Gypsum, KS, USA
N3045R
THRUSH AIRCRAFT INC S2R-H80
The commercial pilot stated that, after completing a portion of a low-level agricultural application flight, the engine power decreased "significantly." The pilot pushed the power lever full forward, but the engine did not respond. He made several more passes to get more weight off the airplane to see if the engine would regain power; however, engine power did not increase, so the pilot flew the airplane back toward the departure airport. The pilot tried to climb the airplane but there was insufficient power to do so, and he then saw smoke coming out both exhausts. The engine then lost all power. Subsequently, the pilot conducted a forced landing in a field, and the airplane slid through a fence and then stopped, which resulted in substantial damage to the fuselage. A review of data downloaded from the engine monitor revealed engine operation consistent with a fuel interruption and a subsequent loss of engine power. During postaccident examination, the main electric fuel boost pump was found operational. However, it did not meet standard acceptance test criteria. The engine was not test run; however, component level testing of the fuel control unit, the emergency electric fuel pump, and the starting and limiting unit revealed no anomalies that would have prevented normal operation. Thus, the reason for the interruption in fuel flow and the subsequent loss of engine power could not be determined. However, the airplane manufacturer has subsequently developed a redesign and has issued a service bulletin to address the fuel system, including electric fuel pumps and plumbing. The Airplane Flight Manual (AFM) contained a Failure of Automatic Fuel Scheduling checklist, and the first step of this checklist was to engage the emergency governor. The pilot reported that he did not follow these procedures when the engine power decreased. Further, the AFM contained an Engine Failure In-Flight checklist, and the first step of the checklist was to dump the hopper. The pilot reported that he did not dump the hopper when the engine lost power. The pilot's failure to subsequently follow the emergency procedures to recover engine power likely necessitated the forced landing.
HISTORY OF FLIGHTOn May 5, 2017, about 1450 central daylight time, a Thrush Aircraft Inc. S2R-H80 airplane, N3045R, impacted terrain and a fence during a forced landing near Gypsum, Kansas, following a loss of engine power. The commercial pilot was uninjured. The airplane sustained substantial fuselage damage during the forced landing. The airplane was registered to and operated by Central Ag Air LLC as a Title 14 Code of Federal Regulations Part 137 aerial application flight. Day visual meteorological conditions prevailed in the area about the time of the accident, and the flight was not operated on a flight plan. The local flight originated from the Marion Municipal Airport (43K), near Marion, Kansas, about 1350. The pilot reported that he departed 43K to perform an aerial application approximately 35 miles to the northwest. He sprayed two fields before reaching another field where he intended to perform the aerial application. During a pass through the field, the engine power decreased "significantly." The pilot reached over and pushed the power lever full forward and the engine did not respond. He continued to make several more passes to get more weight off the airplane and see if the engine would regain power. The engine did not get any better, so the pilot flew the airplane up out of the field and headed back to 43K. The pilot tried to climb but the airplane did not have enough power to climb. The airplane made it about 2 miles and then the smoke started coming out both exhausts and the engine "quit." The pilot observed the surrounding area, which was "big rolling hills and terraced farmland," and decided the best place for a forced landing was an alfalfa field. The airplane touched down in the corner of the alfalfa field and a pasture. The airplane slid to rest in the alfalfa field after sliding through a fence. When the airplane came to a stop, the pilot reached down, turned the master switch off, unbuckled the safety harness, opened the door, and quickly exited the airplane. PERSONNEL INFORMATIONThe 38-year-old pilot held a Federal Aviation Administration (FAA) commercial pilot certificate with a single and multi-engine airplane rating. He held an FAA second-class medical certificate issued on March 8, 2017, with no limitations. He reported accumulating 5,215 hours total flight time and 1,738 hours of flight time in the same make and model as the accident airplane. The pilot also held an airframe and powerplant mechanic