ERA11FA233

The pilot did not maintain minimum controllable airspeed while on final approach with a partial loss of power in the right engine, which resulted in a loss of control. Contributing to the accident was the partial loss of engine power in the right engine due to the improperly installed o-rings in the engine’s throttle and control assembly.

The multi-engine airplane was being repositioned to its base airport, and the pilot had requested to change the destination, but gave no reason for the destination change. Radar data indicated that the airplane entered the left downwind leg of the traffic pattern, flew at pattern attitude, and then performed a right approximate 250-degree turn to enter the final leg of the approach. During the final leg of the approach, the airplane crashed short of the runway into a house located in a residential neighborhood near the airport. According to the airplane's pilot operating handbook, the minimum multi-engine approach speed was 95 knots indicated airspeed (KIAS), and the minimum controllable airspeed was 82 KIAS. According to radar data, the airplane's groundspeed was about 69 knots with the probability of a direct crosswind. Postaccident examination of the propellers indicated that both propellers were turning at a low power setting at impact. During a controlled test run of the right engine, a partial power loss was noted. After examination of the throttle and control assembly, two o-rings within the assembly were found to be damaged. The o-rings were replaced with comparable o-rings and the assembly was reinstalled. During the subsequent test run, the engine operated smoothly with no noted anomalies. Examination of the o-rings revealed that the damage was consistent with the o-rings being pinched between the corner of the top o-ring groove and the fuel inlet surface during installation. It is probable that the right engine had a partial loss of engine power while on final approach to the runway due to the damaged o-ring and that the pilot retarded the engine power to prevent the airplane from rolling to the right. The investigation found no mechanical malfunction of the left engine that would have prevented the airplane from maintaining the published airspeed.

