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288 Cards in this Set
- Front
- Back
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What procedure should be followed when valve blow by is indicated by a hissing sound on a reciprocating engine? |
Perform a cylinder compression test to identify the faulty component |
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What is the running valve clearance on engines equipped with hydraulic valve lifters? |
Zero |
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What type of check can be made to locate a cold cylinder in a twin row radial engine? |
A cold cylinder check |
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What factors about the condition of an engine can be learned by studying the results of a compression check? |
It determines if the valves, piston rings and pistons are adequately sealing |
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What should be done to repair a loose stud in an engine crankcase? |
Remove the loose stud and check hole for size and condition of threads. It may be necessary to retap, and use a oversize stud |
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How is a cylinder barrel checked for being out of round? |
A bore gauge equipped with a dial indicator can be used to measure the bore of the cylinder at the top of the cylinder and at the skirt. 2 measurements at each spot should be taken 90 degrees from each other |
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What type of connecting rods are commonly found in a radial engine? |
Master and articulating rods |
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What are the different types of piston rings? |
Compression, oil control, and oil scraper |
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What is the purpose of oil control rings? |
Regulates the thickness of the oil film on the cylinder wall. |
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What type of bearings are in general use in reciprocating engines? |
Plain, ball, and roller |
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Where are cracks most likely to be found in a piston? |
In highly stressed areas such as the base of piston pin bosses, inside the junction of head and walls, and ring lands. |
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What are the different types of reciprocating engines? |
In-line, opposed, v-type, and radial |
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What is the purpose of valve overlap? |
Permits better volumetric efficiency and lowers the cylinder operating temperature |
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What is the purpose of crankshaft dynamic dampers? |
Absorbs the power impulses and reduces vibrations |
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What are the causes for engine sudden stoppage? |
A prop strike or seizure due to internal damage |
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What inspection must be made after sudden reduction in speed of engine due to striking an object? |
- Make a thorough external inspection of engine mounts, crankcase and nose section to determine if any components are damaged. |
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What are some of the precautions to be observed when engine removal is being accomplished? |
Disconnect battery, support the tail, chock wheels, turn fuel valves off |
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What is the indication of a primer that is leaking during operation? |
Engine will not idle properly |
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What may be the result of incorrect installation of piston rings? |
Excessive oil consumption, also blow by past the rings |
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What is the indication of an induction leak? |
Low power and uneven running |
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What are the major components of a typical gas turbine engine? |
Inlet, compressor section, combustion section, turbine section, exhaust section, accessory section |
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What determines the amount of air passing through a turbine engine? |
Compressor speed, air density, and forward speed of the aircraft |
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What are the two principal types of compressors currently used in turbojet aircraft engines? |
Centrifugal and axial flow compressors |
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How are rotor blades attached to disk type rotors? |
By the turbine blade root. (Fir tree or bulb type) |
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What are the three types of combustion chamber systems? |
Multiple can, can annular, annular |
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What is the purpose of the interconnect tubes attached between can type combustion chambers? |
For flame propagation during starting |
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What prevents burning combustion chambers? |
Cooling air along the inside wall of the liner |
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What is a split compressor system? |
Two concentric shafts joining the turbine stages to their respective compressors |
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Where are carbon seals used in turbojet engines? |
In oil seals for bearings |
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What is the major difference in turboprop and turbojet engines? |
Turboprop engines usually has more turbine stages than a turbojet. In addition to operating the compressor and accessories the turboprop engine turbine drives a reduction gearbox and propeller |
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What is a free-turbine? |
A turbine engine that uses a separate turbine that is not mechanically connected to a compressor to drive a propeller |
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What is a turbofan engine? |
Very similar to a turbojet engine except with a duct enclosed fan |
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Name an advantage of turbofan over turbojet? |
Additional thrust without increasing fuel flow |
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What are the functions of axial flow turbine nozzles? |
- Direct the flow of hot gases to strike the turbine rotor at the correct angle |
