Aviation Mechanic Powerplant Oral

Front 1

What procedure should be followed when valve blow-by is indicated by a hissing sound on a reciprocating engine?

Back 1

Perform a cylinder compression test to identify the faulty chamber.

Front 2

What is the running valve clearance on engines equipped with hydraulic valve lifters?

Back 2

Zero

Front 3

What type of check can be made to locate a cold cylinder in a twin row radial engine?

Back 3

A cold cylinder check

Front 4

What factors about the condition of an engine can be learned by studying the results of a compression check?

Back 4

It determines if the valves, piston rings, and pistons are adequately sealing.

Front 5

What should be done to repair a loose stud in an engine crankcase?

Back 5

Remove the loose stud, check the hole for size and condition of threads. Retap if needed.

Front 6

How is a cylinder barrel checked for being out of round?

Back 6

A dial indicator can be used to measure the top and skirt of the cylinder. Two readings should be taken 90 degrees to each other.

Front 7

What type of connecting rods are commonly found in a radial engine?

Back 7

1. master rod

2. articulated rod assy

Front 8

What are the different types of piston rings?

Back 8

1.Compression

2. oil control

3. oil scraper rings

Front 9

What is the purpose of oil control rings?

Back 9

To regulate the thickness of the oil film on the cylinder wall.

Front 10

What type of bearings are in general use in reciprocating engines?

Back 10

1. Plain

2. Ball

3. Roller bearings

Front 11

Where are cracks most likely to be found in a piston?

Back 11

Highly stressed areas such as base of pin bosses, inside at the junction of head and walls, and ring lands.

Front 12

What are the different types of reciprocating engines?

Back 12

1. In-line

2. opposed

3. v-type

4. radial

Front 13

What is the purpose of valve overlap?

Back 13

Permits better volumetric efficiency and lowers the cylinder operating temperature.

Front 14

What is the purpose of crankshaft dynamic dampers?

Back 14

Absorb the power impulses and reduce the vibration.

Front 15

What are the causes of engine sudden stoppage?

Back 15

Striking an object or seizure due to internal damage.

Front 16

What inspection must be made after a sudden reduction in speed of an engine due to striking an object?

Back 16

1. Check propeller track

2. check propeller drive shaft with a dial indicator for misalignment

Front 17

What are some of the precautions to be observed when engine removal is being accomplished?

Back 17

1. d/c battery
2. chock wheels

3. install tail stand if needed

4. turn off fuel valves

Front 18

What is the indication of a primer that is leaking during operation?

Back 18

The engine will not idle properly.

Front 19

What may be the result of incorrect installation of piston rings?

Back 19

Excessive oil consumption

Front 20

What is the indication of an induction leak?

Back 20

Low power or uneven running

Front 21

What are the major components of a typical gas turbine engine?

Back 21

1. Air inlet

2. compressor section

3. combustion section

4. turbine section

5. exhaust section

6. accessory section

Front 22

What determines the amount of air passing through a turbine engine?

Back 22

1. compressor speed

2. forward speed of the aircraft

3. air density

Front 23

What are the 2 prinicpal types of compressors currently used in turbojet aircraft engines?

Back 23

1. Centrifugal

2. axial flow compressors

Front 24

How are rotor blades attached to disk type rotors?

Back 24

1. Blade bulb type root

2. fir tree type root

Front 25

What are the types of combustion chamber systems?

Back 25

1. Can

2. Annular

3. Can-annular

4. Reverse-flow annular

Front 26

What is the purpose of the interconnect tubes attached between can-type combustion chambers?

Back 26

For flame propagation during starting

Front 27

What prevents burning of combustion chambers?

Back 27

Cooling air along the inside wall of the liner

Front 28

What is a split compressor system?

Back 28

Two concentric shafts joining the turbine stages to their compressors. Also called dual or twin spool compressors, these are connected to the turbine section with two rotor shafts, one inside the other.

Front 29

Where are carbon seals used in turbojet engines?

Back 29

Oil seal in bearing area

Front 30

What is the major difference in turboprop and turbojet engines?

Back 30

1. turboprop has more turbine stages than turbojet

2. turboprop drives a propeller

Front 31

What is a free turbine engine?

Back 31

A turbine in the exhaust system to drive its own power take-off or compressor independently of other turbines.

Front 32

What is a turbofan engine?

Back 32

Similar to turboprop except propeller blades are replaced with a duct enclosed fan.

Front 33

Name an advantage of turbofan over turbojet?