certificate. AIRCRAFT INFORMATIONN3045R was a full cantilever low-wing, all metal construction monoplane with serial No. H80-140, which was designed for agricultural flying. It has a maximum published gross weight of 10,500 lbs. The airplane was powered by a dual-spool turbopropeller 800-shaft horsepower GE H80-100 engine with serial No. 133001. The engine's gas generator section features a three-stage compressor that is comprised of two axial stages and one centrifugal stage, a reverse flow annular combustor, and a single stage turbine that drives the compressor. The power turbine section, counter rotating to the compressor's turbine, features a single-stage turbine and reduction gearbox (RGB) that drives the propeller. The engine was designed to operate with fuel being supplied to it by an electric fuel pump. However, the airplane's maintenance manual indicated the engine had a 100-hour limitation on operation without an electric fuel pump. According to the engine manufacturer, the engine build was completed on August 3, 2013, and the engine was fitted to the airplane on September 12, 2013. A pilot reported a very sensitive throttle while reducing power after takeoff where the torque will drop from 90% to 40% in a quick change even though the throttle is moved slowly and small amount. The squawk was troubleshot as a Fuel Control Unit (FCU) issue and on October 24, 2014, the FCU was replaced. Ground and flight tests were performed, and the airplane was returned to service. The airplane accumulated 494.34 hours of total time and 593 cycles since new at that time. A logbook endorsement dated June 12, 2015, indicated the airplane had a reported hot wire strike. The RGB bearings and FCU were replaced. The airplane accumulated 634.32 hours of total time and 967 cycles since new at that time. On April 18, 2016, the propeller governor was replaced at 1,069.87 hours of tachometer time. An issue with engine starting was reported and on August 25, 2016, the starting and limiting unit (SALM) was replaced. The engine was reported to start hot and on November 7, 2016, the FCU was changed. The airplane accumulated 1,629.27 hours of total time, 2,345 takeoffs, and 531 engine starts at that time. The pilot reported that the last inspection on the airplane was an annual inspection completed on February 20, 2017. The airplane accumulated 1,629.3 hours of total flight time at the time of the annual inspection and 1,737.6 hours of total flight time, 2,460 takeoffs, and 553 engine starts at the time of the accident. The pilot also stated that he installed a new electric main fuel pump T1800[9]-B8 serial No. 192737 on the airplane on August 4, 2016, and that the Hobbs meter indicated 1,428.6 hours. However, he did not provide a logbook endorsement of that main electric fuel pump. The pilot confirmed that main electric fuel pump accumulated about 309 hours of operation between the installation date and the accident date. The electric fuel pump manufacturer website describes the 18000 series pump as a slung vane, self-priming, high suction lift, and integral pressure relief valve pump with a built-in bypass valve, which is powered by a permanent magnet motor. The pump is designed for emergency fuel boost, priming injected engines, and primary fuel pump applications where aviation gasoline, jet fuels, and JP-8 is used. The H80 airplane was fitted with the Electronics International MVP-50T engine monitoring system. The MVP-50T consists of a multifunction glass panel engine monitoring and display system to display engine parameters, along with other data and warnings. The system performs monitoring tasks only. It does not perform any engine or aircraft system controlling functions. The MVP-50T system consists of the glass panel display unit (MVP-50T), the Electronic Data Converter (EDC-33T), and the transducer fuel signal conditioner. Each wing contains integral wing tanks (wet wing fuel tanks) just outboard of the fuselage. The left wing and right-wing fuel tanks are interconnected through a header tank. The published fuel system capacity is 228 gallons. The aircraft's fuel system is equipped with a 1/4-inch mesh finger strainer installed in the outlet fitting from the header tank. The fuel supply line to the engine is routed from the header tank, located in the fuselage, through a fuel shut off valve, an emergency electric driven fuel pump, and then directed to the main electric driven fuel pump. The fuel supply line exits the main pump and passes through a 10-micron nominal main fuel filter. The fuel line then goes through the fuel pressure sensor, which is located before the firewall. The fuel line is then passed through the forward firewall to the fuel flow meter, and