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What is one way of relieving thermal stress on a turbine disk? |
By directing bleed air on to the face of the disk, or by grooving in the turbine disk |
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What type of compressor blade damage may be found when inspecting compressor blades? |
Dents, galling, pitting, cracks, scratches, burrs, burns, and gouges |
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What is used to mark combustion system parts for disassembly? |
Layout dye or chalk |
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What is the effect of relative humidity on turbojet power? |
Has a negligible effect |
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What may be the indications if a turbojet engine is out of trim? |
Engine has high exhaust gas temperature at engine pressure for takeoff power |
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What would the possible cause be for a turbojet engine with high egt, low rpm, and high fuel flow at all engine pressure ratio settings? |
Possible turbine damage or loss of efficiency |
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What functions need to be accomplished in order to prepare an engine for a 100 hour inspection? |
Clean the aircraft & remove the cowling |
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How can a mechanic visually identify engines? |
By the engine data plate |
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What may be used as a guide for 100 hour inspections on aircraft engines? |
FAR part 43 appendix D |
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What additional inspection must be performed if a cylinder's compression is weak? |
Internal cylinder inspection |
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Where are engine operating limitations listed? |
TCDS or Engine specifications |
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Why is the spectrometric oil analysis program used on turbine engines? |
To evaluate the internal condition of the engine |
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What type of FAA approval is required when a change to an engine type design is not enough to require a new type certificate? |
An STC can be issued |
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What AD's would apply to a specific engine? |
Review AD's and bi-weekly |
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What publication is needed to inspect an engine with conformity specifications? |
Engine Specifications or TCDS |
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What publication is need to check an engine for normal operation? |
Manufacturer's operation manual |
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What is the purpose of a hot section inspection? |
To determine the mechanical integrity of an engine |
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When is an aircraft engine service bulletin compliance mandatory? |
When it is part of an AD |
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How can a turbine engine be leak checked without running the engine? |
Motor the engine starter with ignition and fuel off |
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What publication is needed to perform a turbine engine over-speed inspection? |
Manufacturer's maintenance and service publications |
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What kind of inspection is required after a turbine engine experiences exhaust gas over-temperatures? |
A hot section inspection |
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Where do you find a list of life limited parts? |
TCDS or inspection and limitations section of the manufacturers maintenance manual |
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What criteria is used to determine the replacement of life limited turbine engine components? |
Cycles, hours or calendar time |
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How often should the humidity indicator be inspected on metal containers storing engines under normal conditions? |
every 180 days |
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When removing and inspecting turbojet turbine blades why is it important that they be installed in the same location? |
To maintain balance of the turbine wheel |
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What must be included in a checklist for 100 hour inspection of an aircraft engine? |
Run the aircraft to determine satisfactory performance in accordance with the manufacturer's recommendations of power output (static and idle RPM), fuel and oil pressure, and cylinder and oil temperature. |
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In reference to a reciprocating engine, where is a fuel flow indicating system generally connected in an engine fuel flow system? |
Between the engine fuel pump and the carburetor |
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What basic components are used in an engine fuel flow system? |
Transmitter and indicator |
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What type of readout is indicated on a fuel flow system? |
Amount of fuel flow in pounds/gallons per hour |
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What is the fuel pressure range of a float type carburetor? |
3 - 5 psi |
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What is the reason for monitoring fuel flow? |
Fuel flow is an indication of fuel consumption and engine performance |
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What does a manifold pressure gauge indicator? |
Absolute manifold pressure in inches of mercury |
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What directly controls manifold pressure? |
Engine rpm and throttle opening |
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On an engine equipped with a fixed pitch propeller what is the relationship between manifold pressure and rpm? |
As RPM increases, MAP increases |
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What does a reciprocating engine tachometer indicate? |
Engine crankshaft speed |
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What are turbine engine tachometer gauges designed to indicate? |
Percent of rotor RPM |
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What is indicated by turbine egt? |