Back 33

A turbofan engine uses a fan to bypass some air around the engine core and to provide thrust. Advantage is additional thrust without increasing fuel flow

Front 34

What are functions of axial flow turbine nozzles?

Back 34

Prepare mass air flow for driving the turbine rotor and deflect the gases to a specific angle.

Front 35

What is one way of relieving thermal stress on a turbine disk?

Back 35

By directing bleed air on to the face of the disk, or by grooving in the turbine disk.

Front 36

What type of compressor blade damage may be found when inspecting compressor blades?

Back 36

1. dents

2. galling

3. pitting

4. cracks

5. scratches

6. burrs

7. burns

8. gouges

Front 37

What is used to mark combustion system parts for disassembly?

Back 37

Layout dye or chalk

Front 38

What is the effect of relative humidity on turbojet power?

Back 38

Negligible

Front 39

What may be the indications if a turbojet engine is out of trim?

Back 39

Engine has high exhaust gas temp at engine pressure for takeoff power.

Front 40

What would be the possible cause be for a turbojet engine with high EGT, low RPM, and high fuel flow at all engine pressure ratio settings?

Back 40

Possible turbine damage or loss of efficiency.

Front 41

What functions need to be accomplished in order to prepare an engine for a 100hour inspection?

Back 41

Remove cowling and clean engine

Front 42

How can a mechanic visually ID engines?

Back 42

By the engine data plate

Front 43

What may be used as guide for 100 hour inspections on engines?

Back 43

FAR 43 appendix D and Manufacturer's maintenance manual

Front 44

What additional inspection must be performed if a cylinder compression is weak?

Back 44

Internal cylinder inspection

Front 45

Where are engine operating limitations listed?

Back 45

Type certificate data sheets or engine specifications.

Front 46

Why is the spectrometric oil analysis used on turbine engines?

Back 46

Internal condition of the engine can be evaluated.

Front 47

What type of FAA approval is required when a change to an engine design is not enough to require a new type certificate?

Back 47

STC (supplemental type certificate)

Front 48

What ADs would apply to a specific engine?

Back 48

Review ADs and biweekly

Front 49

What publication is needed to inspect an engine for conformity with specifications?

Back 49

Type certificate data sheet or engine specifications.

Front 50

Why publication is needed to check an engine for normal operation?

Back 50

Manufacturers operating manual

Front 51

What is the purpose of a hot section inspection of a turbine aircraft?

Back 51

To determine the mechanical integrity.

Front 52

When is an aircraft engine service bulletin compliance mandatory?

Back 52

When it is part of an AD or when compliance is part of the approved specifications for a commercial or air carrier operator. Or at time of overhaul if required.

Front 53

How can a turbine engine be leak checked without running the engine?

Back 53

Dry motor

Front 54

What publication is needed to perform a turbine engine over speed inspection?

Back 54

Manufacturers maintenance manual and service publications.

Front 55

What kind of inspection is required after a turbine engine experiences exhaust gas overtemperatures?

Back 55

Hot section inspection

Front 56

Where do you find a list of life limited parts?

Back 56

Type certificate data sheets or inspection section of Maintenance manual.

Front 57

What criteria is used to determine the replacement of life limited turbine engine components?

Back 57

Cycles, hours, and calendar time.

Front 58

How often should the humidity indicator be inspected on metal containers storing engines under normal conditions?

Back 58

180 days

Front 59

When removing and inspecting turbine blades, why is it important that they be installed in the same location?

Back 59

To maintain balance of the turbine wheel.

Front 60

Prior to returning a reciprocating engine to service after a 100-hour inspection, what operational checks must be performed?

Back 60

Check the power output(static and idle rpm), check magnetos , fuel and oil pressure check, cylinder and oil temp check.

Front 61

In reference to a reciprocating engine, where is a fuel flow indicating system generally connected in an engine fuel flow system.

Back 61

Between the engine fuel pump and carburetor.

Front 62

What basic components are used in engine fuel flow system?

Back 62

Transmitter and indicator

Front 63

What type of readout is indicated on a fuel flow system?

Back 63

Amount of fuel flow in pounds/gallons per hour.

Front 64

What is the fuel pressure range of a float type carburetor?

Back 64

3-5 psi.

Front 65

What is the reason for monitoring fuel flow?

Back 65

Fuel flow is an indication of fuel consumption and engine performance.

Front 66

What does a manifold pressure gauge indicate?

Back 66

Absolute manifold pressure in inches of mercury.

