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293 Cards in this Set
- Front
- Back
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What procedure should be followed when a valve blow-by is indicated by a hissing sound on a reciprocating engine? |
Perform a cylinder compression test to identify the faulty chamber |
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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 on a twin row radial engine? |
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 the hole for size and condition of the threads. It may be necessary to retap, and use an oversized stud |
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How is a cylinder Barrel check for being out of round? |
A dial indicator can be used to measure at the top of the cylinder and also the skirt. Two readings should be taken at 90 degrees to each other |
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What type of connecting rods are commonly found in a radial engine? |
A master rod and articulated rod assembly. |
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What are the different types of piston rings? |
Compression, oil control and oil scraper rings |
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What is the purpose of oil control rings? |
To regulate the thickness of the oil film on the cylinder wall |
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What type of bearings are in general used in reciprocating engines? |
Plain, ball and roller bearings |
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Where are cracks most likely to be found in a piston? |
In highly stressed areas such as base of the pin bosses, inside at the junction of head and walls, and ringlands. |
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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? |
Absorb the power impulses and reduce the vibration |
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What are the causes for engine sudden stoppage? |
Striking an object or seizure due to internal damage |
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What inspection must be made after a sudden reduction in speed of an engine due to striking an object? |
Check propeller track and check the propeller drive shaft with a dial indicator for misalignment |
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What are some of the precautions to be observed when Engine removal is being accomplished? |
Disconnect the battery, chalk Wheels, install tail stand if needed, turn fuel valves off. |
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What is the indication of a primer that is leaking during operation? |
The engine will not idle properly. |
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What may be the result of incorrect installation of piston rings? |
Excessive oil consumption |
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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? |
Air Inlet, compressor section, combustion section, turbine section, exhaust section and accessories section. |
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What determines the amount of air passing through a turbine engine? |
Compressor speed, forward speed of the aircraft and air density. |
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What are the two principal types of compressors currently used in turbo jet aircraft engines? |
Centrifugal and axial flow compressors |
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How are rotor blades attached to disc type rotors? |
By a blade bulb type root or fir tree type root, dovetail root |
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What are the three types of combustion chamber systems? |
Can, annular, and can 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 of 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 the carbon seals used in turbo jet engines? |
Oil seal in bearing area |
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What is the major difference in turboprop and turbo jet engines? |
The turboprop engine usually has more turbine stages than the turbojet engine. In addition to operating the compressor and accessories, a turboprop engine turbine drives a propeller |
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What is a free turbine engine? |
A turbine in the exhaust system to drive its own power take-off or compressor independently of other turbines |
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What is a turbofan engine? |
Like a turboprop except the propeller blades are replaced with a duct enclosed fan |
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Name an advantage of turbo fan over turbojet. |
Additional thrust without increasing fuel flow |
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What are the functions of axial flow turbine nozzles? |
They prepare the mass air flow for driving the turbine rotor and deflect the gases to a specific angle |
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What is one way of relieving thermal stress on a turbine disc? |
By directing bleed air onto the face of the disc, or by the grooving in the turbine disc. |
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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 turbo jet power? |
Negligible |
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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 turbine efficiency. |
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What functions need to be accomplished in order to prepare an engine for a 100-hour inspection? |
Remove the cowling and clean. |
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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 compression is week? |
Internal cylinder inspection |
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Where are engine operating limitations listed? |
Type certificate data sheets or engine specifications |
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Why is the spectrometric oil analysis program used on turbine engines? |
Under certain conditions and within certain limitations, internal condition of the engine can be evaluated. |
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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? |
A supplemental type certificate can be issued. |
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What airworthiness directives would apply to a specific engine? |
Review airworthiness directives bi-weekly |
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What publication is needed to inspect an engine for Conformity with specifications? |
Engine specifications or type certificate data sheets. |
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What publication is needed to check an engine for normal operation? |
Manufacturers operating manual |
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What is the purpose of a hot section inspection of a turbine engine? |
To determine the mechanical integrity. |
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When is an aircraft engine service bulletin compliance mandatory? |
When it is part of an airworthiness directive |
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How can a turbine engine be leak checked without running the engine? |
Motor engine with starter, ignition and fuel off |
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What publication is needed to perform a turbine engine overspeed inspection? |
