THEORY AND MAINTENANCE
Contents
1. 13 What type inspection must be meee after sudden stoppage of an engine dye to striking and object The propeller drive shaft must be checked for misalignment and the Propeller checked for track 14 What isthe purpose of ene erami pamper wire in aircraft engines me wR i Dampers are used to av rcomi faites Which cause dienction of the Crankshaft and torsional vibration These forces are generated by the power implils s of the Pist kst w vibrations are reduced by placing floating dampers we ts in particularly ini sihgl throw type crankshaft oH 15 H w w ld yot makea runout check ona cfankshalt that is sti W iistaled int ie engine Remove the propeller from the shaft and attach a dial indigato gage to the front of the crankcase Adjust the position of the gag n edle so that ii is touching the shaft Turn the engine through With the starter ae note any changes i in th gage r ading 16 What is detonation Normal bambusa is when the fuel air mixture burns ata a uniform rate across the combustion chamber The temperature and pressure within tHe eylinder rises ata normal rate as the mixture bu s All fuels have critical limits of temperature and compression and beyond this limit they will ignite spontaneously and burn with explosive violence This instantaneous explosive burning of the last portion of the charge is Called detonation ei 12. g A fixed pitch propeler a What Is the purpose of the metal tipping on th cot o s r EE paie Sorri Er s to protect the propeller from damage caused by icles in the air during landing taxiing and takeoff ean o What is the process of determining the positions Sethe tip St EHS propoller blades relative to each other BLADE 9 TRACKING 6 What tool Stised t determing propeller blade argh WE 1 A universal propeller protractor 2 7 What are the aerodynamic forces and loads acung BLY Se ty rr A rotating propell r i is acted upon by centrift 8 What is the meaning of propell r blade back and face The cambered or curved side of the propeller blade is called the blade back This is the side of the blade that faces away from the engine The flat side of the propeller blade is known as the blade face This side of the blade faces the engine 9 What should be used to clean aluminum and steel propeller blades and hubs _ They should be washed with a sultable cleahing solvent using a brush or cloth 10 What positions are used on a balance stand to check a two bladed propeller for static balance First the vertical position and then a horizontal position 11 When centrifugal force acts on the countenwelgns of a hydraulic counterweight propeler it it tends to rotate the blades in which direction m Centrifugal forc tends to incregse the blade pitch l 12 Why
3. paardeen oe aR d Rnd om i a melt 14 What are the functions of engine Ql In a_reciprocating engine In addition to lubrication oil cools various parts of the engine helps to seal the combustion chamber by providing a film between the cylinder walls and the rings and aids in cleaning the engine by carrying engine residues to the oll filter 15 What is the weight of alrctaft erigine ol Approximately i 4 Roynds pery 8 gallon 16 What is the Purpose of an oil ilution system The oil dilution ERTA thins the oil by introducing fuel iia the lubrication system which makes cold weather starting easier ae a 1 Spee ie aircraft enone ang check the oil cooler for proper operation 2 Inspect an so caoler for leaks after engine runap 3 Perform an engine oll pret adjustment i 4 Drain an oil tank 5 Service an oil tank 6 Locate an danin each of the oil yem components 7 Inspect oll lines for leaks 8 Using reference material preall 4 an Sione 9 Using reference material list possible causes of low and High oil temperatiire Malfunctions 10 Indicate the direction of oil flow op a drawing of at oll systent 11 Examine an oil filter or screen and identify any foreign materiel 12 Determine the proper oil for three different climatic temperature conditions t3 Using aircraft reference data select the approved oil for three engines 14 Remove clean and reinstall a scav
4. THEORY AND MAINTENANCE RECIPROCATING ENGINES ORAL How are conventional reciprocating engines classified They are classified according to cylinder arrangement with respect to the crankshaft in line V type radial and opposed or according to method of cooling liquid cooled or air cooled What are the different types of piston rings Compression rings oil contro rings and scraper rings What is the purpose of the oil contro rings They are used to contro the thickness of the oil film on the cylinder wails What may be the result of installing piston rings incorrectly Excessive oll consumption ATE T What type of piston rods are Commonly young in radial engines Moor A master and artigulating rod assembly What type bearings are in genera use in reciprocating engines Plain bearings which are generally used for crankshaft cam ring camshaft connecting rods and accessory drive shaft bearings Roller bearings which are used primarily as crankshaft main bearings but have other applications as well Ball bearings which are used for supercharger impeller shaft bearings rocker arm bearings in some engines and as propeller thrust bearings What is the indication of valve blowby Valve blowby is indicated by a hissing or whistle when pulling the propeller through prior to starting the engine A cylinder compression check should be made to identify the faulty cylinder What is the purpose of using more than
5. bric tion arid affects Combustion 11 Describe an augmentor system 0 0 t 0 555 a 0 T Augmentors consist of two pairs Of tubes fitrining from the engine compartment to the rear of the nacelle The exhaust gas collector feeds exhaust gases into the inner augmentor tubes Air that has passed over th engin is f d into the outer tubes wliere it is heated by the exhaust tubes and then expelled to mix with the exhaust gases The heating of the air causes it to form a high temperature lowpfesstife j tsike xtiauist which draws additiahal oolirig air overthe engine The heated air is sometimes used for cabin heating defrosting and aniicicing 7 te et it if ii te Mir GE Wits f tae is R et a L E et ar tirin VAN TRTAT REF Sa 1 12 What is the source of air that is directed to turbine engine bearings for codling it is bleed air from the compressor section of the engine Le mE Remar a 88 13 What is the purpose of insulation blankets on the exhaust duct of a turbine engine To reduce the temperature of the structure in the vicinity of the exhaust duct or afterburner and to eliminate the possibility of fuel or oil coming into contact with the hot parts of the engine 14 What types of material are used to make insulation blankets for turbine engines They are made of stainless steel with layers of aluminum foil fiber glass and silver foil 15 What areas of a turbine engine are
