Pratt And Whitney Pt6 Overhaul Manual
Pratt & Whitney is an American aerospace manufacturer with global service operations. Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially airlines) and military aviation.
PT6A engines are engineered for tomorrow to ensure you can go further today. Available in three series with increasing power levels and referred to as PT6A 'Small', 'Medium' and 'Large’ engine series, it is the most versatile turboprop engine family on the planet. The PT6A is the proven choice for demanding, high-cycle/high-power applications in single- and twin-engine aircraft for missions and applications of all kinds, including corporate, skydiving and agriculture, cargo, and amphibious missions.
. OWNeR WISDOm YOUR PT6A TURbOPROP.
Know your pt6A turboprop Congratulations on your acquisition of an aircraft powered by the Pratt & Whitney Canada Corp. (P&WC) dependable PT6A Turboprop Engine! Just like you, operators around the globe have made the PT6A engines their choice in the business and general aviation market –. Know your pt6A turboprop Should you require additional information related to: AOG / critical emergency services Technical / maintenance consultation Warranty Publications Field Service Representative (FSR) contact info Rental Engines Engine status in any P&WC Service Centre Eagle Service Plan (ESP ®. Know your pt6A turboprop Take note of your PT6A engine model and serial number. This will help us to coordinate 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.
DisclAimer Disclaimer The information contained herein has been set out in summary form and is provided for general reference purposes only and may be changed without prior notice. It should not be construed as creating any obligation on the part of Pratt & Whitney Canada Corp. While every care has been taken to avoid errors, Pratt &. nomenclAture ADAS Aircraft Data Acquisition System Aircraft Flight Manual Accessory Gearbox Aircraft On Ground Compressor Turbine ECTM Engine Condition Trend Monitoring ® ® EESP Extended Engine Service Policy Emergency Power Lever Eagle Service Plan ® ® Foreign Object Damage Field Service Representative Hot Section Inspection Interturbine Temperature Low Cycle Fatigue.
nomenclAture Propeller Speed PPSP Primary Parts Service Policy Power Lever Assembly Pilot’s Operating Handbook Power Turbine Rotations Per Minute Service Bulletin Shaft Horsepower Service Information Letter STOL Short Takeoff and Landing Time Between Overhaul Time Since Overhaul TTSN Total Time Since New TCSN Total Cycles Since New United Aircraft Corporation. Know your pt6A turboprop Initial Customer Support Presentation P&WC offers a three-part introduction to the company, engine maintenance and our aftermarket support logistics.
You have the option of scheduling a meeting at your convenience or we will be happy to send you an information kit with brochures and a copy of the presentation that you may review at your leisure. Know your pt6A turboprop Once we have been informed of a new PT6A engine delivery to an aircraft operator, a copy of the applicable new engine warranty will be sent to the new owner by the P&WC Warranty Administration department.
pt6A engine generAl PT6A Engine Overview Unmatched versatility, dependability and performance have made the PT6A engine the most thoroughly proven and popular turboprop engine family in the 500- to 1,700-shp class, covering a diverse range of applications across all aircraft markets. We continually invest in technology to make our engines the most environmentally friendly and to offer even greater value in the form of higher performance and digital engine control. moDulArity The design of the PT6A engine allows it to be split into two major parts called the power section assembly and the gas generator assembly. Only certain engine models are defined as being modular, which allows the interchange and tracking of each module. Three criteria must be met for the engine to be modular. ADvAntAges of the pt6A engine Design A number of advantages are derived from the design of the PT6A engine which have proven valuable in routine field operation. During an engine start, only the compressor section of the PT6A engine needs be rotated by the starter-generator.
By comparison, a fixed-shaft engine must spin all rotating components including the reduction gearbox and propeller during an engine start, resulting in a requirement for heavier starting systems. principles of operAtion The PT6A engine consists of two main sections, the gas generator section and the power section. The gas generator section compresses and delivers 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. Airflow Air is directed to a compressor consisting of three axial stages (Four axial stages on large PT6A engine models) and one centrifugal stage. Compressed air leaving the compressor passes through diffuser pipes which turn the flow 90 degrees, reduce its speed and direct the air into the combustion chamber. power trAin A shaft connects the power turbine to the two-stage planetary reduction gearbox.