Manufacturers Maintenance and Service Publications. |
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What kind of inspection is required after a turbine engine experiences exhaust gas over temperatures? |
Hot section inspection |
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Where do you find a list of Life limited parts? |
Type certificate data sheets or inspection and limitation section of 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? |
180 days |
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When removing and inspecting turbo jet 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 on an aircraft engine? |
Run the aircraft engine 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 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 indicate? |
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, manifold pressure increases. |
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What does a reciprocating engine tachometer indicate? |
Engine crankshaft speed |
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What are turbine engine tachometer gaugees designed to indicate? |
Percent of rotor RPM |
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What is indicated by turbine engine EGT? |
Average temperature measured by individual thermocouples in the exhaust tailpipe. |
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What does turbine engine pressure ratio indicate? |
Trust being developed |
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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 torque meter gauge? |
Torque being developed by the engine is used to indicate the shaft horsepower |
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Where should the thermocouple be installed on a single probe cylinder head temperature system? |
On 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? |
Located 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 resistance of thermocouples and circuits |
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When checking the manifold pressure during run up or operation, in what position would 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, rate of temperature rise, and Flame detectors |
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What will happen to a thermocouple fire warning system on an engine that overheats slowly? |
Nothing, because it takes a fast rate of rise or rapid change to a high temperature to operate |
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What happens to a thermal switch fire protection 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 thermocouple produced voltage |
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What is the minimum number of thermal switch units needed 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 detector? |
Continuous loop system. |
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What is the principle of operation of a kidde continuous loop fire detection system? |
Two wires are embedded in a special ceramic core within an inconel tube. One wire is a ground and the second wire is a hot lead that provides a current when a ceramic core material changes its resistance due to temperature. |
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What is the principle of operation of a fenwal continuous loop fire protection system? |
A single wire is surrounded by ceramic beads in an inconel tube. The resistance is lowered with a 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 HR D fire extinguisher system? |
A fire extinguisher system with a high rate of discharge |
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How is an HR D fire extinguisher 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 extinguisher agents? |
Mechanical or electrical |
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What is the purpose of the discharge cartridge in a turbine engine fire extinguisher system? |
Electrically-operated discharge Cartridge Will release the agent |
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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 and yellow for normal |
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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 a name plate attached to 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 cutout 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? |
3 |
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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, parallel shunt wound, compound wound. |
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How does the voltage regulator control the voltage of an alternator? |
By regulating the voltage output of the DC Exciter |
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What is the probable cause of an engine starter 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 path, prevent static discharge, and protect 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? |
The exhaust turbine bearing |
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What happens to oil at high temperatures? |
Oil becomes thin and oil film is broken |
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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? |
7.5 lb. |
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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 the oil |
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What is the purpose of an oil cooler bypass valve? |
Directs the oil through or around the oil cooler to keep the oil temperature 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 the 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 oil |
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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? |
Oil 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 elements. |
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What is the advantage of multi viscosity oils? |
Wider temperature operating 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 multi pole 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 on the compression stroke. |
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Where is the E Gap position in a Magneto? |
A few degrees Beyond magnetic neutral |
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What is the purpose of the condenser/ capacitor in a Magneto? |
Prevents arcing at the points, and AIDS in the collapsing of the magnetic field. |
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What happens when a magnetic rotor is in the E Gap position and the primary breaker points open? |
Stops flow of current in the primary circuit and a high rate of flux change occurs in the core, inducing a pulse of high voltage in the secondary. |
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What are two purposes of a high-tension ignition harness? |
Supports the wires and protects them from damage by engine heat, vibration, or weather. And serves as a conductor for stray magnetic fields and cuts down the electrical interference. |
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When an ignition switch is off, what is the condition of the ground circuit? |
The circuit to ground is completed |
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What is the purpose of the 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 a short high-tension lead. |