6. What category is a turbine engine driven gear type pump Constant displacement What type fuel pump can be made to vary y the fig flow at any yebead A variable displacement pump What part of a gas turbine engine fuel systern Is vey ac io to the formation of ice The fuel Titer i l ee ee How is the engine fuel system protected fr m iee formation 7 By the use of fuel heaters Why is a micron fuel filtet pfovitied with a bypass vaias i a neeeseary safety factor Because the small openings in this type filter iiiak every susceptible to lbgging xa evi poia Sash on ie whey ENGINE E FUELS SYSTEMS PROJECTS st moe ode atthe sat o A Riria as Using reference material adjust the output pressure on an engine driven fuel pump to within limits Using reference material remove clean and t eplace an ehgltie fuel Strainer Inspect a main fuel filter assembly by pressurizing the fuel system_and observing for fuel leaks in the filter area ea Wek eee pen dees Ni Sines FR we leh ay GG ted ve Remove and reinstall an engine driven fue pump using reference material as a guide 85 identify the components of an engine driven fuel pump Remove and reinstall an electrically driven boost pump Identify the components of an electrically driven boost pump Correctly adjust fuel pump pressure to the limits prescribed in reference material inspect fuel lines for fuel
7. What other engine characteristics are designed to aid in engine cooling besides cooling fins The engine cowling and baffles are designed to force air over the cylinder cooling fins 4 Why is the open and close adjustment during installation of cowl flaps important For each engine installation the cowl flaps are set for tolerances that will permit them to open and close the correct amoun ntfolkeep the cylinder head temperate within allowable limits 5 What should be done to cylinders when too much of the cooling fin area is broken off The cylinder shouid be replaced because it cannot cool properly and a hotspot will develop 6 When should cow flaps be kept i in the fully open position Normally during all ground operations 7 What publication should be referred to before reprofiling cylinder cooling fi fi ns The manufacturer S service or overhaul manna should be used to obtain the allowable limits 8 What power sources are ied to operate the cowl naps Cowl flaps may be operated by electrical power hydraulic power or manually 9 What is the purpose of blast tubes that are built into the baffles ona recinropaninag engine X To direct Jets of cooling air onto the rear SOAR puge elbows of each cylinder to prevent overheating of the ignition leads 10 What are the main reasons that excessive heat in reciprocating sribine is undesirable R Excessive heat shortens the if of the engine parts impalrs I
8. What type of exhaust system is generally used on low powered non supercharged engines The short open stack system 4 What type of exhaust system Is used on turbocharged engines The exhaust collector system 5 Which type of exhaust system creates a higher exhaust back pressure The collector system 6 What is the purpose of a reciprocating engine exhaust system To dispose of the high temperature noxious gases that are discharged by the engine NO What happens when lead zinc or galvanized marks are made on an exhaust system The mark is absorbed by the metal when it is heated and causes a change in the molecular structure of the metal 8 What type of visual indication can usually be seen in the area of an Gamalis leak Exhaust leaks usually leave flat gray or sooty black streaks on the pipes iri the area of the leak 9 How are ceramic coated exhaust stacks cleaned By degreasing only 10 What is the usual cause of momet and heat exchanger failures They are usually caused by thermal and yibration Saking or ruptures in areas of stress concentration Where are exhaust manifold ant stack eal most likely to occur These failures usually occur at Welded or clamped points in the system l 12 What isa common cause ack the waste gate unit malfunctioning in a turbochatger system hoki pi TF Tost common calles of waste gate maltunetioning is carbon buildup causing the wasige gate valve to
9. a turbine engine Inspect combustion liners and determine their return to service quality Check the axlal and radial clearance of turbine blades and determine If clearance Is within limits 70 10 1i 12 13 14 15 46 17 18 Inspect inlet guide vanes and compressor blades for damage and determine If engine Is return to service quality Identify and list different types of damage on turbine blades Remove and reinstall compressor or turbine blades Identify damage to nozzle guide vanes Adjust turbine idle rpm to within limits required by reference material Using reference material paion a hot start inspection Using reference material perform an overspeed inspection Match a list of turbine indication malfunctions with the possible cause of each malfunction Labe the direction of airflow on a drawing of a turbine engine and indicate the changes in air pressure between engine sections ENGINE INSPECTION ORAL What steps must be taken in order to prepare an aircraft for a 100 hour or annual inspection Remove or open all necessary inspection plates access doors fairing and cowling Then thoroughly clean the aircraft and the engine What may be used as a guide for a 100 hour inspection on an aircraft engine FAR Part 43 Appendix D What additiona inspection must be performed if the cylinder compression is weak You must make an internal cylinder inspection for improper internal tolerances Wh
10. determines the mass of air that is used by a jet engine The factors that affect density are the temperature and pressure of the air If density increases thrust increases and vice versa An increase in air temperature entering an engine will cause a decrease in density and thrust An increase in air pressure entering the engine will cause an increase in density and thrust With a given throttle setting engine thrust will vary if the temperature or pressure of the air entering the engine changes What are the two most common types of thrust reversers The mechanical blockage type and the aerodynamic blockage type What is a split compressor system iti a turbine engine The split Golnpressor system requires two concentric shafts joining the turbine stages to their resp ctive compressors What is one method of relieving th rmal stress on a turbine disk One means Is to bleed cooling air back onto the face of the disk What may be the indications if a turbojet engine is out of trim The enging has high exhaust gas temp rature EEN at target engine pressure ratio EPR for lt tak off TURBINE ENGINES PROJECTS Remove and install a combustion chamber case and liner Adjust turbine engine fue control Properly start operate and shutdown a turbine engine Identify turbine blades Identify the major components of a turbine engine Identify different types of compressors Correctly remove and reinstall a fuel nozzle In