then enters the engine's fuel pump. The emergency electric driven fuel pump is a backup system to provide continuous fuel pressure in case the main electric fuel pump fails. The main fuel pump and the emergency fuel pump are not to run simultaneously. The fuel tank vent system is designed to keep the fuel spillage to a minimum. The fuel tanks are vented through tubing connected at both the inboard and outboard ends of the individual fuel tanks to the centrally located vent system in the fuselage. Ram air enters a vent scoop, on the fuselage, under the left wing and pressurizes the vent system to maintain positive pressure on the fuel tanks. The vent system is provided with two quick drains, located on the fuselage under each wing, to drain any fuel that might happened to have migrated in the tanks outboard vent lines. Fuel quantity is displayed individually on the cockpit panel display. The airplane's flight manual (AFM) limitation section, in part, stated: FUEL PUMPS: Continuous simultaneous operation of both fuel pumps is prohibited due to high fuel pressure. The AFM advised pilots that an emergency hopper dump was available. The AFM, in part, stated: Should circumstances arise that require an emergency landing, the hopper should be dumped by moving the dump lever full forward. Forward pressure on the control stick or forward trim (or both) should be used to prevent excessive nose up pitching moment. Max speed for Hopper dump is 158 MPH. The AFM remedial action for an 'engine failure in-flight" in part, stated: Engine failure symptoms could include any or all of the following: a. Loud noises followed by heavy vibration and loss of power, smoke and/or flame. b. Rapid loss of power with unusual noises, vibration or sudden increase of ITT. c. Loss of power following a drop in oil pressure below redline or increase in oil temperature above redline or both. d. Loss of power following overspeed of gas generator (Ng). e. Engine explosion and flame & smoke. If it is clear that the engine has failed, proceed as follows: f. Hopper Dump DUMP LEVER FORWARD g. Propeller Lever FEATHERED h. Fuel Condition Lever CUT OFF i. Power Lever IDLE POSITION j. Fuel Valve Lever OFF k. Fuel Pump Switches OFF l. LAND AS SOON AS POSSIBLE The AFM additionally advises on operation with a "failure of automatic fuel scheduling." The remedial action for this failure, in part, stated: Normally the fuel scheduling is automatic, the engine power lever is positioned by the pilot and the fuel control schedules the fuel in a manner that allows smooth increases and decreases of power while not exceeding any engine limitations during acceleration or deceleration. In the event the automatic fuel scheduling fails, the engine will experience a "low side" failure, sometimes called a "roll back". The engine goes to minimum fuel flow, which is slightly below normal Ng idle speed. Fortunately the GE H-80 is equipped with an emergency governor which will allow the pilot to regain full control of the engine and safely return. While in Emergency Governor, all automatic fuel scheduling is lost and power is controlled by the fuel condition lever. Too rapid of movement of the fuel condition lever while in Emergency Governor can cause ITT exceedences, Ng speed exceedences, and compressor stalls. It's imperative that any power changes while in Emergency Governor be made smoothly and slowly allowing the engine to accelerate normally. Full power is available while in Emergency Governor. In the event automatic fuel scheduling is lost and the engine goes to minimum fuel flow. a. Raise the switch guard and place Emergency Governor Switch ON. b. Smoothly advance the ENGINE FUEL CONDITION LEVER until power is restored and a climb is established. c. LAND AS SOON AS PRACTICABLE. d. If power is not restored, LAND AS SOON AS POSSIBLE. After power is restored and you have climbed to a safe altitude, reduce the engine power lever to idle and continue the flight to a safe place to land using the Fuel Condition Lever as you would normally use the Engine Power Lever. The airplane's maintenance manual, in part, stated: POWER PLANT INSTRUMENTS This group [includes a] fuel pressure gauge. ... These readings are displayed on the MVP-50T Glass Panel Engine Monitor. ... MVP-50T FUEL FLOW The S2R-H80 aircraft is equipped with a MVP-50T glass panel display that reads fuel pressure and flow rate. The fuel flow transducer is installed in the fuel line between the engine's FCU and the fuel filter. ... ELECTRIC FUEL PUMPS The two electrical fuel pumps are installed in the fuel system. Two, two-position switches labeled MAIN ELECTRIC FUEL PUMP and EMERGENCY ELECTRIC FUEL PUMP on the start panel electrically control each