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Which Magneto is grounded when the Magneto switch is selected to the right Magneto? |
Left Magneto 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 are the three events required to fire a spark plug in a cylinder when its piston is in the prescribed position? |
Magneto is in the e gap position, breaker points 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 disc. |
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What factors are involved in the Magneto internal timing? |
Egap position and distributor rotor position. |
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What is the most common type ignition system used on turbine engines? |
Capacitor. |
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When are turbine engine ignition systems used? |
For starting, or when in Flight conditions call for flameout protection. |
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What type of igniter plugs are used in turbine engines? |
Annular Gap type and constrained Gap type |
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What is the purpose of water injection? |
Enables more power to be obtained from the engine at takeoff power. |
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What happens to fuel air mixture in a reciprocating engine when the water injection system is operated? |
The engine can be operated on best power mixture and manifold pressure increased. |
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What are the two types of carburetors most commonly used on small reciprocating engines? |
Float type carburetor and pressure type carburetors |
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What is the function of a mixture control on float type carburetor? |
Controlling fuel air mixtures |
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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 in the Venturi |
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When does a carburetor economizer system needle valve open? |
Above approximately 60 to 70% of rated power. |
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What is the purpose of a carburetor economizer system? |
For additional fuel at high powers for cooling the engine to prevent detonation |
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Where does a pressure injection carburetor obtain fuel pressure? |
Engine driven fuel pump. |
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What operates an automatic mixture control? |
A sealed Bellows that contracts or expands with a change in atmospheric pressure |
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What position of a pressure injection carburetor manual mixture control would stop engine operation? |
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 problem is caused by excessively rich mixture 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 the function of turbine engine fuel control units? |
Automatically satisfies fuel requirement of the engine. |
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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, and compressor discharge pressure and burner pressure and either EGT or TIT |
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What two sources are used in turbine engine fuel systems for fuel Heat? |
Bleed air and engine lubrication oil |
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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 fuel 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 bypasses excess fuel |
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What type of fuel pump varies the amount of field discharge with any speed? |
Variable displacement pump. |
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What is the purpose of a pressurization and dump valve? |
Provide positive cut off 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 type pump. |
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What is the purpose of fuel booster pumps? |
To supply engine-driven fuel pumps |
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What is commonly used type of fuel booster pump? |
Centrifugal type |
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What is the cause of vapor lock? |
Low fuel pressure, high fuel temperature and excessive fuel turbulence |
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Why is vapor lock serious? |
The fuel flow may be completely blocked |
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What is the purpose of Main Line fuel strainers? |
To keep foreign matter out of the carburetor |
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What are the purposes of fuel selector valves? |
Provides a means for shutting off fuel flow, tank an engine selections, cross-feed, 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 in turbine fuel filters? |
Air to liquid or liquid to liquid Heat exchangers. |
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What is a duplex fuel nozzle used in turbine engines? |
A fuel nozzle with two spray patterns. |
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What do you look for during an 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, air scoop, and 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 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 deicing 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 two types of supercharged induction systems? |
Internally driven and externally driven. |
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What is the function of a distribution impeller? |
Driven by the engine crankshaft, it does not increase air pressure, but as the fuel goblets strike the impeller it will create a more homogeneous mixture |
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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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Where does an externally driven supercharger derive its power? |
Energy of engine exhaust gases directed against turbine blades. |
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What is the function of a Turbocharger wastegate? |
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 wastegate will not close? |
Aircraft me not reach critical altitude |
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What could be the probable cause of a turbocharged engine that surges? |
Wastegate or controller malfunction. |
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What is used on Many turbocharged engines for the wastegate actuator power? |
Oil pressure |
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What engine power indication will occur when carburetor heat is applied to an operating engine? |
A slight loss of 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 is bypassed or 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 the behavior of combustion, weakens and shortens the life of engine parts, and impairs lubrication. |
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What type of air cooled cylinder construction increases the effect of surface area for cooling? |
Cooling fins are used |
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What is engine Cooling? |
Transferring heat from 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're designed to direct airflow over the cylinder and engine accessories for power plant 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. |