The first stage reduction ring gear floats axially against a hydraulic torquemeter cylinder. The oil pressure in this cylinder is proportional to output torque which is displayed on the torque indicator in the cockpit. Bevel gears located forward of the second stage planetary gears drive the following accessories mounted on the forward reduction gearbox case:.
beArings Support of the main shafts in the PT6A engine is accomplished by a combination of ball and roller bearings. Ball bearings support axial and radial loading, while the roller bearings support only radial loads, allowing for thermal expansion. Propeller Shaft Power Turbine Compressor No. foD protection Inertial Separator The nacelle inlet of many aircraft models includes an inertial separator provided by the aircraft manufacturer to prevent heavy particles from entering the engine inlet. Most installations incorporate two moveable vanes, one upstream of the engine inlet and the other blocking the bypass duct. fuel system The fuel system is designed to deliver clean fuel to the engine at the pressure and flow that are necessary for all engine operating conditions. The airframe fuel system contains the necessary boost pumps, transfer pumps, selector/shutoff valves, strainers and filters required to supply fuel to the engine(s) and to manage the fuel load distribution in the airplane.
oil system The PT6A engine has a self-contained oil system 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. typicAl pt6A engine instrumentAtion Incorporated into the design of the PT6A engine are accurate and reliable torque and ITT measuring systems that give the pilot an accurate indication of the primary engine operating parameters. Torque Pressure is sensed by a torque pressure transducer mounted on the reduction gearbox, to indicate the torque being developed by the engine. controls Cockpit Powerplant Controls PT6A engine applications use the engine power management system and propeller beta control capability to obtain optimum airplane flight and ground handling capability. The powerplant functions are typically commanded from the cockpit by means of three control levers and push- pull cables.
controls Secondary control inputs located on the propeller governor include the beta valve and the fuel governor reset. These controls are used in conjunction with the propeller low blade angle feedback system and the engine propeller reversing control system for propeller beta control and reverse thrust control.
Propeller Overspeed Governor All PT6A turboprop installations are equipped with an airframe-supplied propeller overspeed governor. This unit has its own dedicated drive from the engine reduction gearbox and is intended to limit the propeller speed to a predetermined maximum value in the event of a malfunction of the primary propeller governor. emergency power lever Introduction The manual override function, when connected to the EPL, is intended for use during emergencies or closely monitored training only and must never be used during normal engine operation. This lever should only be used to modulate engine power to allow the pilot to continue flight to the nearest airport in the event of malfunction in the fuel control pneumatic system resulting in one of the following conditions: 1. scheDuleD mAintenAnce The following information is intended as an overview of maintenance practices. For a complete description please refer to the Engine Maintenance Manual (EMM).
Chapter 70-00-00 describes standard practices including servicing the engine oil system. Chapter 71-00-00 contains information on maintenance practices, including adjustment, test and cleaning. engine inspections Chapter 72-00-00, Table 601, of the EMM contains the minimum recommendations for regular inspections of the engine. There are two primary intervals, ROUTINE and MINOR. More precise intervals are used for specific components when required. ROUTINE inspections coincide with the daily or preflight airframe inspection. oil system inspection AnD servicing Oil Level Sightglass Some PT6A engine models are equipped with a sightglass to simplify the inspection of the engine oil level.
The sightglass has a centre green zone with red on each end. Engine operation is permitted with the oil level at any point in the green zone. oil system inspection AnD servicing Oil Temperature and Colour High oil temperature will accelerate the accumulation of carbon particles in the oil and the deterioration of oil additives. Oil colour will darken with usage and exposure to light. The rate of colour change is dependent upon the oil manufacturer’s formula. performAnce checK Over the life of the PT6A engine, the performance charts have evolved in name, style and function. Today, a variety of charts can be found.