HISTORY OF FLIGHT On April 10, 2011, about 1815 eastern daylight time, a Cessna 402B, N402RC, was substantially damaged when it impacted a house near Biddeford, Maine. The airline transport certificated pilot was fatally injured. The airplane was registered to My Plane, LLC, and operated under the provisions of 14 Code of Federal Regulation 91 as a positioning flight. Visual meteorological conditions prevailed and no flight plan had been filed. The airplane had departed from West Chester County Airport (HPN), White Plains, New York, about 1630. The flight originated at Portland International Airport (PWM), Portland, Maine earlier in the day, flew to Nantucket Memorial Airport (ACK), Nantucket, Massachusetts, and acquired 115.6 gallons of 100LL aviation fuel. Then picked up a passenger, flew to HPN, where the passenger disembarked, departed and the pilot was planning to land in PWM. According to Federal Aviation Administration (FAA) Air Traffic Control transcripts, the pilot requested to change his destination to Biddeford Municipal Airport (B19), Biddeford, Maine. Radar data provided by the FAA Portland Air Traffic Control facility, revealed that the airplane overflew the south end of B19 at approximately 1,000 feet above mean sea level (msl), turned left, as if entering the left downwind leg of the airport traffic pattern. Then, approximately 2 miles from the approach end of runway 24, the airplane was observed, on radar, turning right about 250 degrees, and then a slight left turn in the direction of B19. The last radar data was recorded for the accident flight at 1804:29 and was in the vicinity of the accident location. The data indicated an altitude of 400 feet msl and a ground speed of 69 knots. PERSONNEL INFORMATION According to FAA records, the pilot, age 71, held an Airline Transport pilot certificate with a rating for airplane multiengine land, commercial pilot privilege for airplane single-engine land, and a certificated flight instructor with ratings for airplane single-engine land, multiengine land, and instrument airplane. His most recent FAA second-class medical certificate was issued February 4, 2011, and at the time of the examination the pilot reported 5,010 total hours of flight experience. According to a resume provided to the pilot's employer in August 2010, the pilot reported 4,735 total hours of civilian flight time as well as military navigator flight time. The resume also indicated 120 flight hours in the accident aircraft make and model. At the time of this writing no pilot logbooks had been located. AIRCRAFT INFORMATION According to FAA records, the airplane was manufactured in 1977 and registered to the owner on October 18, 2000. It was equipped with two Continental Motors TSIO-520 series engines. The airplane's most recent annual inspection was dated on August 21, 2010. At the time of the inspection the reported aircraft total time was 6,624.5 time in service and a Hobbs time of 4,554.1 hours. At the time of the inspection the engines had 359.0 hours since overhaul. The most recent maintenance logbook entry was March 21, 2011, and indicated a Hobbs time of 4,567.2 hours. The Hobbs meter was not located in the wreckage. METEOROLOGICAL INFORMATION The 1815 recorded weather observation at Sanford Regional Airport (SFM), Sanford, Maine, located approximately 16 miles to the southwest of the accident location, included wind from 150 degrees at 8 knots with gusts of 15 knots, the wind direction was variable from 100 degrees to 160 degrees, visibility 10 miles, clear skies, temperature 14 degrees C, dew point minus 2 degrees C; barometric altimeter 30.03 inches of mercury. AIRPORT INFORMATION The airport was equipped with a single runway oriented northeast to southwest and designated as 06/24. The runway was 3000-feet-long and 75-feet-wide, constructed of asphalt, was equipped with a 4-box visual approach slope indicator (VASI) on the left side of runway 6; however, no visual slope indicators were available to runway 24. The airport did not have an air traffic control tower. Communication was accomplished utilizing a common traffic advisory frequency; however, it was not recorded. The airport was served by two approaches to runway 6; however, runway 24 was the preferred calm wind runway. WRECKAGE AND IMPACT INFORMATION The airplane impacted four trees varying in diameter from 3.2 inches to 8.75 inches and at a height of approximately 25 feet. The airplane came to rest on the roof of a single story residence that was located approximately 1,491 feet to the northeast of the runway 24 threshold. A post crash fire ensued engulfing the airplane. The left wing was thermally damaged and the outboard section of the wing was located on top of the roof. The left engine was located inside the residence. The right wing and engine were visible above the roof line. The airplane nose section, cabin, and empennage sections were thermally damaged. Portions of all flight controls were located at the accident location. Examination of the wreckage indicated that the right main landing gear remained attached to the right wing attach point, and was in the down and locked position. The left main and nose gear were separated from the airframe and located within the residence. The left wing's leading edge exhibited impact damage and the diameter of the damage was similar in dimensions to the diameter of the trees that were initially impacted. The left aileron was consumed by post impact fire. The fuel caps were secured and in place. The fuel tank selector handle located in the cockpit was found in the auxiliary tank position and the fuel valve located in the wing was found between the main and auxiliary tank position. The fuel strainer and filter were thermally damaged and had an area of corrosion in the bottom of the strainer approximately 30 degrees of coverage. The right wing's aileron was separated and in the vicinity of the right wing. The right wing's outboard section approximately 2 feet inside the main fuel tank, located at the wingtip, was fractured but remained attached to the wing structure. The right main fuel tank was impact damaged near the leading edge of the tank. The right fuel tank selector handle, which was located in the cockpit and the fuel valve located in the wing, were in the main fuel tank position. The fuel strainer was removed from the wing and contained aviation gasoline, the filter was free of debris. The fuel strainer was noted as having an area of corrosion located in the bottom of the strainer and was approximately 30 degrees of coverage and was similar in appearance as the left fuel strainer. The wing flaps were found in the extended position and were verified by the flap motor chain position located under the cabin floor. Continuity was confirmed from the flap motor to the flap actuator. The right wing flap remained attached to the wing, the left wing flap mechanism remained attached; however, the flap skin was consumed by post impact fire. The cockpit seats were separated and thermally damaged. Four of the five cabin seat frames remained attached to the cabin floor except for the most aft cabin seat which was located with portions of the flooring still attached to the seat feet. Rudder continuity was confirmed from the rudder pedals to the rudder horn. The rudder counter weight was located in the wreckage in the vicinity of the empennage. Aileron continuity was confirmed from the cabin chain on the control columns to the aileron sector and then from the aileron sector to both ailerons bell cranks. The aileron sector was impact damaged in the positive direction. The aileron counter weights were located in the vicinity of the associated wing or attached to the wing. Elevator continuity was confirmed from the elevator horn to the swaged end of the cable. The right elevator counter weight remained attached; however, due to thermal damage the left counter weig