local law enforcement officer removed the left wing fuel tank cap, looked in the opening, and was unable to see any fuel. Review of photographs of the airplane at the accident site taken by Federal Aviation Administration (FAA) inspectors the day after the accident revealed damage to the left wing consistent with the left wing fuel tank being breached. Additionally, the photographs showed that the left wing was displaced from the fuselage and tilted so that the left wing tip was raised above its normal position, which would have precluded an accurate determination of the quantity of fuel in the left wing tank by looking into the fuel filler opening. On May 15, 2012, a Federal Aviation Administration (FAA) inspector examined the airplane’s engines. The examination revealed no evidence of any pre-impact mechanical malfunctions or failures that would have prevented normal operation of the engines. A report of the examination is contained in the public docket for this accident. At 1915, McClellan Airfield, located 4 nautical miles southeast of the accident site, was reporting a temperature of 52 degrees F and a dew point of 45 degrees F. For these conditions, the carburetor icing probability chart from DOT/FAA/CT-82/44 Publication: Light Aircraft Piston Engine Carburetor Ice Detector/Warning Device Sensitivity/Effectiveness, June 1982, shows a probability of serious icing at cruise and glide power settings. The pilotstated that he felt “the only cause to lose both engines within a few seconds could be carburetor icing.” The pilot did not report applying carburetor heat when he initiated descent, during descent, or following the loss of engine power.