Front 67

What directly controls manifold pressure?

Back 67

Engine rpm and throttle opening

Front 68

On an engine equipped with a fixed pitch propeller, what is the relationship between manifold pressure and RPM?

Back 68

As rpm increases, manifold pressure increases.

Front 69

What does a reciprocating engine tachometer indicate?

Back 69

Crankshaft speed (Engine RPM)

Front 70

What are turbine engine tachometer gauges designed to indicate?

Back 70

Percent of rotor RPM.

Front 71

What is indicated by turbine engine EGT?

Back 71

Average temp in the exhaust tailpipe.

Front 72

What does turbine engine pressure ratio indicate?

Back 72

Thrust being developed.

Front 73

What pressures are measured to obtain engine pressure ratio?

Back 73

Total inlet pressure and total turbine discharge pressure.

Front 74

What is indicated by a turboprop torquemeter gauge?

Back 74

Torque being developed by the engine is used to indicate shaft horsepower.

Front 75

Where should the thermocouple be installed on a single probe cylinder head temp system?

Back 75

On the hottest cylinder.

Front 76

What is the electrical source for cylinder head temperature systems?

Back 76

Thermocouple

Front 77

Where is the location of the carburetor air temperature bulb?

Back 77

Located in the ram air intake duct.

Front 78

What is the possible cause when oil pressure drops off severely, oil supply remains full, and oil temp is normal?

Back 78

Oil pressure transmitter or indicator malfunction

Front 79

How can a turbine EGT system be checked without running the system?

Back 79

By checking resistance of thermocouples and circuits.

Front 80

When checking the manifold pressure during run up or operation, in what position would the prop control be set?

Back 80

High rpm/low pitch

Front 81

Name two types of fire detector systems used for engine fire protection.

Back 81

1. overheat

2. rate of rise

3. flame detectors

Front 82

What will happen to a thermocouple fire warning system on an engine that overheats slowly?

Back 82

Nothing, it takes a fast rate of rise or rapid change to operate.

Front 83

What happens to a thermal switch fire protection system when it is heated enough to operate?

Back 83

An electrical ground is provided for a red warning light in the cockpit when heated past a certain temperature.

Front 84

What electrical power is needed for a thermocouple fire protection system?

Back 84

Aircraft electrical system and thermocouple produced voltage.

Front 85

What is the minimum number of thermal switch units needed for a thermal switch fire protection system?

Back 85

At least one

Front 86

What is a type of fire protection system that covers more area than a spot type temperature detector?

Back 86

Continuous loop system

Front 87

What is the principle of operation of a kidde continuous loop fire protection system?

Back 87

Two wires are imbedded 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 the ceramic core changes its resistance due to temperature.

Front 88

What is the principle of operation of a fenwall continuous loop fire protection system?

Back 88

A single wire is surrounded by ceramic beads in an inconel tube. The resistance is lowered with a temperature rise.

Front 89

What is the purpose of a fixed fire extinguishing system?

Back 89

To discharge an inert agent that will not support combustion or reduce temperatures to below ignition point.

Front 90

What methods are used to distribute fire extinguishing agents?

Back 90

Perforated tubing or discharge nozzles.

Front 91

What is an HRD fire extinguisher system?

Back 91

High rate of discharge system

Front 92

How is an HRD fire extinguisher agent distributed?

Back 92

High pressure open end tubes

Front 93

How long does it take to discharge an HRD agent?

Back 93

1 to 2 seconds

Front 94

What fire extinguishing agents are used for aircraft engines?

Back 94

1. Carbon dioxide

2. Freon

3. Halon

Front 95

What methods are used for discharging fire extinguisher agents?

Back 95

Mechanical or electrical

Front 96

What is the purpose of the discharge cartridge in a turbine engine fire extinguisher system?

Back 96

Electrically operated discharge cartridge will release the agent.

Front 97

What is the purpose of the red and yellow discharge plugs associated with a turbine engine fire extinguisher system?

Back 97

Red for thermal and yellow for normal discharge

Front 98

What will happen to an engine fire sensing loop when the sensing loop is excessively kinked or bent?

Back 98

False fire warning light or inop system

Front 99

What two items in a turbine engine fire extinguisher system indicate low agent pressure in a container.

Back 99

Low pressure warning light and pressure gauge.

Front 100

What is the purpose of a pressure gauge in a fire extinguishing system?

Back 100

Indicates pressure within the container. To check for correct pressure there is a pressure-temperature chart.