Average temperature measured by individual thermocouples in the exhaust tailpipe |
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What does turbine engine pressure ratio indicate? |
The amount of thrust being produced |
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What pressures are measured to obtain engine pressure ratio? |
Total inlet pressure and total turbine discharge pressure |
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What is indicated by a turboprop torquemeter gauge? |
Torque being developed by the engine issued to indicate shaft horsepower |
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Where should the thermocouple be installed on a single probe cylinder head temperature system? |
On the hottest cylinder |
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What is the electrical source for cylinder head temperature systems? |
Thermocouple |
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Where is the location of the carburetor air temperature bulb? |
In the ram air intake duct |
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What is the possible cause when oil pressure drops off severely, oil supply remains full, and oil temperature is normal? |
Oil pressure transmitter or indicator malfunction |
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How can a turbine egt system be checked without running the engine? |
By checking the resistance of thermocouples and circuits |
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When checking the manifold pressure during runup or operation, in what position should the prop control be set? |
High rpm/low pitch |
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Name two types of fire detector systems used for engine fire protection. |
- Overheat |
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What will happen to a thermocouple fire warning system on an engine that overheats slowly? |
Nothing, because it takes rapid rate of rise to trigger a warning in a thermocouple system |
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What happens to a thermal switch fire detection system when it is heated enough to operate? |
An electrical ground is provided for a red warning light |
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What electrical power is needed for a thermocouple fire protection system? |
Aircraft electrical system and themocouple produced voltage |
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What is the minimum number of thermal switch units need for a thermal switch fire protection system? |
At least one |
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What is a type of fire protection system that covers more area than a spot type temperature protection system? |
Continuous loop system |
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What is the principle of operation of a kidde continuous loop fire detection system? |
Two wires imbedded in a special ceramic core within an inconel tube. One wire is a ground and the second is a hot lead that provides current when the ceramic core material changes its temperature due to temperature |
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What is the principle of operation of a fenwal continuous loop system? |
A single wire is surrounded by ceramic beads in an inconel tube. The resistance is lowered with temperature rise |
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What is the purpose of a fixed fire extinguishing system? |
To discharge an inert agent that will not support combustion |
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What methods are used to distribute fire extinguisher agents? |
Perforated tubing or discharge nozzles |
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What is an HRD fire extinguisher system? |
A high rate of discharge system |
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How is an HRD fire extinguished system agent distributed? |
Open end tubes |
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How long does it take to discharge an HRD agent? |
One to two seconds |
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What fire extinguishing agents are used for aircraft engines? |
Carbon dioxide, freon and halon |
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What methods are used for discharging fire extinguishing agents? |
Mechanical or mechanical |
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What is the purpose of the discharge cartridge in a turbine engine fire extinguisher system? |
To release the agent electrically |
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What is the purpose of the red and yellow discharge plugs associated with a turbine engine fire extinguisher system? |
Red for thermal discharge and yellow for normal discharge |
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What will happen to an engine fire sensing loop when the sensing loop is excessively kinked or bent? |
It will cause a false fire warning |
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What two items in a turbine engine fire extinguisher system indicate low agent pressure in a container? |
Low pressure warning light and pressure gauge |
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What is the proper method for determining the fire extinguisher container pressure? |
Container gauge pressure will indicate if the pressure is within limits marked on the gauge |
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Where is generator rating and performance data located? |
Stamped on the nameplate of the generator |
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How are DC generator terminals marked? |
A, B, and E |
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What is used to control DC generator voltage? |
Strength of field current |
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What three components make up a vibrator-type DC regulator in an electrical system? |
Current limiter, reverse current cut-out relay, and voltage regulators |
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Why are multi-generator systems paralleled? |
Each generator must share the load |
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How many phases are used in most aircraft AC alternator systems? |
Three |
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What determines the frequency of an alternator output? |
