Pratt & Whitney Canada PT6A Turboprop Instruction Manual Download Page 41 | Manualshive

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Performance Margins

“New Engine” production acceptance limits are designed to allow a
sufficient margin to carry the engine through a desired overhaul period. Any
engine overhauled and put back into service must meet similar standards.

However, with use, the engine performance margins will gradually
reduce characterized by an increase in ITT, Ng and/or fuel flow (Wf) while
maintaining POH / AFM specified power

TIME IN SERVICE - HRS

Maximum certified operating limit

Engine deteriorating

Deterioration margin

SPEED

AND TEMP

recommenDeD pt6A engine power mAnAgement

Performance Margins

“New Engine” production acceptance limits are designed to allow a
sufficient margin to carry the engine through a desired overhaul period. Any
engine overhauled and put back into service must meet similar standards.

However, with use, the engine performance margins will gradually
reduce characterized by an increase in ITT, Ng and/or fuel flow (Wf) while
maintaining POH / AFM specified power

TIME IN SERVICE - HRS

Maximum certified operating limit

Engine deteriorating

Deterioration margin

SPEED

AND TEMP

recommenDeD pt6A engine power mAnAgement

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Summary of Contents for PT6A Turboprop

Page 1: ...Key NEW OWNER WISDOm YOUR PT6A turboprop ...

Page 2: ...ise choice you are benefiting from 45 years and 300 million hours of in service experience resulting in unmatched reliability This handbook has been designed to give you a brief overview of the PT6A engine as well as some maintenance and power management recommendations Always refer to the Pilots Operating Handbook POH Aircraft Flight Manual AFM Engine Maintenance Manual EMM Service Bulletin s SB ...

Page 3: ...nes Engine status in any P WC Service Centre Eagle Service Plan ESP AOG Parts After Hours our Customer FIRST Centre is available 24 hours a day 7 days a week to assist you In Canada and the United States Tel 1 800 268 8000 International Tel International Access Code 8000 268 8000 Other Numbers Tel 450 647 8000 Fax 450 647 2888 Email cfirst pwc ca Visit our website at www pwc ca Know your pt6A turb...

Page 4: ... our support in a timely manner Engine Model Engine Serial Number Engine Logbook Each engine is supplied with a logbook s to record all maintenance actions as well as engine running times and cycles The logbook s must accompany the engine or module each time they are sent to an approved service or overhaul facility ...

Page 5: ......

Page 6: ...er resulting from the misuse misinterpretation analysis interpretation or application of any of the guidelines contained herein The information contained herein does not replace or supersede the information contained in the appropriate airframe or engine maintenance manuals or other official publications Always refer to the Pilot s Operating Handbooks POH Aircraft Flight Manuals AFM Engine Mainten...

Page 7: ...d CT Compressor Turbine ECTM Engine Condition Trend Monitoring EESP Extended Engine Service Policy EPL Emergency Power Lever ESP Eagle Service Plan FOD Foreign Object Damage FSR Field Service Representative HSI Hot Section Inspection ITT Interturbine Temperature LCF Low Cycle Fatigue MOR Manual Override Ng Gas Generator Speed ...

Page 8: ...k PT Power Turbine RPM Rotations Per Minute SB Service Bulletin SHP Shaft Horsepower SIL Service Information Letter STOL Short Takeoff and Landing TBO Time Between Overhaul TSO Time Since Overhaul TTSN Total Time Since New TCSN Total Cycles Since New UAC United Aircraft Corporation Wf Fuel Flow Rate Nomenclature ...

Page 9: ...tions may also be purchased The price list for commercial publications is available upon request by contacting Publications Customer Services For additional details on our Technical Publications including contact info please visit us at our website www pwc ca Warranty P WC prides itself in offering transferable warranty coverage that is amongst the best in the aerospace business The new engine war...

Page 10: ...cident which affects the engine e g prop strike hard landing you must inform P WC Warranty by filling out the form included in SIL GEN 039 This will ensure that your warranty policy is reinstated following the corrective maintenance actions Customer Portal Pratt Whitney Canada is committed to providing global support services that delights our customers The P WC Customer portal is just one of the ...

