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On July 23, 2011, at 0830 mountain daylight time, a Hawker Beechcraft G36 Bonanza, N536BB, sustained substantial damage following a loss of engine power and subsequent forced landing at Friedman Memorial Airport (KSUN), Hailey, Idaho. The airplane was registered to, and operated by the pilot under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot, the sole occupant of the airplane, was not injured. The pilot's planned destination was Aurora State Airport, Aurora, Oregon. Visual meteorological conditions (VMC) prevailed and an instrument flight plan was activated.
The pilot reported that shortly after takeoff he retracted the landing gear and the engine lost power about 100 feet above ground level. The pilot then lowered the landing gear and landed on the remaining runway. He reported that the airplane was 20 to 25-degrees left of runway heading when it touched down; the airplane subsequently exited the runway and collided with a taxiway sign before it came to rest.
The airplane sustained substantial damage to the left wing.
The 58-year-old pilot held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. The pilot reported that his total flight experience was 314 hours, with 111 hours in the accident airplane make and model.
The pilot held a third-class medical certificate issued in September 2009. The medical certificate carried a limitation that required he have reading glasses available.
The G36 Bonanza, serial number E-3854, was a six-place, low-wing, retractable gear airplane manufactured in 2008. The airplane was equipped with a Garmin G1000 integrated flight instrument system that incorporated a primary flight display (PFD) and a multi-function display (MFD).
A review of the maintenance logbooks revealed that the most recent annual inspection of the airframe was performed on June 8, 2011 at a total time of 439 hours. The most recent annual inspection of the engine was performed on June 8, 2011 at a total time of 439 hours.
The airplane was delivered from the factory powered by a Continental Motors IO-550-B engine, rated at 300 horsepower (naturally aspirated). On July 30, 2008 the airplane was retrofitted with a Tornado Alley Turbo, Inc., “Whirlwind System II” turbo normalizing system. The airplanes total time at installation was 7.7 hours.
The weather at KSUN during the timeframe of the accident was a temperature of 63 degrees Fahrenheit, a dew point of 28 degrees Fahrenheit and clear skies. The altimeter setting was 30.19 inches hg.
Friedman Memorial Airport is located in a mountainous region at a field elevation of 5,320 feet. The airport has two hard-surfaced runways, 13 and 31 respectively, that are 7,550 feet in length.
TESTS AND RESEARCH
The Garmin G1000 integrated flight instrument system data was extracted by personnel from the National Transportation Safety Board’s Vehicle Recorder Division. The G1000 recorded flight and engine data for the time between engine start and the accident. The data revealed, in part, that during takeoff and initial climb the engine’s fuel flow supply increased from approximately 35 gallons per hour (gph) to approximately 45 gph. Shortly thereafter, the engines exhaust gas temperatures (egt) and rotations per minute (rpm) decreased to sub idle parameters.
Postaccident examination revealed no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.
An engine and airframe examination report and recorded flight data report is contained in the public docket for this case file.
The airplane is equipped with a dual speed, dual pressure, electric vane type auxiliary fuel pump. The pump is controlled by a single, three-position switch located on the pilot’s subpanel to the left of the landing gear handle. A placard on the instrument panel above the auxiliary fuel pump switch reads “AUX FUEL PUMP OPERATION - TAKE OFF AND LAND WITH AUX FUEL PUMP OFF EXCEPT IN CASE OF LOSS OF FUEL PRESSURE.”
The Federal Aviation Administration (FAA) Approved Airplane Flight Manual Supplement for the airplane (supplied by Tornado Alley) states that the auxiliary fuel pump should be in the off position for takeoff operations below a density altitude of 5,000 feet, and set to the low position for takeoff operations above a density altitude of 5,000 feet. The supplement also instructs pilots to manually lean the mixture to 35 gph if the fuel flow exceeds 35 gph.
The Flight Manual Supplement includes a warning that reads “use of the auxiliary fuel pump in the HI position may cause an excessively rich mixture and severely reduce available engine power or even cause the engine to cease combustion completely. The HI position should not be used for take-off unless there is a failure of the engine driven fuel pump.”
The airplane has two separate fuel flow displays in the cockpit: an analog display that is installed as part of the turbo normalizer installation and a digital readout that is part of the G1000 integrated flight instrument system installation. The turbo normalizer analog fuel flow display is located on the pedestal just below the engine control levers. The G1000 integrated flight instrument system in the G36 airplane displays fuel flow to the pilot digitally on the G100 displays mounted on the instrument panel. The analog display has an upper fuel flow limit (depicted in red) of 35 gph. The digital display incorporates an upper limit and displays in red for fuel flow indication above 27.4 gph; the digital display also incorporated an aural chime if the upper limit of 27.4 gallons is exceeded. The Flight Manual Supplement (Tornado Alley) instructs pilots to use the analog display as the primary indication of fuel flow.
The 27.4 gph fuel flow limit displayed on the G1000, and the aural warning, is predicated on the original factory installed engine induction system, not the turbo normalizing induction system.
Engines equipped with the turbo normalizer system have fuel flow rates (nominal takeoff) that exceed 27.4 gph, and consequently both the aural fuel flow warning and digital display warning will activate.
The pilot reported that during the takeoff roll he observed the digital fuel flow display in red and received the aural warning. He also reported that he may have inadvertently switched the auxiliary fuel pump to the HI position during takeoff.