The speed of rotation of the rotor and the number of poles |
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What are the three types of generators used on aircraft engines? |
Series wound, shunt wound, or compound wound |
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How does the voltage regulator control the voltage of an alternator? |
By regulating the voltage output of the d.c. exciter |
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What is the probable cause of an engine started that operates but does not turn the crankshaft? |
Starter not engaging due to damaged pinion or crankshaft |
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What is the purpose of bonding wires on a powerplant installation? |
To provide current return paths, prevent static discharge, and protect the aircraft and personnel from lightning discharge |
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What is the primary purpose of an aircraft reciprocating engine lubricant? |
Reduce friction between moving parts |
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What is one of the most important properties an aircraft reciprocating engine oil must possess? |
Viscosity |
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What is the most critical lubrication point in a gas turbine engine? |
Exhaust turbine bearing |
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What happens to oil at high temperatures? |
Oil becomes thin |
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What factors must be considered in determining proper grade of oil? |
Operating load, rotational speeds, and operating temperature |
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How much does aircraft engine oil weigh per gallon? |
about 7 pounds per gallon |
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Why must reciprocating engines use an oil with high viscosity? |
Large operating clearances, high operating temperatures, and high bearing pressures |
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Why is an oil tank required to have expansion space? |
To provide for expansion and foaming of oil |
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What is the purpose of an oil cooler bypass valve? |
Directs oil through or around the cooler to keep the oil temp within operating limits |
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What does the oil temperature bulb usually sense? |
Engine oil inlet temperature |
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What does the presence of metal particles in an engine oil screen indicate? |
Possible engine internal failure |
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What are two areas of an engine oil system where oil screens may be located? |
Oil pressure system and scavenge system |
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What are some oil contaminants? |
Gasoline, moisture, acids, dirt, carbon, and metal particles |
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What type of oil is usually used in turbine engine oil systems? |
Synthetic oils |
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What could be the cause of excessive oil consumption without evidence of oil leaks? |
Worn or broken piston rings |
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What would be an indication of inadequate oil supply? |
Low oil pressure and high oil temperature |
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What would be an indication of an obstruction in oil cooler passages? |
High oil temperature |
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What could cause oil foaming? |
Diluted oil, contaminated oil, and oil level being too high |
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What are two types of turbine engine oil coolers? |
Air cooled and fuel cooled |
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What controls oil pressure in a gear type oil pressure pump? |
Pressure relief valve |
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Why is it necessary to cut open a can cartridge type oil filter after removal? |
To inspect the filtering element |
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What is the advantage of multi-viscosity oils? |
Wider operating temperature ranges |
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What is the purpose of a magneto? |
A magneto produces a high voltage which forces a spark to arc across a spark plug gap |
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What are the three major circuits of a high tension magneto system? |
Magnetic, primary, and secondary |
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What are the components of a high tension magnetic circuit? |
Permanent rotating magnet, soft iron core, and pole shoes |
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In terms of the engine crankshaft degrees, when does the ignition event occur? |
A specified number of crankshaft degrees before top dead center of the compression stroke |
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What is the e-gap position? |
The point where magneto contact start to open. A few degrees beyond neutral |
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What is the purpose of the condenser/capacitor in a magneto? |
Prevents arcing at the contact points, and facilitates a more rapid collapse of the primary field |
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What happens when a magnetic rotor is int the e-gap position and the primary breaker points open? |
It interrupts the primary circuit and induces a pulse of high voltage into the secondary coil |
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What re the two purposes of a high tension ignition harness? |
Supports the wires and protects them from damage by engine heat, vibration, or weather; serves as a conductor for stray magnetic fields and eliminates/electrical radio interference |
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When an ignition switch is off, what is the condition of the ground circuit? |
The circuit to ground is complete. Magnetos are grounded |
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What is the purpose of a dual magneto ignition system? |
System redundancy (safety factor) and improved combustion efficiency |
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How can you identify a low tension ignition system? |