Page 11: ...and the other driving the propeller through a reduction gearbox The latter turbine is free or independent of the compressor turbine More recent higher powered models incorporate a two stage power turbine Over the years the PT6 engine has evolved and adapted to a multitude of uses The PT6A engine is the turboprop designation powering commuter corporate and utility aircraft aerobatic trainers agricu...

Page 12: ...the engine to be modular 1 Each major assembly is equipped with a data plate and a third data plate is located on the inlet case for the complete engine assembly 2 There is a logbook for each module 3 In the appropriate SB on service lives there will be an overhaul interval quoted for each module and the engine assembly On non modular PT6A engines the power section assembly can be removed and sent...

Page 13: ...l rotating components including the reduction gearbox and propeller during an engine start resulting in a requirement for heavier starting systems The PT6A engine free turbine design allows the propeller RPM to be reduced and the propeller feathered during ground operation without shutting down the engine This facilitates fast passenger loading and permits very quiet ground operation Propeller RPM...

Page 14: ...ivers air to the combustion chamber where it is mixed with fuel and ignited The resulting hot gases turn the compressor turbine which provides the power to run the compressor and the accessory gearbox located at the rear of the engine The hot gases continue on to the power turbine where the remaining energy is extracted to turn the propeller Np Nf T5 ITT Ng Wf FCU Tq ...

Page 15: ...s reached idle speed The expanding hot gases are directed first through the compressor turbine and then through the power turbine After passing through the power turbine the gases are exhausted through ports on each side of the engine Some engines are fitted with a single port exhaust The exhaust stubs fitted to the engine are normally directed to utilize the remaining energy of the gases in the f...

Page 16: ...uction gearbox case propeller governor or constant speed unit propeller overspeed governor tachometer generator The accessory gearbox mounted on the rear of the engine is used to drive the following engine accessories High pressure fuel pump Fuel control unit Oil scavenge and oil pressure pumps Space is also provided for aircraft manufacturer provided accessories such as the starter generator gas ...

Page 17: ... and radial loading while the roller bearings support only radial loads allowing for thermal expansion Propeller Shaft Power Turbine Compressor No 5 Roller No 3 Roller No 1 Ball No 6 Ball No 4 Ball No 2 Roller No 7 Roller Smaller reduction gearboxes do not utilize a No 7 bearing Bearings A 52 A 61 A 64 A 66 A 60 A 65 A 67 7 6 5 6 5 4 3 2 1 ...

Page 18: ... bypass duct vane is opened permitting maximum separating efficiency In some installations the vanes are fixed in the bypass mode As shown in the sketch air entering the engine inlet must turn sharply past the inlet vane shown in the lowered position Particles heavier than air are carried straight through by their own inertia into the bypass duct and dumped overboard The aft radial inlet design pr...

Page 19: ...c or a hydro mechanical system which meters the correct amount of fuel to the engine to maintain the gas generator speed selected by the pilot via the power control lever It also controls fuel flow scheduling during engine starting acceleration and deceleration The PT6A engine is approved for operation with all commercial jet fuels JP 4 JP 5 and for a maximum of 150 hours during any overhaul perio...

Page 20: ...with the exception of the oil cooler air duct and associated plumbing The oil level should be verified after engine shutdown and while the oil is still hot using either a dipstick or a sightglass For more information related to the oil system please refer to page 29 ...

Page 21: ...ction gearbox to indicate the torque being developed by the engine Torque is the primary parameter used to set power for takeoff and cruise operation for specified propeller speeds ITT is monitored to ensure that combustion gas temperature limits of the engine are not exceeded Two tachometer generators are installed on the engine one on the reduction gearbox monitors propeller speed Np and the oth...

Page 22: ...ome applications where certain powerplant functions are not required simplified systems using two or even one cockpit control lever may be used POWER RANGE BETA POWER LEVER CAM ASSY LOW IDLE PROPELLER LEVER PROPELLER GOVERNOR FUEL LEVER FEATHER REVERSE MIN POWER MIN RPM SHUT OFF MAX POWER TAXI RANGE MAX RPM HIGH IDLE Control Location Control Function Condition Fuel control unit or start control Fu...