11. one spring for valve closing if only one spring is used to close the valve It will vibrate or surge at certain speeds To eliminate this difficulty two or more springs one inside the other are installed on each valve Each spring will vibrate at a different engine speed and the spring surge vibrations will be dampened Two or more springs also reduce the danger of weakness and possible failure by breakage due to heat and metal fatigue What is the purpose of valve overlap Valve overlap permits better volumetric efficiency and lowers the cylinder operating temperatures LOS PRESSURE alee S Oen Presse FRESIRE 66 10 Describe the inspection you would give the valve springs during engine overhaul They should be cleaned thoroughly and then visually inspected for evegnce of pverheating cracks broken ends and for compression strength 11 What i is the purpose of using valves with souin filled stems Some intake ahd bahaust Valve Stems are hollow and partially fi filled with metallic sodium Sodium Is used because itis an excellent heat conductor The sodium melts at about 208 F and the movement of the valves circulates the liquid sodium which enables Itto carry the heat from the valve head to the stem where it is dissipated through the valve guide to the cylinder nar aw cooling fins 12 What causes engine sudden st bpage i Striking an object or engine selzure due to mema jamage sie
12. stick in the closed position E 13 What factors are affected if the habeas of the exhaust nozzle of a turbine engine is changed Visas ns Te i The size of the exhaust noe Shoes both the engine peneananes and the exhaust gas H temperature f 14 What are the probes in a turbine exhaust tail pipe used for gt l They are used to measure exhaust gas muerte EST ag s4 90 ENGINE EXHAUST SYSTEMS PROJECTS eh Detect and repair an exhaust system leak 2 Perform a heat exchanger collector tube leak test 3 Inspect an exhaust heat exchanger and list any cracks or damage 4 Remove and reinstall an exhaust manifold heat exchanger collector tube 5 Remove and reinstall exhaust ducts 6 Clean ceramic coated exhaust pipes 7 Identify exhaust system components Check a turbine engine thrust reverser Systa for proper oper tion gt eet Inspect a turbine engine exhaust nozzle enema e g eaog Determine if three exhaust system components with damage are repairable 11 Inspect an xbaust system internal baffles or iffuset st ny damage found 42 Determine the cause of a malfunction in a thrust reverser system TR RE LTR A er EEE v aard Py What is the purpose of a propeller To create thrust and either pull or push the airplarie throug air 2 What are the two classifications of propellers The tractor type and the pune oen x
13. the proper size Jug for the alternating rating A 11 Correctly flash the field of a DC onerata 12 Repair the lacing cord on a wire bundle using single cord lacing 13 Fabricate and instal an electrical bonding jumper t4 Solder splice three different sizes of wire 15 Fabricate a solderless electrical terminal 16 Using reference material determine if a starter generator Is authorized for installation on a specific engine 17 Using reference material select the proper size wire for several electrical system components 18 Use a voltmeter to locate an open in a generator field circuit 77 10 11 12 13 What would ee an indication of blocked oil goar passages LUBRICATION SYSTEMS ORAL What is the primary purpose of lubricant in m aircraft engine To reduce friction between moving parts l What is the most important property that aircraft reciprocating engine oll must possess Viscosity What factors must be considered in determining the proper grade of oil to use in a specific engine The operating load rotational speeds and operating temperatures are the most important factors to be considered What is the purpose of ihe oll flow control valve The oil flow control aE located on the oil cooler regulates the flow of oil either into of around the a cooler What are the main oil contaminants _ They are gasoline moisture acids ditt carbon and nietallic particles From what lo
14. the purpose of an engine driven fuel pump The engine driven fue pump st d iier coftiiuous supply of fuel at the proper pressure at all times during engine operation What type fuel pump is genetally used with large r ciprocating engines A positive displacement rotaryane type pump 84 10 What happens to the excess fuel not required by the engine in a constant displacement pump The pressure relief valve opens and the fuel Is routed back to the inlet dis of the pump What is the most common type of fuel boost pump The electrically driven centrifugal type pump What is the purpose of the bypass valve in the engine driven fuel pump The bypass valve provides a path around the pump vanes for starting the engine and to allow fuel to bypass the pump in case of pump failure What is the purpose of using boost pumps In a fuel system Electric boost pumps are used to supply fuel to a pressure carburetor during engine starting and in case of engine driven pump failure However a main function of a boost pump is to keep the pressure on the suction side of the engine driven pump from becoming low enough to permit the fuel to boil when operating at high altitudes What are the three general causes of vapor lock They are low fuel pressure high fuel lemperaules and excessive fuel turbulence Turbine engine fuel pumps may be divided into whit Wo distinct system categories Constant displacement and variable aspacement
15. 7 During valve clearance adjustment onan Re 2800 engine why must Your depress certain valves other than the ones being sees The valves must be depressed uiiloaitedy in ender to remove the spring ienien fr mi the side positions on the cam and thus permit the cam to slide away from the valves to be adjusted until it contacts the cam bearing This prevents cam shift from Introducing errors in the clearance settings 18 What can be learned about the condition of an engine by studying the results of a compression check From the cylinder compression check you can determine if the waves piston rings and pistons are adequately sealing the combustion chamber 67 19 How can a cold cylinder be located on a double row radial engine A cold cylinder check can be made with a cold cylinder indicator sometimes called a magic wand to locate any cylinder that has a temperature lower than the normal operating temperature of the other eyinders 20 What Instrument can be used to check a cylinder bore for out of roundness A cylinder bore can be checked with dial indicator a telescopic gage and micrometer or an inside micrometer RECIPROCATING ENGINES PROJECTS Check piston rings for correct end and side Ceatance l Check valve stems for stretch emg a contour gage or micrometer Repair a Scored alufninum piston f Locate and inspect engin mounts in accordance with reference material Adjust engine o p