Front 101

Where is generator rating and performance data located?

Back 101

Stamped on a nameplate attached to the generator

Front 102

How are DC generator terminals marked?

Back 102

A, B, and E.

Front 103

What is used to control DC generator voltage?

Back 103

By varying field current strength.

Front 104

What three components make up a vibrator-type DC pegulator in an electrical system?

Back 104

1. Current limiter

2. Reverse current cut out relay

3. Voltage regulators

Front 105

Why are multigenerator systems paralleled?

Back 105

Each generator must share the load.

Front 106

How many phases are used in most aircraft ac alternator systems?

Back 106

Three

Front 107

What determines the frequency of an alternator output?

Back 107

The speed of rotation of the rotor and the number of poles

Front 108

What are 3 types of generators used on aircraft engines?

Back 108

1. Series wound

2. Parallel (shunt) wound

3. Compound wound

Front 109

How does the voltage regulator control the voltage of an alternator?

Back 109

By regulating the voltage output of the d.c. exciter.

Front 110

What is the probable cause of an engine started that operates but does not turn the crankshaft?

Back 110

Starter not engaging due to damaged pinion or crankshaft.

Front 111

What is the purpose of the bonding wires on a powerplant installation?

Back 111

1. provide current return paths

2. prevent static discharge

3. protect aircraft and personnel from static discharge

Front 112

What is the primary purpose of an aircraft reciprocating engine lubricant?

Back 112

Reduce friction between moving parts and remove heat.

Front 113

What is one of the most important properties an aircraft reciprocating engine oil must possess?

Back 113

Viscosity

Front 114

What is the most critical lubrication point in a gas turbine engine?

Back 114

The exhaust turbine bearing.

Front 115

What happens to oil at high temps?

Back 115

Oil becomes thin and the oil film is broken.

Front 116

How much does aircraft engine oil weigh per gallon?

Back 116

7.2 pounds

Front 117

Why must reciprocating engines use an oil with high viscosity?

Back 117

1. high operating temps

2. high bearing pressures

3. large operating clearances

Front 118

Why is an oil tank required to have expansion space?

Back 118

To provide for expansion and foaming of the oil.

Front 119

What is the purpose of an oil cooler bypass valve?

Back 119

Directs the oil through or around the oil cooler to keep the oil temperature within operating limits.

Front 120

What does the oil temperature bulb usually sense?

Back 120

Engine oil inlet temperature

Front 121

What does the presence of metal particles in an engine oil screen indicate?

Back 121

Possible engine internal failure

Front 122

What are two areas of an engine oil system where oil screens may be located?

Back 122

1. oil pressure system (main filter)

2. scavenge system

3. At the oil jet (last chance)

Front 123

What are some oil contaminants?

Back 123

1. Gasoline

2. moisture

3. acids

4. metal particles

5. dirt

6. carbon

Front 124

What type of oil is usually used in turbine engine oil systems?

Back 124

Synthetic

Front 125

What could be the cause of excessive oil consumption without evidence of oil leaks?

Back 125

Worn or broken piston rings

Front 126

What would be an indication of inadequate oil supply?

Back 126

Low oil pressure and high oil temperature

Front 127

What factors must be considered in determining proper grade of oil?

Back 127

1. Operating load and temperature

2. rotational speeds

Front 128

What would be an indication of an obstruction in oil cooler passages?

Back 128

High oil temp

Front 129

What could cause oil foaming?

Back 129

1. diluted oil

2. contaminated oil

3. oil level being too high

Front 130

What are two types of turbine engine oil coolers?

Back 130

1. Air cooled

2. fuel cooled

Front 131

What controls oil pressure in a gear type oil pressure pump?

Back 131

Oil pressure relief valve

Front 132

Why is it necessary to cut open a can cartridge type oil filter after removal?

Back 132

To inspect filter element

Front 133

What is the advantage of multi-viscosity oils?

Back 133

Wider temperature operating ranges

Front 134

What is the purpose/function of a magneto?

Back 134

A magneto produces a high voltage which forces a spark to arc across a spark plug gap.

Front 135

What are the 3 major circuits of a high tension magneto system?

Back 135

1. Magnetic

2. primary

3. Secondary

Front 136

What are the components of a high tension magnetic circuit?

Back 136

Permanent multi pole rotating magnet, soft iron core and pole shoes

Front 137

In terms of the engine crankshaft degrees, when does the ignition event occur?

Back 137

A specified number of degrees before top dead center on the compression stroke.