Page 23: ...fferent propeller low pitch limit for ground operation Some installations utilize an airframe supplied propeller low pitch reset system actuated by means of a switch which senses the weight of the airplane on the main landing gear This functionality is integrated with the engine supplied propeller beta control system The system automatically sets the propeller low pitch limit to either the ground ...

Page 24: ...to a preset value This function has been utilized on applications where the normal power setting and monitoring procedures cannot be used such as military trainer aircraft which are intended to maintain the maximum operational similarity to high performance jet aircraft Other applications with substantially flat rated PT6A engines utilize an overtorque limiter to prevent inadvertent excessive powe...

Page 25: ...he function of the PLA and is not to be used as an optional means of controlling the engine The EPL overrides all automatic fuel control features and acts directly on the fuel valve to directly modulate the fuel flow to the engine Rapid movements of this lever should not be made for any reason whatsoever EPL sensitivity increases with altitude and above 5000 ft extreme care should be exercised Ple...

Page 26: ...0 00 contains information on maintenance practices including adjustment test and cleaning Chapter 72 00 00 outlines inspection criteria for various sections of the engine The inspection procedures are considered a normal function of the operating organization and are intended as a guide for minimum inspection and maintenance requirements The aircraft manufacturer may have additional requirements o...

Page 27: ...s should be subjected to additional inspections for corrosion and compressor erosion The engine maintenance manual quotes recommended intervals which the operator can adjust based upon operating experience Typical maintenance actions include Engine washing Compressor Desalination Wash Compressor Turbine Desalination Wash Compressor Performance Recovery Wash Foreign Object Damage FOD inspection of ...

Page 28: ...every shutdown Oil Replenishment P WC recommends that the engine not be filled over the MAX COLD level on the oil level dipstick This corresponds with the centre of the green band on the oil level sightglass A high oil level may result in an increase in either the oil consumption rate or the amount of oil mist passing through the engine oil breather Each engine will seek its own normal operating o...

Page 29: ...proximately litre 17 oz of residual oil Chip detectors should be checked regularly for continuity and any foreign material If the aircraft is equipped with a cockpit indication of the chip detector the whole system should also be checked regularly Refer to the applicable maintenance manuals for inspection intervals Oil Filter Debris Analysis The oil filter must be changed or cleaned at scheduled i...

Page 30: ...y the powerplant as a whole not just the engine The effects of poor nacelle seals bleed air leaks accessory drive power and instrumentation errors are all reflected in the recorded data Do not use the chart to reject engines from service Engines may remain in service provided that no operating limits are exceeded at the certified powers P WC recommends that troubleshooting and a flight test be don...

Page 31: ... cause sulphidation a reaction between the salt and sulphur from the fuel This wash must be done immediately following a compressor desalination or performance recovery wash as contaminants will be transferred from the compressor to the hot section during a compressor desalination or performance recovery wash Wash fluid is drinking quality water provided minimum standards are met Water is injected...

Page 32: ... initiating overnight For occasionally salt laden operation weekly desalination washes and external washes are recommended Performance recovery washes are only recommended when a noticeable performance shift is recorded In all cases engine washing frequency should be based on operator experience and regular inspections of engine components to check for initiation of corrosion Refer to P WC SIL PT6...

Page 33: ...everity Zone Moderate Severe Mexico Seattle Fairbanks Montreal New York Atlanta Dallas Denver Houston Havana Miami Haiti Puerto Rico St Domingo Jamaica Anchorage Figure 1 North American Corrosion Severity Map extracted from FAA Advisory Circular 43 4A ...

Page 34: ...val or when performance loss dictates This involves splitting the engine between the compressor and power turbines at C Flange Since it is generally not necessary to remove the engine from the aircraft during an HSI the inspection procedure is both simple and fast Hot Section Inspection ...

Page 35: ...he engine The interval can be escalated incrementally with the approval of your airworthiness authority using an on condition or a sampling program The current TBO escalation is limited at 8 000 hours for single engine aircraft and 10 000 hr to 12 500 hr for twin engine aircraft depending on the application TBO escalation recommendations take into account the average effect of flight duration time...