16. NE ENGINES ORAL What are the major components of a typical gas turbine engine A typical gas turbine engine consists of an alr inlet a compression section a combustion section a turbine section an exhaust section and the accessory section What are the two principal types of compressors used in turbojet aircraft The two most common compressors in use today are the centrifugal flow and the axial flow types What are three types of combustion chamber systems They are the can type the can annular type and the annular type What is the purpose of the interconnector tubes between can type combustion chambers To spread the flame to the combustion chambers that are not equipped with igniter plugs during engine starting What prevents burning of the liner walls in can type combustion chambers Louvers are provided along the axial span of the liners to direct a cooling layer of air along the inside wall of the liner What types of damage may be found when inspecting compressor blades Dents scratches gouges galling burns burrs pitting and cracks What is the location and function of the diffuser section in a turbine engine The diffuser is the divergent section of the engine located between the compressor section and the burner cans Its function is to change the high velocity compressor discharge air to static pressure Where are stress rupture cracks most likely to occur on turbine blades They usually appear as small hai
17. buretor The AMC contains a sealed bellows that expands or contracts with changes in atmospheric pressure The movement of the bellow op rates a tapered needle that controls the impact air pressure into the A chamber of the carburator In what position do you place the mbture control ofa pressure injection carburetor to stop the engine In the idle cutoff position What rpm indication should result when the mixtur cohtrol is placed in the idl cutoff position when the idle mixture is set correctly There should bea alight increase in rpm followed by a rapid drop of rpm to zero What Is the purpose of filling a pressure injection carburetor full of fuel and allowing it to soak for a period of about eight hours prior to installation This is done is order to soften the diaphragms and make thearn as pliable as they were waen the carburetor was originally calibrated FUEL METERING SYSTEMS PROJECTS Inspect a turbine engine fue control unit for fuel leaks security and missing safety wire Trim a turbine engine fue control as prescribed by reference material Check and adjust the float level of a float type carburetor to within prescribed limits 83 Fi SE ee S p 10 1i 12 13 14 15 16 17 18 Repair a leaking float Using reference material adjust the idle speed on a float type carburetor Using reference material adjust the idle mixture on a float type carburetor Using reference
18. cation on a r ciprocating engine is the oil teiiperature Usually taken eg Ina dry sump lubrication system the oil temperature bulb is located anywhere in the oil inlet line between the oil tank ahd the ngine Wet sump systems have th teriperatur bulb located where it senses the temperature after the oil passes through the oil cooler In ither system the bulb is located where it measures oil tampefattire before it eriters the hot sections of the engine What do metallic pales On an oil s rben indicate E Metallic particles may be an indication of memng failure of the engine What could cause oil foaming Foaming can Be caused by diluted oil contaminated oll or the oil level too high x Ee ae re a High oil temperature What woua an indication of an aeiio oil supply K Low oil pressure and high ol temperature ne What type of oitis used in turbine engine lubrication systems Specially developed synthetic oils What are tivo types oF oil coolers us d in turbine hgihe lubrication systems The air cooled oil cooler and the fuel cooled oil cooler are the two basic types in general use Ri What is the meaning of oll flash point Fire point Oil flash point i is that temperature at whieh the oil will ii begin to ie off anisi vapors The fire point is that temperature at which there are sufficient vapors to support a flame 78 a K a r Bk T i ia i Si
19. cooled by the secondary air passing through the engine The combustion chambers and the turbines ENGINE COOLING SYSTEMS PROJECTS 1 Install cylinder head baffles k 2 Reprofile a damaged cylinder cooling fin Repair damaged cylinder head baffles Troubleshoot a cowl flap system to determine the cause of a malfunction Check cowl flap trave and determine if the open and closed positions are within limits Inspect cylinder cooling fins for damage and determine if the damage is repairable Locate and point out all the parts of an augmenter cooling system inspect an augmenter cooling system and determine if it is return to service quality Inspect a rotorcraft engine cooling fan for damage Identify a rotorcraft engine cooling fan and associated components Using reference material repair a turbine engine insulation blanket gt On a drawing of a turbine engine draw in the cooling air flow path and list the units being cooled On a drawing of a turbine engine point out the areas where an insulation blanket is required ENGINE EXHAUST SYSTEMS ORAL What are two types of reciprocating engine exhaust systems The short stack system and the collector system What are the possible hazards of exhaust system failure Depending on the location and type of exhaust system failure it can result in carbon monoxide poisoning of the crew and passengers partial or complete loss of engine power and an aircraft fire uss 89 3
20. do you put the blades of a counterweight propeller into high pitch before stopping the engine This type propeller has a movable cylinder that Slides over the propeller piston In the low pitch position the cylind r i outb ard and the pistoi is xposed to thie open alr but in the high pitch position the cylinder moves Inboard and covers the propeller piston In this position the piston is protected from dit and moisture in the alr This is parilomany liportnt H if the paa anona will not be operated for several days ce lets 13 Why are cones installed on splined shafts with me propenar The cones center the propeller on the shaft as 5 they are forced toward each other by the tightening of the retaining nut _ 14 How is feathering ac omplished ori a constant speed counterweight propeller gt Releasing governor oil pressure allows the counterweights and feathering spring to move the blades to the feathered position 15 What type ice control systems aie used for propellers Either fluid or electrical deicing syetems are used for deicing propellers 46 What is the purpose of a slinger ring on some propeller installations Propeller deicing fluid is ejected from a stationary nozzle on the engine late a scoop Saiched to the rear of the propeller assembly This U shaped charinel is called the slinger ring The fiuid under pressure of centrifugal force is transferred through a nozzle t