Front 138

Where is the e-gap angle/position in a magneto?

Back 138

A point a few degrees beyond the neutral position of a rotating magnet where maximum magnetic field stress exists.

Front 139

What is the purpose of the condenser/capacitor in a magneto?

Back 139

Prevents arcing at the points, and aids in the collapsing of the magnetic field.

Front 140

How does a magneto produce the high voltage required to fire a spark plug?

Back 140

In the rotation cycle, when the magnetic rotor is in the e-gap position, the primary points open, which interrupts the current flow in the primary circuit causing a (high rate of) flux change in the core, and inducing a pulse of high voltage in the secondary coil.

Front 141

What are two purposes of a high tension ignition harness?

Back 141

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.

Front 142

When an ignition switch is off, what is the condition of the ground circuit?

Back 142

The circuit to ground is completed.

Front 143

How can you identify a low tension ignition system?

Back 143

By the presence of an external transformer coil and a short high tension lead.

Front 144

What is the purpose of the dual magneto ignition system?

Back 144

System redundancy (safety factor) and improved combustion efficiency.

Front 145

Which magneto is grounded when the magneto switch is selected to the right magneto?

Back 145

Left magneto is grounded.

Front 146

What is meant by spark plug reach?

Back 146

The distance from the gasket surface to the end of the threaded area.

Front 147

What are the three events required to fire a spark plug in a cylinder when its piston is in the prescribed position?

Back 147

1. Magneto is in the e-gap position

2. breaker points opening

3. distributor electrically aligned with the cylinder

Front 148

What is the purpose of a magneto timing light?

Back 148

Used for both internal mag timing and magneto to engine timing. It determines the exact instant that the magneto points open.

Front 149

How can top dead center of a piston be located?

Back 149

A piston indicator or timing disk.

Front 150

What factors are involved in the magneto internal timing?

Back 150

E-gap position and distributor rotor position.

Front 151

What is the most common type ignition system used on turbine engines?

Back 151

Capacitor

Front 152

What type of igniter plugs are used in turbine engines?

Back 152

1. Annular-gap

2. constrained gap

Front 153

When are turbine engine ignition systems used?

Back 153

For starting, or for flame-out protection in flight.

Front 154

What is the purpose of fuel injection?

Back 154

Enables more power to be obtained from the engine at takeoff power.

Front 155

What happens to fuel/air mixture in a reciprocating engine when the fuel injection system is operated?

Back 155

The engine can be operated on best power mixture and manifold pressure increased.

Front 156

What are two types of carburetors most commonly used on small reciprocating engines?

Back 156

Float-type carburetors and pressure type

Front 157

What is the function of a mixture control on float-type carburetors?

Back 157

Controlling fuel/air mixtures.

Front 158

What is the action of a float type carburetor accelerating system when the throttle is opened with a quick action?

Back 158

A charge of fuel will enrich the mixture in the venturi.

Front 159

When does a carburetor economizer system needle valve open?

Back 159

Above approximately 60-70 percent of rated power.

Front 160

What is the purpose of a carburetor economizer system?

Back 160

For additional fuel at high powers for cooling the engine to prevent detonation.

Front 161

Where does a pressure injection carburetor obtain fuel pressure?

Back 161

Engine driven fuel pump.

Front 162

What operates an automatic mixture control?

Back 162

A sealed bellows that contracts or expands with change in atmospheric pressure.

Front 163

What position of a pressure injection carburetor manual mixture control would stop engine operation?

Back 163

Idle cutoff position

Front 164

What are the operating principles of direct fuel injection systems?

Back 164

Measures engine air consumption, uses air flow forces to control fuel flow, and supplies fuel from an injection pump directly to each cylinder

Front 165

Why should a pressure type carburetor be filled with fuel and allowed to soak for 8 hours prior to installation?

Back 165

To soak the diaphragms and render them pliable to the degree they were when the unit was originally calibrated.

Front 166

What problem is caused by excessively rich mixture at idle?

Back 166

Spark plug fouling

Front 167

What is the indication of rpm when an idle mixture is set correctly, and the mixture control is placed to the idle cutoff position?

Back 167

A slight rise in RPM prior to decreasing.

Front 168

Why should engine rpm be accelerated periodically when making carburetor adjustments?

Back 168

To clear the engine.

Front 169

What is the function of turbine engine fuel control units?

Back 169

Automatically meters fuel to the engine.

Front 170

What are the two basic types of turbine engine fuel control units?