Page 36: ...f operating cycles and partial cycles to track rotor lives Rotor components not supported by proper documentation are to be removed from service Prior to engine servicing the total cycles and all flights and starts must be recorded in the appropriate engine logbook At engine overhaul a calculation will be made of the remaining service life for each rotating component This calculation is based upon...

Page 37: ...s the quality of the data provided On board data recording Altair Avionics markets a PT6A engine mounted data recording system called TrendCheck Plus and the Aircraft Data Acquisition System ADAS an airframe mounted engine monitor for a wide variety of PT6A engine applications These monitors enhance safety and reduce direct operating costs through sophisticated aircraft exceedance monitoring and a...

Page 38: ...an be defined or pilot initiated samples can be captured by the push of a button Data stored in the Altair Internet based TurbineTracker system can be used directly with the ECTM program Additional information on these products can be found at www altair aero ...

Page 39: ...aft Manufacturer a mission profile is established for every PT6A engine application This mission is used to analyze and establish engine component lives and durability factors such as Low Cycle Fatigue LCF Creep Oxidation and Vibration Using this data and taking into consideration airframe influences such as bleed extraction accessory loading and inlet efficiency the power setting information is e...

Page 40: ...e POH AFM contains power setting information which must be used to determine the torque setting for all ratings which vary according to altitude ambient temperature and aircraft weight This is important because the P WC rating philosophy is based on the engine being operated per the POH AFM and maintained in accordance with the EMM AMM including all applicable periodic inspection recommendations b...

Page 41: ...uled and put back into service must meet similar standards However with use the engine performance margins will gradually reduce characterized by an increase in ITT Ng and or fuel flow Wf while maintaining POH AFM specified power TIME IN SERVICE HRS Maximum certified operating limit Engine deteriorating Deterioration margin SPEED AND TEMP Recommended PT6A Engine Power Management ...

Page 42: ...rating is a certified power setting for in flight emergency use only typically for twin engine applications where one engine is inoperative Maximum climb and maximum cruise ratings are the maximum powers approved by P WC for climb and cruise operation Recommended PT6A Engine Power Management TAKE OFF POWER MAX CONTINUOUS MAX CLIMB MAX CRUISE ...

Page 43: ...and altitude This represents the thermal capacity of the engine or thermal rating and is how the engine would perform without the mechanical limitations of the reduction gearbox Recommended PT6A Engine Power Management TAKE OFF AMBIENT TEMPERATURE AND ALTITUDE POWER MAX CONTINUOUS MAX CLIMB MAX CRUISE ...

Page 44: ...um possible take off power required by the aircraft over a wide range of ambient temperatures without having to work the engine harder than is necessary at any time The flat rated power is available up to the thermal capability of the engine specified as an ambient temperature and altitude Recommended PT6A Engine Power Management Ambient Temperature and Altitude POWER Take off Max Continuous Max C...

Page 45: ...pplications use engine output torque as the primary power setting parameter The POH AFM contains power setting information which must be used to determine the correct torque settings to achieve take off and cruise in accordance with altitude ambient temperature and aircraft weight ...

Page 46: ...TT and Ng are monitored only to verify that they are within acceptable limits Operating the engine in accordance with the POH AFM by using torque as the primary power setting parameter will achieve optimum reliability and durability while minimizing operating costs 0 ITT or NG Maximum fully deteriorated limit POWER Torque set as per POH LIFE 100 MARGIN REDUCING ...

Page 47: ...ion component distress and will affect engine reliability and durability This effect is cumulative and will lead to the engine prematurely reaching an operating limit usually ITT before the recommended power is produced Refer to P WC SIL PT6A 125 for additional information LIFE 100 0 POWER ITT or NG Maximum fully deteriorated limit POWER SET AT MAX ITT LIMIT Normal torque as per POH Actual torque ...

Page 48: ...mer Service 24 hours a day 7 days a week In Canada and the United States Tel 1 800 268 8000 International Tel International Access Code 8000 268 8000 Other Numbers Tel 450 647 8000 Fax 450 647 2888 Email cfirst pwc ca Visit our website at www pwc ca ...

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