By the presence of an external transformer coil and short high tension leads. |
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Which magneto is grounded when the magneto switch is selected to the right magneto? |
Left mag is grounded |
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What is meant by spark plug reach? |
The distance from the gasket surface to the end of the threaded area |
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What re the three events required to fire a spark plug in a cylinder when its piston is in the prescribe position? |
Magneto is in e-gap position, breaker point are opening, and the distributor electrically aligned with that cylinder |
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What is the purpose of a magneto timing light? |
It determines the exact instant that the magneto points open |
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How can top dead center of a piston be located? |
A piston indicator or timing disk |
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What are the factors involved in the magneto internal timing? |
E-gap position and distributor rotor position |
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What is the most common type of ignition system used on turbine engines? |
Capacitor discharge |
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When are turbine engine ignition systems used? |
For starting, or when in-flight conditions call for flame-out protection |
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What type of igniter plugs are used in turbine engines? |
Self-ionizing or shunted gap |
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What is the purpose of water injection? |
Enables more power to be obtained from engine at take off power, also to prevent detonation. Commonly referred to as ADI. (Anti-detonation injection) |
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What happens to fuel/air mixture in a reciprocating engine when the water injection system is operated? |
The mixture can be leaned to allow the engine to produce maximum power since a rich mixture is no longer needed for cooling. |
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What are the two types of carburetors most commonly used on small reciprocating engines? |
Float type and pressure type |
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What is the function of a mixture control on a float-type carburetor? |
Controls the fuel/air mixture |
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What is the action of a float type carburetor accelerating system when the throttle is opened with a quick action? |
A charge of fuel will enrich the mixture |
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When does a carburetor economizer need valve open? |
Above approximately 60 - 70 percent of rated power |
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What is the purpose of a carburetor economizer system? |
To provide additional fuel at high powers for cooling and to prevent detonation |
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Where does a pressure injection carburetor obtain fuel pressure? |
From the engine fuel pump |
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What operated an automatic mixture control? |
A sealed bellows that contracts or expands with change in altitude (atmospheric pressure) |
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What position of a pressure injection carburetor manual mixture control would stop an engine? |
Idle cutoff position |
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What are the operating principles of direct fuel injection systems? |
Measures engine air consumption, uses air flow forces to control fuel flow, and supplies fuel from an injection pump directly to each cylinder |
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Why should a pressure type carburetor be filled with fuel and allowed to soak for 8 hours prior to installation? |
To soak the diaphragms and render them pliable to the degree they were when the unit was originally calibrated |
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What is the problem caused by excessively rich mixtures at idle? |
Spark plug fouling |
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What is the indication of rpm when an idle mixture is set correctly, and the mixture control is placed to the idle cutoff position? |
A slight rise in rpm prior to decreasing |
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Why should engine rpm be accelerated periodically when making carburetor adjustments? |
To clear the engine |
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What is a function of turbine engine fuel control units? |
To automatically supply the correct amount of fuel to the engine in any condition |
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What are the two basic types of turbine engine fuel control units? |
Hydro-mechanical and electronic |
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What are some of the engine variables detected by a turbine engine fuel control unit? |
Power lever position, compressor rpm, compressor inlet temperature, compressor discharge & burner pressure, and egt or TIT. |
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What are two sources used in turbine engine fuel systems for fuel heat? |
Bleed air and engine oil lubrication |
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How is fuel delivered to a turbine engine burner section? |
From the fuel control to one or more spray nozzles |
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What is another type of fuel metering system used on reciprocating engines other than carburetors? |
Direct injection |
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What is the purpose of engine driven fuel pumps? |
To deliver a continuous supply of fuel at the proper pressure at all times |
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What are the two categories of turbine engine fuel pumps? |
Constant and variable displacement |
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A gear type pump is classified in what category? |
Constant displacement pump |
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What protects an engine from fuel pump seizure> |
Shear section of the shaft |