21. e fire protection systems g Xb They are overheat detectors rate of temperature rise detectors and flame detectors 2 When using a thermocouple type fire detector system what happens if the engine overheats slowly A thermocouple depends on the rate of temperature rise and will not give a warning if the engine slowly overheats or a short circuit develops 3 Describe the operation of a Kidde continuous loop fire detector system The Kidde continuous Joop system has two wires imbedded in a special ceramic core within an Incon l tube One wire acts as an internal ground and the other wire is a hot lead that provides a current when the ceramic core material changes its resistance with a rise in a 4 Where does a thermocouple fire detector system get its electrical power to operate Be The thermocouple produces power to close a relay and power from the aircraft electrical system flows through the relay to the warning light 5 Describe a thermal switch fire detector system ae Thermal switch systems have one or more lights that are energized by the aircraft electrical xP system when a heat sonsitive thermal switch clases the circuit at a specific temperature 6 How are thermal gwhehes le tric lly hh ct d in the circuit The thermal switches are connected in parallel with each other but in se es with the Waming light A temperature rise in any one section of the circuit will cause a thermal switch to close and complet
22. e the circuit to indicate a fire or overheat condition 7 What is the most common cause of a false fire warning in a continuous loop detector system The most common cause of false warnings is dents kinks or crushed sensing element causing an internal wire to short to the roune wire or outer tubing 8 What two methods are tis d to discharge h ire e extinguishing agents Mechanical ahd electrical 9 What method is used to sates the fre extinguishing agent ina typical 1 turbine engine fire protection system 540 m wt One common method is to equip the fire aidu contain rs with discharge valves that are operated by lectrically discharged Gattridges The discharge plug Is sealed with a breakable disk that is ruptured by the explosive cartridge and th eoritents of the boitle is dischafged into the engine area 10 What method is used to determine proper fire extinguisher container pressure Check the container gage to determine if the pressure is between the prescribed minimum and maximum limits 74 11 12 13 14 15 16 17 h a o N 10 What method other than the pressure gag Is used to indicate low agent pressure in a container Some aircraft are equipped with a low pressure warning light m the cockpit What is the purpose of the yellow and the red discharge plugs in a turbirie engine fire extinguishing system The ye
23. enger pump 15 Explain the operation of a Cuno oil filter 16 Using reference material and a list of oils match oils that may be mixed for two specific engines 79 IGNITION SYSTEMS ORAL 1 What is a magneto A magneto s a special type of engine driven AC generator that uses a permanent magnet source of energy The magneto develops a high voltage which is used to fire the spark pit 2 What is the purpose of the condenser in a high tension magneto electrical system To prevent arcing at the points and to hasten the collapse of the magnetic field around the primary coil 3 Where is the E gap position In a magneto The E gap position is when the rotating magnet is a few degrees past the neutral position l 4 What are the three major circuits of a high tension magneto systeme The magnetic circuit the primary electrical circuit and the secondary electrical c rcuit 5 What are the components of a high tension magnetic circuit The magnetic circuit consists of a permanent multipole rotating magnet a soft iron core and pole shoes 6 What happens when the primary breaker points open in a magneto Opening the breaker points stops the flow of current in the primary circuit and allows the magnetic rotor to quickly reverse the field through the coil core This sudden flux reversal produces High rate of flux change In the core which cuts across the secondary coll of the magneto Inducing the palse of high Voltage cur
24. ere are the engine operating limitations found In the Aircraft Specifications or Type Certificate Data Sheet Where can a mechanic look to identify an aircraft engine On the engine identification plate that is affixed to the engine at an accessible location What publication is needed to inspect an engine for conformity with specifications The Engine Specifications or Engine Type Certificate Data Sheet What type of FAA approval is required when a change to an engine type design is not enough to require a new Type Certificate A Supplemental Type Certificate is required What type of FAA approval is required when a change is made to the engine principle of operation A new Type Certificate must be obtained 71 NOM PB w 10 ENGINE INSPECTION PROJECTS Inspect an engine and determine conformity with the Engine Specifications or Engine Type Certificate Data Sheet Make a check list for a 100 hour inspection that includes the scope and detail of the requirements set for the in FAR Part 43 Appendix D Perform a 100 hour inspection and list any discrepancies found Inspect an aircraft engine and determine If it Is in compliance with a specific Airworthiness Directive Inspect aircraft engine accessories for conformity Check engine controls for freedom of operation Review aircraft maintenance records and determine compliance with the required Airworthiness Directives by inspection of the engine Find and list all t
25. erts ridirhally t iWiser The ignition system is nortnally required only for starting or restarting an engine IGNITION SYSTEMS PROJECTS Remove and reinstall an engine ignition harness Check the serviceability of high tension ignition leads Locate an open or a ground In an ignition switch circuits Test several condensers and determine if each is serviceable Test a set of spark plugs for one engine and determine return to service quality Select the proper spark plugs and install them in an engine Using reference material and instructions fabricate an ignition lead to specifications 81 8 Inspect magneto breaker points and determine serviceability 9 Check the internal timing of a magneto 10 Disassemble a magneto identify all the major parts and reassemble the magneto 11 Install a magneto on an engine time ma magneto to the engine and determine return to service quality by engine operation 12 Timea distributor to the engine 13 Check the strength of a rotating magnet installed in a magneto and determine return to service quality 14 Install turbine engine igniter plugs and check for proper operation 15 Using reference material inspect a turbine engine ignition system FUEL METERING SYSTEMS ORAL 1 Where are the fuel spray nozzles located in a turbirie engine They are located either externally or internally on the combustion chamber in such a way that the fuel can be sprayed into the combustio
