History of Flight
On February 4, 2012, at 1315 mountain standard time, a Piper PA-28R-201T, registration N38906, experienced a partial loss of engine power shortly after takeoff from Kalispell City Airport in Kalispell, Montana. The pilot initiated a forced landing on a residential street. During the landing, the airplane collided with parked vehicles and a residence. The airplane was registered to the pilot and operated under Title 14 Code of Federal Regulations Part 91. The commercial pilot and his two passengers received minor injuries, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and no flight plan had been filed.
The pilot stated to the National Transportation Safety Board investigator-in-charge that he fueled the airplane with 45 gallons of AVGAS, taxied to pick up his passengers, and performed a complete engine run-up and preflight checks. During takeoff, the airplane behaved normally and accelerated smoothly. After takeoff, between 300 and 500 feet above ground level over a residential area, the engine started to sputter and lose power. The pilot selected the longest street on which he could make a forced landing, lowered the flaps, and slowed the airplane to minimum controllable airspeed. The airplane collided with a number of vehicles and trees; the left wing separated from the fuselage. The airplane rotated inverted and embedded itself into the front of a house. The pilot egressed through the pilot's side window and assisted with the egress of his passengers.
Aircraft Information
The low-wing, four-seat, retractable landing gear airplane, serial number 28R-7703283, was manufactured in 1977. It was powered by a Continental Motors Incorporated TSIO-360-F, serial number 305278, 200-hp engine, equipped with a Hartzell model BHC-C2YF-1BF constant speed propeller. A review of the airplane's maintenance records showed that an engine overhaul was completed on July 18, 1989. An annual inspection was completed on July 29, 2011, at a recorded tachometer time of 1,770.3 hours, and time since major overhaul of 322.3 hours. The tach time observed at the accident site was 1,772.65.
Wreckage and Impact
The main wreckage consisted of the fuselage, engine, tail, and right wing, which impacted a residence at ground level. The left wing had been sheared off at the wing root by a parked pickup truck located approximately 50 yards further up the airplane's line of travel. Light blue colored fluid was observed leaking out of the severed wing. There was no post-accident fire. The engine and cockpit area of the airplane was embedded into the building structure. The following day, February 5, the airplane was recovered and moved to a storage location in Belgrade, Montana. During recovery, approximately 45 gallons of AVGAS was recovered from both wing tanks combined.
On February 22, 2012, technical representatives from the airframe and engine manufacturer examined the airplane under the oversight of a Federal Aviation Administration inspector. Both ailerons were attached to their respective wing, and control cables were attached to both aileron bell cranks. The horizontal and vertical tail surfaces remained attached; the rudder and stabilator remained attached. The fuel selector handle was in the left tank position; the throttle and mixture control levers were full forward. The AUX fuel pump switch was in the center OFF position. The auxiliary electric fuel pump was functionally tested and found to function normally on both low and high power settings. The fuel gascolator bowl contained bluish fluid consistent with AVGAS. Engine power-train continuity was established by rotating the crankshaft. The engine-driven fuel pump was tested and found to function normally. The magnetos remained attached and both produced spark at all ignition leads when the crankshaft was rotated by hand.
The airframe manufacturer technical representative reported that the airframe revealed no pre-impact failure to any flight control surface or system component. The engine manufacturer technical representative reported that inspection did not reveal any anomalies that would have prevented the engine from producing rated horsepower.
Tests and Research
A surveillance video camera mounted on an airport hangar captured the airplane’s takeoff departure path. The video shows an airplane immediately after takeoff moving at a constant altitude approximately 75 feet above ground level from right to left across the screen at a constant speed.
Under the direction of the NTSB IIC, an Airframe & Powerplant mechanic removed both magnetos from the engine on April 5, 2013. Both magnetos were Bendix model S6LN-25. On April 15, 2013, under FAA supervision, both magnetos were tested at normal operating speeds. The right magneto, serial number A186072, produced spark on all posts. The left magneto, serial number A186084, produced spark on one post. Disassembly revealed a worn bushing. The magneto was sent to the Analytical Department of Continental Motors, Inc. and examined under NTSB supervision. CMI technical experts determined that the magneto’s distributor block bushing was worn to an extent that provided significant radial play between the bushing and distributor block. The bushing, which holds the distributor gear axle in place, was worn to such an extent that it would permit the distributor gear to intermittently disengage from the drive gear. Once disengaged, the internal timing of the magneto would be off, which could disrupt the normal ignition sequence and engine operation.
Review of engine maintenance records showed the magneto was last overhauled on July 18, 1989, and had accumulated 324.65 hours since overhaul. The S-20 Series Magneto Service Support Manual recommends magnetos be inspected after the first 500 hours in service and every 500 hours thereafter, and overhauled or replaced 5 years after date of manufacture or last overhaul, or 4 years after date placed in service, whichever occurs first, without regard to accumulated operating hours.