Back 170

1. Hydromechanical

2. electronic

Front 171

What are some of the engine variables detected by a turbine engine fuel control unit?

Back 171

1. Power lever position

2. Engine rpm

3. Compressor inlet temperature

4. Compressor inlet pressure

5. Compressor discharge pressure

6. Burner pressure

Front 172

What two sources are used in turbine engine fuel systems for fuel heat?

Back 172

1. Bleed air

2. Engine oil

Front 173

How is fuel delivered to a turbine engine burner section?

Back 173

From the fuel control to one or more spray nozzles.

Front 174

What are the most common types of fuel metering systems used on small reciprocating engines?

Back 174

1. Float type carburetors

2. Pressure injection carburetors

3. Direct fuel injection

Front 175

What is the purpose of engine driven fuel pumps?

Back 175

To deliver a continuous supply of fuel at the proper pressure While the engine is running.

Front 176

What are two categories of turbine-engine fuel pumps?

Back 176

1. Constant displacement

2. Variable displacement

Front 177

A gear type pump is classified in what category?

Back 177

Constant displacement pump

Front 178

What protects an engine from fuel pump seizure?

Back 178

Shear section of the shaft

Front 179

What happens to excess fuel not required by an engine in a constant displacement pump?

Back 179

The pressure relief valve bypasses excess fuel.

Front 180

What type of fuel pump varies the amount of fuel discharged with any speed?

Back 180

Variable displacement pump

Front 181

What is the purpose of a pressurization and dump valve?

Back 181

The pressurizing portion provides primary and secondary fuel flow to dual-line duplex fuel nozzles, and the dump portion allows fuel to drain from the manifolds after engine shutdown.

Front 182

What type of engine driven fuel pump is widely used other than gear and piston pumps?

Back 182

Rotary vane type pump

Front 183

What is the purpose of fuel boost pumps?

Back 183

They supply pressurized fuel to the fuel pump, which helps prevent vapor lock and cavitation.

Front 184

What is commonly used type of fuel boost pump?

Back 184

Centrifugal type

Front 185

What is the cause of vapor lock?

Back 185

Low fuel pressure, high fuel temp, and excessive fuel turbulence

Front 186

Why is vapor lock serious?

Back 186

The fuel flow may be completely blocked.

Front 187

What is the purpose of main line fuel strainers?

Back 187

To keep foreign matter out of the carburetor.

Front 188

What are the purposes of fuel selector valves?

Back 188

1. Provides a means for shutting off fuel flow

2. tank and engine selections

3. crossfeed and fuel transfer

Front 189

What unit in a turbine engine fuel system is susceptible to the formation of ice?

Back 189

Fuel filter

Front 190

What is a safety feature in an engine fuel system micron filter?

Back 190

A bypass valve

Front 191

What method is used to prevent ice in turbine fuel filters?

Back 191

Air to liquid or liquid to liquid heat exchangers

Front 192

What is a duplex fuel nozzle used in turbine engines?

Back 192

A fuel nozzle with two spray patterns.

Front 193

What do you look for during external inspection of an engine driven fuel pump?

Back 193

Leaks and security of mounting

Front 194

What are the three units in a reciprocating engine induction system?

Back 194

1. carburetor

2. airscoop

3. intake manifold

Front 195

What is the effect on engine performance when induction system icing occurs?

Back 195

Engine power loss and erratic operation

Front 196

What are the three classifications of ice?

Back 196

1. Impact ice

2. Fuel evaporation

3. Throttle ice

Front 197

What method is used to prevent induction system ice?

Back 197

Raising the temp of induction air with a pre-heater.

Front 198

How is ice cleared on some aircraft if carburetor heat is too low to clear the ice?

Back 198

Alcohol is used as a de-icing agent.

Front 199

When is carburetor throttle ice likely to form due to throttle position?

Back 199

When the throttle is near the closed position because of a bigger surface area for ice to form.

Front 200

What are two types of supercharged induction systems?

Back 200

Internally and externally driven

Front 201

What is the function of a distribution impeller?

Back 201

Driven by the engine crankshaft, does not increase air pressure, creates a more homgeneous mixture as fuel goblets strike the impeller.

Front 202

How does an internally driven supercharger driven by the engine crankshaft boost air pressure?

Back 202

A high speed impeller compresses the fuel air mixture after it leaves the carburetor.

Front 203

Where does an externally driven supercharger derive its power?

Back 203

Energy of engine exhaust gases directed against turbine blades.