26. ge of fuel from the accelerating pump wil temporary enrich the mixture in the venturi 82 10 11 12 13 14 15 16 17 Describe the purpose and operation of a venturi The venturi performs three functions It proportions the fuel air mixture lowers the pressure at the discharge nozzle and limits the airflow at full throttle What is the function of a metering jet The main metering jet is placed in the fuel passage between the float chamber and the discharge nozzle Its purpose is to limit the fuel flow when the throttle valve is wide open What Is the fuel metering force ina float type carburetor It is the differential pressure perwgen the pressure in ihe float hamber and that at the nozze What will be the result of using excessiv ly rich idle mixtures j P RCOSSIVEIY rich idle mixtures will cause spar pid foio What is the purpose of the economizer ayan ina float carburetor The economizer is essentially a valve which i is dosed at throttle atings pele 60 to 70 of rated power but provide additional fuel for cooling the engine to Prevent detonation at higher throttle settings Where does a pressure injection carburetor obtain tiel presstie SEC It obtains fuel pressure from the boost puinp for starting and from ihe engine e driven fuel pump for normal operation of the engine a 3 porot What operates an automatic mixture control AMC on a pressure car
27. general classifications of superchargers used in Seas engine Induction systems They are classified as Internally driven or externally driven turbocharger supercharger systems What Is the purpose of a distribiition impelier in a supercharger It is designed to break up the fuel globules into finer particles for better distribution to the cylinders 86 10 How does an internally driven poroaren A high speed Impeller is driven through l varies from 6 1 to 12 1 11 Where does an externally driven sup rchs i The exhaust gases are directed against For this reason they are commonly called turbochargers BEE 12 What unit regulates the amount of extia the turbIn of a turbocharger The waste gate 13 What type of power is used to conitl the Ositi t the turbocharger waste gate on some engines P Oil pressure to an actuating pi kei to form 2 Ona drawing of a turbine so protection 4 Check the operation of a ca Remove clean and reinstall h i T SAR ied 3 S that might cause ier ine a malfunction 15 From a list of turbocharger malf reaching critical altitude ENGINE COOLING SYSTEMS ORAL 1 What is the most common means of regulating the cooling alr flow through a radial engine By the use of cowl flaps 2 What is the purpose of the fins on engine cylinders To increase the effective size of the cylinder for cooling 3
28. he information from an engine data plate Check an engine for fluid leaks after engine operation and determine return to service quality Inspect an aircraft engine for compliance with a service bulletin SYSTEMS AND COMPONENTS ENGINE INSTRUMENT SYSTEMS ORAL What are the units in an engine fuel flow system The system eateiats of a transmitter and an indicator for each engine Where is the fuel flow transmitter located l It is mounted in the fuel line between the engine driven pump and the carburetor What type of readout is indicated on a fuel flow system The diester is calibrated to record the fuel flow in pounds of fuel per hour What Is the reason for monitoring the fuel flow In addition to fuel consumption the operator can determine from the fuel flow indication whether the ngine is operating at the correct fuel alr mixture for a given power setting What does a manifold pressure gage indicate It measures absolute pressure in the intake manifold What would be the effect of a broken manifold pressure gage line A broken line will cause the gage to indicate atmospheric pressure 72 10 na ww LP o N Q 11 12 13 14 What does the engine tachometer indicate It indicates crankshaft speed rpm What are turbine engine tachometers designed to indicate They are designed to indicate percent of rotor rpm What is turbojet EPR it is a ratio between total turbine discharge pressure to total inlet pres
29. he piston is In the prescribed position The magneto rotor must be in the E igap position the breaker poirits tet Open andl this distributors must be aligned with that cylinder In a dual magneto ignition system what part of the system Is grounded when the ignition switch is placed i in the RIGHT position The left magneto circuit will be grounded What is internal timing of a magneto _ It is adjusting the breaker points to open when the rotating magne isa at the E gap position foi ade gh tock What is the purpose of an impulse coupling used with a magneto The purpose of an impulse Sling is to Spin the y magnets rapidly to produce a hot spark for starting the engine and at the Same time retard D ee of the p e What is staggered Ignition timing METOS It is the firing of oie sparkplug before the othef one instead of firirig therh simultaneously What Is the proper spark plug reach nir The proper spark plug reach is when the garadi ena of th ee isi t the eloslitdar is in the best position to achieve ignition What ype Jgntion system fs is used in most turbine engines s ee ee A typical turbihe engine is equipped wth an electronic capacitor type ignition un What is the function of the igniter plugs i in a turbine engine The function of the igniter Gn Is to provide a areal gap for ie current which i is stored in T ity When are turbine engine anio ayet
30. ion to the cartridge Service a CO2 fire extinguisher bottle Check a manually operated fire extinguishing agent discharge handle for proper operation without discharging the agent Use a fire detector test unit and verify the proper operation of a fire detector 75 ENGINE ELECTRICAL SYSTEMS ORAL 1 How would you seat newly installed generator brushes to the commutator When new brushes are installed in a generator the face of the brushes must be shaped to provide an area of maximum contact with the commutator To seat the brushes use number 000 sandpaper placed around the commutator with the sanding surface facing outward Turn the armature in the normal direction of rotation until the face of the brushes Is properly contoured Remove the sandpaper and blow out any residue with compressed alr 2 Where is the generator rating and performance data located It is stamped on the name plate attached to the generator 3 What units make up a DC generator three unit regulator The voltage regulator the current limiter and the reverse current cutout 4 What method is used to control the voltage of an aircraft alternator The frequency depends upon the speed of rotation of the rotor and the number of poles 5 What determines the frequency of the voltage of an alternator The frequency deperids upon the speed of rotation of th rotor and the number of poles 6 Howis alternator frequency maintained By installing a constant speed dr