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What happens to excess fuel not required by an engine in a constant displacement pump? |
The pressure relief valve bypassed excess fuel back to the inlet of the pump |
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What type of fuel pump varies the amount of fuel discharged with any speed? |
Variable displacement pump |
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What is the purpose of a pressurization and dump valve? |
To provide positive cutoff of fuel to prevent fires, coking, and provide positive pressurization for operation |
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What type of engine driven fuel pump is widely used other than gear and piston pumps? |
Rotary vane pumps |
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What is the purpose of fuel booster pumps? |
To supply a fuel under positive pressure to the engine driven fuel pump |
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What is commonly used as a fuel booster pump? |
Centrifugal boost pump |
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What is the cause of vapor lock? |
When fuel vaporizes too readily, low fuel pressure, high fuel temperatures and excessive fuel turbulence |
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Why is vapor lock serious? |
It can completely block the flow of fuel |
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What is the purpose of main line fuel strainers? |
To keep foreign matter out of the carburetor and engine |
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What are the purposes of fuel selector valves? |
Provides a means for shutting off fuel flow, tank and engine selection, crossfeed, and fuel transfer |
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What unit in a turbine engine fuel system is susceptible to the formation of ice? |
Fuel filter |
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What is the safety feature in an engine fuel system micron filter? |
A bypass valve |
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What method is used to prevent ice formation in turbine fuel filters? |
Air-fuel or oil-fuel heat exchangers |
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What is a duplex fuel nozzle? |
A fuel nozzle that has 2 spray patterns |
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What do you look for during external inspection of an engine driven fuel pump? |
Leaks and security of mounting |
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What are the three units in a reciprocating engine induction system? |
Carburetor, airscoop, and induction/intake manifold |
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What is the effect on engine performance when induction system icing occurs? |
Engine power loss and erratic operation |
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What are the three classifications of ice? |
Impact ice, fuel evaporation (carburetor ice) , and throttle ice |
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What method is used to prevent induction system ice? |
Raising the temperature of induction air with a preheater |
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How is ice cleared on some aircraft if carburetor heat is too low to clear the ice? |
Alcohol is used as a de-icing agent |
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When is carburetor throttle ice likely to form due to throttle position? |
During part throttle operation when the throttle is near the closed position |
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What are the 2 types of supercharged induction systems? |
Internally or externally driven |
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What is the function of a distribution impeller? |
Driven by the engine crankshaft, it helps to ensure equal distribution of the fuel air mixture |
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How does an externally driven supercharger (turbocharger) derive its power? |
Energy of engine exhaust gases directed against turbine blades |
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How does an internally driven supercharger driven by the engine crankshaft boost air pressure? |
A high speed impeller compresses the fuel air mixture after it leaves the carburetor |
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What is the function of a turbocharger waste gate? |
It regulates the amount of exhaust gases that drive the turbine |
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What may be the indication of leaking intake pipes? |
Engine runs rough at low rpm |
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What may be the indication of an induction system obstruction? |
Engine fails to start or power is low |
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What may be the indication if a turbocharger waste gate will not close? |
Aircraft may not reach critical altitude |
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What could be the probable cause of turbocharged engine that surges? |
Waste gate controller malfunction |
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What is used on many turbocharge engines for the waste gate actuator power? |
Oil pressure |
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What engine power indication will occur when carburetor heat is applied to an operating engine? |
A loss in engine power |
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What is the danger of applying carburetor heat with high engine power? |
Detonation |
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What happens to the induction air supply in a filtered air induction system when the filter becomes restricted? |
The filter will be bypassed, alternate air door will be opened or a loss of power |
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What is the indication of a dirty air inlet filter? |
Low power |
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What are the main reasons that excessive heat is undesirable in any air cooled reciprocating engine? |
Affects behavior of combustion, weakens and shortens life of engine parts, and impairs lubrication |
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What type of air cooled cylinder construction increases the effective surface area for cooling? |
Cooling fins |
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What is engine cooling? |