Front 204

What is the function of a turbocharger waste gate?

Back 204

It controls the amount of exhaust gas either into or around the turbocharger, thus controlling the boot pressure of the turbocharger.

Front 205

What may be the indication of leaking intake pipes?

Back 205

Engine runs rough at low rpm.

Front 206

What may be the indication of an induction system obstruction?

Back 206

Engine fails to start or power is low.

Front 207

What may be the indication if a turbocharger waste gate will not close?

Back 207

Aircraft may not reach critical altitude.

Front 208

What could be the probable cause of a turbocharged engine that surges?

Back 208

Waste gate or controller malfunction

Front 209

What is used on many turbocharged engines for the waste gate actuator power?

Back 209

Oil pressure

Front 210

What engine power indication will occur when carburetor heat is applied to an operating engine?

Back 210

A slight loss in engine power

Front 211

What is the danger of applying carburetor heat with high engine power?

Back 211

Detonation

Front 212

What happens to the induction air supply in a filtered air induction system when the filter becomes restricted?

Back 212

The filter is bypassed or loss of power.

Front 213

What is the indication of a dirty air inlet filter?

Back 213

Low power

Front 214

What are the main reasons that excessive heat is undesirable in any air cooled reciprocating engine?

Back 214

1. affects behavior of combustion

2. shortens the life of engine parts

3. impairs lubrication

Front 215

What type of air cooled cylinder construction increases the effective surface area for cooling?

Back 215

Cooling fins

Front 216

What is engine cooling?

Back 216

Transferring heat from engine cylinders to the air.

Front 217

What should be done to cylinders with excessive cooling fin area broken off?

Back 217

Replace the cylinder

Front 218

What is the principle function of engine cowling and baffles?

Back 218

Direct air flow over the cylinders and accessories for engine cooling

Front 219

What method is used to control air flow through the cooling area of an engine?

Back 219

Cowl flaps

Front 220

What is an augmentor cooling system?

Back 220

An outer tube is placed over the exiting exhaust gas and creates a venturi effect that draws more airflow over the engine, thus providing additional cooling.

Front 221

What type of power is used to operate cowl flaps?

Back 221

1. mechanical

2. electrical

3. hydraulic

Front 222

How are accessories cooled?

Back 222

Blast tubes are built into baffles to direct cooling air past the accessories.

Front 223

Where should cowl flaps be positioned during ground operations.

Back 223

Fully open

Front 224

What information must be consulted prior to re-profiling a cooling fin?

Back 224

Manufacturers maint manual

Front 225

What are the functions of engine cowling?

Back 225

Streamlines engine to reduce drag and controls air flow past cylinders.

Front 226

What is the purpose of cowl air seal?

Back 226

Forces air to circulate around and through baffle stream.

Front 227

Why is cowl flap adjustment important?

Back 227

The movement must be within tolerance to keep cylinder head temperature within allowable limits.

Front 228

Where must cooling air flow to cool a turbine engine.

Back 228

Through the inside of the engine.

Front 229

What areas of a turbine engine are cooled by air passing through the engine?

Back 229

Combustion chamber and turbine

Front 230

What is the source of bleed air vented to turbine engine bearings and other parts in some engines?

Back 230

Engine compressor

Front 231

Other than cooling air, what method is used to cool components and structures adjacent to turbine engines?

Back 231

Insulation blankets

Front 232

What does turbine engine insulation protect from heat?

Back 232

Structure, fuel and oil.

Front 233

What type of material is used to make turbine engine insulation blankets?

Back 233

1. aluminum

2. glass fiber

3. stainless steel

Front 234

How are high temp noxious gases disposed of in a reciprocating engine?

Back 234

Engine exhaust system

Front 235

What is a function of an exhaust system?

Back 235

Provide protection against potentially destructive action of exhaust gases.

Front 236

What are two types of reciprocating engine exhaust systems?

Back 236

short stack and collector system

Front 237

What type of exhaust system is used on turbosupercharged engines?

Back 237

collector system

Front 238

What type of exhaust system is generally used on non-supercharged low powered engines?

Back 238

The short (open) stack system

Front 239

What exhaust system raises engine exhaust back pressure?

Back 239

collector system

Front 240

Why is an exhaust system failure considered a severe hazard?

Back 240

Carbon monoxide poisoning, loss of power or fire.

Front 241

Why should lead, zinc, or galvanized marks not be made on exhaust systems?

Back 241

They will cause cracks when heated because of a change in molecular structure.