31. ive CSD unit between the engine and the alternator 7 What are the three basic types of DC motors Series motors shunt motors and compound motors 8 Name the parts of a DC motor The armature the field the brushes and the frame 9 Whatisa starter generator system used on many turbine engines The system uses a starter generator which operates as a starter motor to drive the engine during starting and after the engine has reached a self sustaining sere it operates as a generant to supply the electrical system power 10 What is the American Wire Gage AWG system of designating electrical wire size A gage number is assigned the wire epeordiig to its Cross sectional area The smaller the gage number the larger the wire f ao 11 What is open wiring Open wiring is any wire ware group or wire bundle not enclosed in conduit 12 What method Is used to gonial the voltage of DC aircraft generators The only practical means of regulating generator voltage Is to control the strerigth of the magnetic field Field strength is determined by the amount of current flowing through the field coils and the current is controlled by placing some form of variable or intermittent resistance in the external field circuit of the generator 76 13 What are the causes of excessive arcing at the generator brushes Arcing can be caused by a commutator that is dirty rough or out of round A more common cause of arcing Is worn or bi
32. leaks ahd security Determine if a fuel pressure warning light operates within prescribed limits Check a fuel selector valve for proper operation Locate a turbine engine fuel neater and identify alt the connections INDUCTION ENGINE KEATON SYSTEMS ORAL What are the three major pars of a reciprocating engine induction system The airscoop and ducting the carburetor and the intake manifold What effect does induction system icing have on n engine performance Induction system icing can cause an engine to act erratically and lose power What method Is used to prevent or remove induction system ice ina reciprocating engine The most common method of preventing or romong ice formation in the induction system is by the use of heated air How is ice cleared in some aircraft induction systems if the carburetor heat is too low to clear the ice A fluid such as alcohol anilol or mersol is sprayed into the induction system ahead of gl carburetor The fluid will dislodge the ice which is ingested by the engine What engine indication can be the result of a dirty air filter Low powet What is the danger of using carburetor heat when operating at high power settings The higher alr temperatures could cause detonation and possible engine failure Carburetor throttle ice is most likely to form when the throttle is in which position During part throttle operation when the throttle is near the closed position What are the two
33. llow plug indicates normal discharge and the ted plug indicates thermal discharge What are two methods commonly used ta distribute the fire extiiguishing agent to the engine Many systems use perforated tubing or discharge nozzles to distribute the agent How does the fire extinguishing agent pute out the fire AE A It dilutes the atmosphere so that it will not support c combustion ore What is a HRD fire extinguishing system High Rate of Discharge a ie l How is the fire xtinglistitig agent distributed trom a e system It is delivered from open end tubes Bitar tyne How long does it take to discharge the extinguishing a agent in a 1 HRD syste It takes only 1 to 2 seconds ENGINE FIRE PROTECTION SYSTEMS PROJECTS Identify the different types of fire detection sensing units Inspect a continuous loop fire detection system and point out any damaged areas Make a continuity check of a fire detection system locate a fault and repair the system Inspect a fire extinguishing system blowout plugs and determine if the pressure is within the allowable limits Check the pressure in a fire dinauisher Battier and determine if the pressure is van di allowable limits Inspect a fire extinguisher container discharge cartridge for service life and determine return to service quality Checka fire extinguisher cartridge discharge circuit for continuity with a voltmeter by removing the electrical connect
34. material remove and reinstall a float carburetor without error Using reference material remove and reinstall a needle type mixture contro valve in a float type carburetor Inspect a float needle and seat in a float carburetor by removing the needle examining the needle and seat determining their serviceability and reinstalling the needle Identify major carburetor components Using reference material locate inspection procedures for a water injection systems components Remove clean and reinstall a fuel inlet screen as prescribed by reference material Locate and point out the main discharge nozzle in a pressure carburetor Identify the parts of an accelerating pump for a float carburetor Disassemble a float carburetor and point out the alr bleed system inspect an AMC and JES if the unit is serviceable Remove list the size and reinstall a main metering jet in a carburetor Eel T Remove inspect and reinstall a direct injection fuel nozzle BG ENGINE FUEL SYSTEMS ORAL What is the purpose of strainers in a fuel system They are used to prevent foreign matt r from entering the carburetor What is the purpose of fue selector valves l They provide a means of shutting off iuel flow tor tank and engine selection for crossfeed and for fuel Muransfer ge be E Aa aien a i i What should be looked for when inspecting an engine driven fuel pump Look for fuel leaks and Security of riounting What is
35. n area 2 Name two heat sources for the operation of fuel heaters used in turbine engines Tutbirie engine fuel heaters operate as Heat exchangers Fuel lines are routed through the fuel heater which ESES as a heat source either bleed air or engine Jubricating oil If bleed air is used as a h at souiree it s called an air to Jiquid heat exchanger a and ee oil Veu used it is called a liquid to liquid heat exchanger os o gt G 3 What ngine varighles are ranged by a Fysromechanteal fue control D a The fuel Control senses power lever position engine rpm either compressor inlet pressure or temperature Durnag pressure or compressor discharge presstre and either EGT or TIT 4 What are the two most commonly used carburetors in small reciprocating engines They are the float type carburetor and the pressure type all 5 What type fuel control unit is used In a turbine engine Both hydromechanical and electronic fuel control units are in use today r owever the most commonly used fuel control unit is the complet ly tiydromtechanital type 6 What is the purpose of a mixture contro in a float type carburetor It is to contro the fuel air mixture as air density changes with changes in altitude 7 What is the purpose of an accelerating system on a float type carburetor When the throttle is opened rapidly the fuel air mixture will flean out momentarily To overcome this tendency a char