Transfer of heat from the engine cylinders to the air |
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What should be done to cylinders with excessive cooling fin area broken off? |
Replace the cylinder |
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What is the principle function of engine cowling and baffles? |
They are designed to direct air flow over the cylinders and engine accessories for cooling |
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What method is used to control air flow through the cooling area of an engine? |
Cowl flaps |
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What is an augmentor cooling system? |
A system incorporating inner and outer tubes that extend from the engine compartment to the rear of the nacelle. The inner tube is fed exhaust gas and the outer tube is open to engine compartment air. The velocity of the exhaust gases creates a venturi effect to draw more airflow over the engine |
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What type of power is used to operate cowl flaps? |
Mechanical linkage, electrical, and hydraulic |
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How are accessories cooled? |
Blast tubes are built into baffles to direct cooling past the accessories |
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Where should cowl flaps be positioned during ground operations? |
Fully opened |
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What information must be consulted prior to re-profiling a cooling fin? |
Manufacture's service publications and manufacturer's overhaul manual |
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What are the functions of an engine cowling? |
Streamlines the engine to reduce drag and controls air flow past cylinders |
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What is the purpose of a cowl air seal? |
Forces air to circulate around and through the baffles |
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Why is cowl flap adjustment important? |
The movement must be within tolerance to keep cylinder head temperatures within allowable limits |
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Where must cooling air flow to cool a turbine engine? |
Through the inside of the engine |
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What areas of a turbine engine are cooled by air passing through the engine? |
Combustion chamber and turbine sections |
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What is the source of bleed air vented to turbine engine bearings and other parts in some engines? |
Turbine engine compressor |
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Other than cooling air, what method is used to cool components and structures adjacent to turbine engines? |
Insulation blankets |
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What does turbine engine insulation protect from heat? |
Structures, leaking fuel and oil from coming in contact with hot engine parts |
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What type of material is used to make turbine insulation blankets? |
Aluminum, fiberglass, and stainless steel |
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How are high temperature noxious gases removed and disposed of in a reciprocating engine? |
By the engine exhaust system |
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What is the function of an exhaust system? |
To provide protection against potentially destructive exhaust gases |
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What are the 2 types of reciprocating engine exhaust systems? |
The open/short stack system and the collector system |
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What type of exhaust system is used on turbocharged engines? |
The collector system |
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What type of exhaust system is generally used on normally aspirated engines? |
The short stack or open system |
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What exhaust system raises engine exhaust back pressure? |
The collector system |
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Why is an exhaust system failure considered a severe hazard? |
Carbon monoxide poisoning, loss of power, or fire |
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Why should lead, zinc, or galvanized marks not be made on exhaust systems? |
The marks cause a change in molecular structure when heated and will cause cracks |
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What is the indication of exhaust gas leaks? |
A flat gray or sooty black streak on the outside of the stack or muffler |
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How are exhaust system internal baffles or diffusers inspected? |
Disassembled for visual inspection, as necessary |
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Why does a failure of exhaust system internal baffles or diffusers sometimes cause a loss of engine power? |
Restricts the flow of exhaust gases |
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What happens to engine power when a heat exchanger leaks exhaust gases into the engine induction system? |
There is a loss of power |
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Where are exhaust manifold and stack failures usually found? |
At welded or clamped points |
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What is a common cause of turbocharger waste gate sticking? |
Coke deposits or carbon build up |
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Why are turbocharged exhaust system leaks very damaging at high altitudes? |
Due to the pressure differential the leak will escape with torch-like intensity that can severely damage adjacent structures |
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What are exhaust system coke deposits? |
Excessive carbon build up |
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What would happen to turbine engine performance if the exhaust nozzle shape is changed? |
The performance and exhaust gas temperature would change |
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What are the components of a typical turbine exhaust nozzle? |
Tail cone, exhaust duct, and support struts |
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What is the purpose of thrust reversers? |
To aid in deceleration after landing |