pump. The emergency pump switch has a red guard cover. Both the pumps ... provide a fuel pressure of 12.5 to 34 PSI. These pumps provide positive fuel pressure continuously during starting and engine operation. ... TRACKING HOURS THE ENGINE HAS RUN WITHOUT INLET FUEL PRESSURE The S2R-H80 has two electric fuel pumps to provide fuel to the engine under the required pressure. The Main Fuel Pump is supposed to be operating whenever the engine is running. If it fails, as indicated on the MVP-50T by a low fuel pressure alarm, its switch is to be placed off and the Emergency Fuel Pump is to be turned on. This provides the fuel pressure the engine requires and would normally be only a matter of a minute or two without fuel pressure. Accumulating significant time on the engine without inlet fuel pressure would require either a dual fuel pump failure or a pilot who neglects to turn the Emergency Fuel Pump on when the Main Fuel Pump fails. … The MVP-50T records the engine operating parameters, which gives the mechanic a way to determine how long the engine has run without fuel pressure recently. METEOROLOGICAL INFORMATIONAt 1453, the recorded weather at the Salina Regional Airport, near Salina, Kansas, was, wind 320° at 4 knots, visibility 10 statute miles, sky condition clear, temperature 24° C, dew point 6° C, altimeter 30.02 inches of mercury. AIRPORT INFORMATIONN3045R was a full cantilever low-wing, all metal construction monoplane with serial No. H80-140, which was designed for agricultural flying. It has a maximum published gross weight of 10,500 lbs. The airplane was powered by a dual-spool turbopropeller 800-shaft horsepower GE H80-100 engine with serial No. 133001. The engine's gas generator section features a three-stage compressor that is comprised of two axial stages and one centrifugal stage, a reverse flow annular combustor, and a single stage turbine that drives the compressor. The power turbine section, counter rotating to the compressor's turbine, features a single-stage turbine and reduction gearbox (RGB) that drives the propeller. The engine was designed to operate with fuel being supplied to it by an electric fuel pump. However, the airplane's maintenance manual indicated the engine had a 100-hour limitation on operation without an electric fuel pump. According to the engine manufacturer, the engine build was completed on August 3, 2013, and the engine was fitted to the airplane on September 12, 2013. A pilot reported a very sensitive throttle while reducing power after takeoff where the torque will drop from 90% to 40% in a quick change even though the throttle is moved slowly and small amount. The squawk was troubleshot as a Fuel Control Unit (FCU) issue and on October 24, 2014, the FCU was replaced. Ground and flight tests were performed, and the airplane was returned to service. The airplane accumulated 494.34 hours of total time and 593 cycles since new at that time. A logbook endorsement dated June 12, 2015, indicated the airplane had a reported hot wire strike. The RGB bearings and FCU were replaced. The airplane accumulated 634.32 hours of total time and 967 cycles since new at that time. On April 18, 2016, the propeller governor was replaced at 1,069.87 hours of tachometer time. An issue with engine starting was reported and on August 25, 2016, the starting and limiting unit (SALM) was replaced. The engine was reported to start hot and on November 7, 2016, the FCU was changed. The airplane accumulated 1,629.27 hours of total time, 2,345 takeoffs, and 531 engine starts at that time. The pilot reported that the last inspection on the airplane was an annual inspection completed on February 20, 2017. The airplane accumulated 1,629.3 hours of total flight time at the time of the annual inspection and 1,737.6 hours of total flight time, 2,460 takeoffs, and 553 engine starts at the time of the accident. The pilot also stated that he installed a new electric main fuel pump T1800[9]-B8 serial No. 192737 on the airplane on August 4, 2016, and that the Hobbs meter indicated 1,428.6 hours. However, he did not provide a logbook endorsement of that main electric fuel pump. The pilot confirmed that main electric fuel pump accumulated about 309 hours of operation between the installation date and the accident date. The electri
A total loss of engine power during a low-altitude agricultural application flight for reasons that could not be determined during detailed examinations. Contributing to the accident was the pilot’s failure to follow the airplane manufacturer's emergency procedures to recover engine power, which resulted in a forced landing.
Source: NTSB Aviation Accident Database
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