36. nding brushes or the brush spring tension too low 14 When installing single wires or wite bundles liiw much fick is normally allowed between siupors Slack boaon supports should normally 0 not exceed one half inch 15 What recaution should be taken vihen running wires dass to heating ducts or siete stacks The wires shoud be insulated wa a high oppet material Juo i E i iig Li S ENGINE ELECTRICAL SYSTEMS PROJECT S 1 Use the engine electrical system service manual and locate required reference material to repair five different electrical components 4 2 Meas gh 2 Use an electrical system parts catalog and locate the part number for five different components 1 that areto be replaced oop ord REEE 3 Remove and reiristall an engine driven generator in accordance with reference material 4 Check an engine driven generator by running the engine and determining whether generator operation is within limits 5 Remove old brushies fro mM a DG generator and Install and seat new brushes 6 Locate and replace thie revetse current cutout relay i in the generator electrical system 7 Using reference material parallel a dual generator system to the limits prescribed in given reference material 8 Remove and reinstall a direct drive electric starter motor 9 Remove ard reinstall a new starter solenoid 10 Fabricate an alternatof el ctric cable by sel cting the poper cable size and insiating t
37. o the propeller blades PROPELLER PROJECTS 1 Using reference material check vertical and horizontal unbalance on a twoblade propeller and determine if the propeller is within balance limits as prescribed 2 Install oil control plugs in a governor 3 Determine the direction of rotation for which a governor Is set 4 Measure propeller blade pitch angle 92 N o p 8 9 Clean and protect aluminum propeller blades Detect and correct front cone bottoming of a propeller installed on a splined shaft Adjust a propeller governor so that the propeller will operate within the correct range Remove inspect and reinstall a propeller governor Lubricate a prop ller as prescribed by reference material h of the oil flow for an on speed an
38. rent a the satel needed to fire the spark plugs 7 What is the piston position when the spark gecurs in a cylinder The piston is a specified number of crankshaft degrees before top dead center of the compression stroke 8 What is a dual een a system E The duai magneto system Ineorporates tv two magnetos in one kausa and one rotating magne and a cam dre common to two sets of breaker points and coils On radial engines the right magneto fires all the front plugs and the left magnetan fires all na rear plugs 9 What is the ciference between a low tension and a high tension ignition system 2 In the high tension system high voltage is generated in the magneto and flows to the plugs through igt tension leads In the tow tension system low voltage is generated n the magneto and flows through tow tension leads to the primary winding of a transformer coil located near each spark plug There the voltage is Increased to high voltage by transformer action and is conducted to the plugs by very short high tension leads 10 When the ignition switch is in the OFF position what is the condition of the primary circuit _ it is completed through the ignition switch to ground 80 tat aud tte p me gi edge Sahai as anp Ee aani SH year aal apia ma N een na A a a PAE bk A ZA Bs 3 11 12 13 14 15 16 17 18 19 What three conditions are required to fire the plugs in a cylinder when t
39. ressure in accordance with reference material Demonstrate Gorrack engine starting procedures ay Wen eee dee Bees IR Operat an engine throughout the normal operating range and check for proper operation in accordance with the operating instructions 8 Use a c cold cylinder Indicator and locate a cold cylinger atter an engine runup 9 Using r fer nce matatial correctly remove e nd reinstall a propeller 10 conaeily identity all the parts of an air cooled cylinder ight all the parts of a y ckankshatt nspect a crankshaft record the dimensions aw determine t the thee sing tefererice mat rankshatt is within tolerance to meet return to service quality Be Ane aa 13 Correctly identify various types of bearings and determine Jf they are return to service quality 14 Measure the inside diameter taper and ono of a Leyiinder bore and determine if it is retum to 2 gerviae aval do ons Ce ae eS eee ye HE RR Paes 15 Using reiste ange alia heii and adjust valve Alaa within hacen limits ae SF ne 16 Correctly disassemble an articulating rod from a master rod ee and reassemble according to manufacturer s instructions 17 Adjust a mechanical push pull control system in accordance with rofar nce material 18 Install a piston pin a knuckle pin and the retainer without damage to the components 68 9 a TURBI
40. rline cracks on or across the leading or trailing edge of the blades The cracks appear at right angles to the edge length How are compressor blades attached to a disk type rotor The compressor blades are fitted into the disks by either bulb type or fir tree type roots The blades are then locked by means of screws peening locking wires pins or keys 10 What is the purpose of the nozzle diaphragm or turbine nozzle First the turbine nozzle must prepare the mass airflow for driving the turbine rotor The stationary vanes are shaped and set at such an angle that they form a number of small nozzles that discharge the gases at extremely high speed That is they convert a portion of the heat and pressure energy to velocity energy to drive the turbine The second purpose of the turbine nozzle is to deflect the gases to a specific angle in the direction of turbine rotation 69 11 12 13 14 15 16 17 oO o ND What is the major difference between a turboprop and a turbojet engine A turboprop engine usually has more turbine stages than the turbojet engine In addition to operating the compressor and accessories the turboprop turbine must also drive a propeller What is a turbofan engine A turbofan engine is in principle the same as a turboprop except that the propeller is replaced by a duct enclosed axial flow fan wet is the effect of air density on the thrust of a turbine engine Air density
41. sure and is an indication of thrust being developed by the engine What is the electric source for a cylinder head temperature gage The gage Is connected to a thermocouple attached to the cylinder which tests show to be the hottest on the engine Where is a carburetor air temperature bulb located It is located in the alr intake passage to the engine How cana turbine engine EGT be checked without operating the engine By checking resistance to thermocouples and circuits ENGINE INSTRUMENT SYSTEMS PROJECTS Measure the resistance of thermocouple leads Check a manifold pressure gage for proper operation Repair a leaking manifold pressure system Locate and repair a loose line on a turbine engine EPR system Inspect EGT probes and determine their return to service quality Locate and inspect fuel warning low pressure system components Remove and reinstall a carburetor air temperature thermocouple Replace a cylinder head temperature thermocouple assembly and check for proper operation Inspect an rpm gage for proper markings by reviewing the engine operating limitations Locate and inspect fuel flow system components Remove and reinstall a fuel flow gage l gt Remove and reinstali a fuel flow transmitter Measure the electrical power supply to a fuel fow transmitter Remove and reinstall turbine engine EGT harness 73 ENGINE FIRE PROTECTION SYSTEMS ORAL 1 What types of fire detectors are used for engin
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