They may be titled Power Assurance Check, Performance Check or Ground Power Check charts. The charts allow operators of PT6A engines to monitor the condition of their engines and the results of maintenance actions.
engine wAshing Atmospheric pollutants may contaminate the engine gas path, leading to a build up of deposits on airfoils, the initiation of corrosion, sulphidation or performance deterioration. These effects can be alleviated with engine washing.
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Internal engine washes are done while motoring the engine at 10-25% Ng speed for a thorough cleaning. engine wAshing External Engine Wash Used as an effective method of tracing oil leaks, as well as removing salt and other environmental contaminants from the engine external surfaces.
Wash fluid is drinking quality water, provided minimum standards are met. Wash Schedule When operating continuously in a salt laden environment (typically within 10 nautical miles from the sea and under 10,000 ft), it is recommended to perform compressor and compressor turbine desalination washes and.
engine wAshing Fairbanks Anchorage Seattle Montreal Denver New York Los Angeles Dallas Atlanta Houston Miami Havana Haiti Puerto Rico Mexico St. Domingo Corrosion Severity Zone Jamaica Mild Moderate Severe Figure 1 North American Corrosion Severity Map, extracted from FAA Advisory Circular 43-4A, 32 32. hot section inspection A Hot Section Inspection (HSI) is usually done halfway through the basic TBO interval 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.
overhAul The basic Time Between Overhaul (TBO) and Hot Section Inspection (HSI) interval is published in the appropriate Service Bulletin for each PT6A engine model. Under extreme conditions, maintenance action prior to the recommended overhaul life may be necessary. The TBO interval depends on the specified operation of the engine.
The interval can be escalated incrementally with the approval of your airworthiness authority, using an “on-condition”. cycle counting Certain rotating components of the engine have a limited life based upon the number of operating cycles they experience. These lives are quoted in the Rotating Component Lives Service Bulletin for each PT6A engine model. It is important to continuously record the number of operating cycles and partial cycles to track rotor lives. engine conDition trenD monitoring® ECTM is a computer software program sold by P&WC that assists in early ® detection of potential problems through continuous monitoring of engine operation. The advantage of using ECTM is a savings in troubleshooting ® time, reduced maintenance costs, the ability to schedule corrective action and an increased dispatch rate.
engine conDition trenD monitoring® Automatic trends can 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. recommenDeD pt6A engine power mAnAgement The PT6A engine power management system has been designed to give the pilot control of the powerplant thrust over the entire airplane flight and ground-operating envelope. It is a simple and reliable system, which fully compliments the inherent operating flexibility of a free turbine engine. recommenDeD pt6A engine power mAnAgement Rating Philosophy P&WC’s power rating philosophy is to ensure the maximum likelihood that your PT6A engine will deliver the power specified in the POH / AFM throughout its overhaul life.
To achieve this, all PT6A engine installations use torque as the primary power setting parameter. 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. recommenDeD pt6A engine power mAnAgement Power Ratings The take-off rating is the maximum power certified for takeoff and is time limited to five minutes. The maximum continuous rating is a certified power setting for in-flight emergency use only, typically for twin engine applications where one engine is inoperative. recommenDeD pt6A engine power mAnAgement Flat Rating At constant ITT, PT6A engine power reduces with both increasing ambient temperature 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 It is a general characteristic of aircraft that for a particular gross weight, the power required for take-off varies comparatively little with ambient conditions. PT6A engines are typically “flat rated” to allow for the maximum 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. recommenDeD pt6A engine power mAnAgement Power Settings All PT6A engine applications 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. recommenDeD pt6A engine power mAnAgement The power lever should be set to the position which produces the required torque.
Other engine parameters such as ITT 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. recommenDeD pt6A engine power mAnAgement Operating the engine beyond the recommended power settings specified in the POH / AFM for a prolonged period will result in accelerated margin deterioration due to hot section 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. P&WC Customer FIRST Centre Global Customer 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 09-1331.