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What type of power is used to operate cowl flaps? |
Manual, electrical, or hydraulic. |
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How are accessories cooled? |
Blast tubes are built into baffles to direct cooling air past accessories. |
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Where should cowl flaps be positioned during ground operations? |
Fully open |
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What information must be consulted prior to reprofiling a cooling fin? |
Manufacturers service Publications |
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What are the functions of engine cowling? |
Streamlines 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 baffle stream. |
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Why is cow flap adjustment important? |
The movement must be within tolerance to keep cylinder head temperature 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. |
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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? |
Structure, Fuel and oil |
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What type of material is used to make turbine engine insulation blankets? |
Aluminum, glass fiber, 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? |
Provide protection against potentially destructive action of exhaust gases |
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What are the two types of reciprocating engine exhaust systems? |
The short stack system and The Collector system |
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What type of exhaust system is used on turbo supercharged engines? |
The Collector system |
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What type exhaust system is generally used on non supercharged low-powered engines? |
The short openstack 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 |
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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's 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 wastegate sticking? |
Coke deposits or carbon buildup |
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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 |
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What are exhaust system Coke deposits? |
Excessive carbon buildup |
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What would happen to turbine engine performance if the exhaust nozzle shape was 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? |
Aid in decelerating an aircraft after landing |
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What is the function of the thermocouple probes in a turbine exhaust tail pipe? |
Measure exhaust gas temperature |
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How do you determine the repairability of a damaged propeller blade? |
Reference the manufacturer's maintenance manual |
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What is the purpose of propellers? |
The blades produce forces that create thrust to pull or push the airplane through the air |
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What is a fixed pitch propeller? |
The blade angle is built into the propeller and cannot be changed |
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What type of Blade angle change will occur on a propeller that is pitch controlled by a propeller Governor during a constant power dive? |
The blade angle increases to overcome over-speeding |
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Other than maintaining constant speed, what are two actions of some controllable propeller systems? |
Reverse and Feathering |
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What is the purpose of metal tipping fastened to a wood 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 propeller? |
Blade tracking and low blade angle setting |
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What is blade tracking? |
Determining the positions of the tips 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 we used to clean aluminum propeller blades and hubs? |
The propeller should be cleaned in accordance with the manufacturer's recommendations |
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What positions of a 2 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 |
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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? |
Propeller will feather |
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What may be adjusted in a hydromatic propeller system to increase or decrease RPM? |
Propeller governor |
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What types of systems are used for propeller ice control? |
Fluid alcohol and electrical |
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What type of non-destructive 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 turbo propeller system? |
mechanically actuates a linkage in the propeller control which results in increased blade angle until propeller is not driving the engine. |
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What is the purpose of an oil accumulator connected to a propeller governor? |
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? |
Main aircraft fuel tank |
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What speed does an APU operate at? |
At a very high RPM, which is controlled by the Apu fuel control and speed sensitive switches if over-speeding 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 shut down? |
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? |
Approximately 3 to 4 minutes |
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How is the operational speed of an APU controlled? |
Apu fuel control adjusts the speed by adjusting the fuel flow |
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Name at least two uses for an APU. |
Engine start, aircraft ground operation, anti-icing |
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What type of operational practices can cause thermal shock to an APU? |
Not following the prescribed cooling down cycle |
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What powers the variable Inlet guide vanes on an APU? |
Fuel pressure from the fuel control system |
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What does a typical Apu consist of? |
Air Inlet, compressor, combustion, 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 |
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Where are most APUs located in modern jet Transport Aircraft? |
In the tail cone of the fuselage |
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What is the function of an APU? |
An APU provides electric power and compressed air when the main engines are not operating |
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What are two sources of compressed air from the APU? |
From bleed air from the Apu compressor, or from a load compressor driven by a free turbine in the engine |
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Where in maintenance information based on the ATA-100 system would you find instructions for inspecting and servicing the engine of an Airborne APU? |
In section 49 20 |
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How is most of the troubleshooting done for a modern APU? |
By the fault codes generated by the FADEC |