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What is the function of the thermocouple probes in a turbine exhaust tailpipe? |
Measure exhaust gas temperature |
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How do you determine the reliability of a damaged propeller blade? |
Reference the manufacturer's maintenance manual |
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What is the purpose of propellers? |
To produce thrust to pull or push the aircraft through the air |
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What is a fixed pitch propeller? |
A propeller that has a blade angle built into it that cannot be changed |
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What type of blade angle change will occur on a propeller, that is pitch controlled by a governor, during constant power drive? |
The blade angle increases to overcome overspeeding |
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Other than maintaining constant speed, what are two actions of some controllable propeller systems? |
Reversing and feathering |
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What is the purpose of metal tipping fastened to a wooden propeller leading edge and tip? |
Protect the propeller from damage |
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When engine vibration is reported, what should be checked to determine if it is caused by the engine or the propeller? |
Blade tracking and low blade angle setting |
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What is blade tracking? |
Determining the position of the tips of the blades in relation to each other |
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What may be used to determine propeller blade angle? |
Propeller protractor |
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What should be used to clean aluminum propeller blades and hubs? |
It should be cleaned in accordance with manufacturer's instructions |
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What positions of a two bladed propeller are used during a static balance check? |
Vertical and horizontal |
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What two forces are balanced in a propeller governor in an on-speed condition? |
Spring and flyweight forces |
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On light aircraft propellers, what is the purpose of centrifugal force acting on propeller blade counterweights? |
This action is to increase propeller blade pitch |
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What happens to a constant speed feathering propeller when the propeller governor oil pressure drops to zero? |
The prop will feather |
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What may be adjusted in a hydromatic propeller system to increase or decrease rpm? |
Prop governor set screw |
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What type of systems are used for propeller ice control? |
Fluid (alcohol) and electrical |
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What type of nondestructive testing should be accomplished to the propeller after blending? |
Procedures recommended by the manufacturer |
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What is the function of the negative torque sensing device in a turboprop system? |
Prevents the propeller from driving the turbine and compressor sections of a fixed shaft turbine engine |
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What is the purpose of an oil accumulator connected to a prop governor? |
To provide unfeathering oil pressure |
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How is feathering accomplished on a constant speed propeller? |
Releasing the governor oil pressure allows the counter weights and feathering spring to feather the propeller |
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What unit is used to sense propeller rpm in the light twin aircraft propeller synchronizer? |
The propeller governors have magnetic pickups that count the propeller revolutions and send a signal to the synchronizer unit |
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What places the greatest demand on auxiliary power units? |
Bleed air |
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What starts a typical apu? |
Electrical starter (sometimes a hydraulic pre-charged accumulator) |
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Where does an apu get its fuel? |
From the main fuel tanks |
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What speed does an apu operate at? |
A very high rpm, which is controlled by the apu fuel control and speed sensitive switched if overspeeding occurs |
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How does a heavily loaded apu prevent itself from overheating? |
Air load control valve |
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How do you facilitate the cooling down of an auxiliary power unit prior to engine shutdown? |
Completely unload the apu of all external demands (Air and electrical power) |
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What are the operational effects of following the required cool down cycle? |
It adds longevity to the life of the APU |
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How long is a typical cooling down cycle of an apu? |
3-4 minutes |
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How is the operational speed of an apu controlled? |
APU fuel control adjusts the speed by adjusting fuel flow |
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Name at least 2 uses for an APU? |
Engine start, aircraft ground operarion, bleed air supply for anti-icing |
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What type of operational practices can cause thermal shock to an apu? |
Not following prescribed cool down cycle |
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What powers the variable inlet guide vanes on an apu? |
Fuel pressure from the fuel control unit |
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What does a typical apu consist of? |
Air inlet, compressor, combustion section, turbine, fuel control, and load control valve |
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What is the function of a typical apu? |
To provide air pressure for engine starting, anti-icing and electrical power for aircraft system operation, both in flight and on the ground |