Front 242

What is the indication of exhaust gas leaks?

Back 242

Flat gray or sooty black deposits

Front 243

How are exhaust system internal baffles or diffusers inspected?

Back 243

Disassembled for visual inspection

Front 244

Why does a failure of exhaust system internal baffles or diffusers sometimes cause a loss of engine power?

Back 244

Restricts the flow of exhaust gases.

Front 245

What happens to engine power when a heat exchanger leaks exhaust gases into the engine induction system?

Back 245

There is a loss of power.

Front 246

Where are exhaust manifold and stack failures usually found?

Back 246

At welded or clamped points.

Front 247

What is a common cause of turbocharger waste gate sticking?

Back 247

Coke deposits or carbon build up.

Front 248

Why are turbocharged exhaust system leaks very damaging at high altitudes?

Back 248

Due to the pressure differential the leak will escape with torch-like intensity.

Front 249

What are exhaust system coke deposits.

Back 249

Excessive carbon build up.

Front 250

What would happen to turbine engine performance if the exhaust nozzle shape is changed?

Back 250

Performance and exhaust gas temp would change.

Front 251

What are the components of a typical turbine exhaust nozzle?

Back 251

1. Tail cone

2. exhaust duct

3. Support struts

Front 252

What is the purpose of thrust reversers?

Back 252

Aid in decelerating an aircraft after landing.

Front 253

What is the function of the thermocouple probes in a turbine exhaust tailpipe?

Back 253

Measure exhaust gas temp

Front 254

How do you determine the repairability of a damaged propeller blade?

Back 254

Reference the manufacturer's maintenance manual

Front 255

What is the purpose of propellers?

Back 255

The blades produce forces that create thrust to pull or push the airplane through the air.

Front 256

What is a fixed pitch propeller?

Back 256

The blade angle is built in to the propeller and cannot be changed.

Front 257

What type of blade angle change will occur on a propeller, that is pitch controlled by a propeller governor, during constant power dive?

Back 257

The blade angle increases to overcome overspeeding.

Front 258

Other than maintaining constant speed, what are two actions of some controllable propeller systems?

Back 258

Reverse and feathering

Front 259

What is the purpose of metal tipping fastened to a wooden propeller leading edge and tip?

Back 259

Protect the propeller from damage.

Front 260

When engine vibration is reported, what should be checked to determine if it is caused by the engine or propeller?

Back 260

Blade tracking and low blade angle setting.

Front 261

What is blade tracking.

Back 261

Determining the positions of the tips in relation to each other.

Front 262

What may be used to determine propeller blade angle?

Back 262

Propeller protractor

Front 263

What should be used to clean aluminum propeller blades and hubs?

Back 263

Iaw the manufacturer's manual.

Front 264

What positions of a two bladed propeller are used during a static balance check?

Back 264

Vertical and horizontal

Front 265

What two forces are balanced in a propeller governor in an on-speed condition?

Back 265

Spring and flyweight.

Front 266

On light aircraft propellers, what is the purpose of centrifugal force acting on propeller blade counterweights?

Back 266

This action is to increase propeller blade pitch.

Front 267

What happens to a constant speed feathering propeller system when the propeller governor oil pressure drops to zero?

Back 267

Propeller will feather.

Front 268

What may be adjusted in a hydromatic propeller system to increase or decrease rpm?

Back 268

Propellor governor

Front 269

What type systems are used for propeller ice control?

Back 269

Fluid (alcohol) and electrical

Front 270

What type of nondestructive testing should be accomplished to the propeller after blending?

Back 270

Procedures recommended by the manufacturer.

Front 271

What is the function of the negative torque sensing device in a turbopropeller system?

Back 271

the device mechanically actuates a linkage in the prop control which results in increased blade angle until propeller is not driving the engine.

Front 272

How is feathering accomplished on a constant speed propeller?

Back 272

Releasing the governor oil pressure allows the counterweights and feathering spring to feather the propeller.

Front 273

What is the purpose of an oil accumulator connected to a propeller governor?

Back 273

Unfeathering oil pressure

Front 274

What unit is used to sense propeller rpm in the light twin aircraft propeller synchronizer?

Back 274

The prop governors have magnetic pickups that count the prop revolutions, and send a signal to the synchronizer unit.

Front 275

What places the greatest demand on auxiliary power units?

Back 275

Bleed air

Front 276

What starts a typical apu?

Back 276

With its own electrical starter and battery power.

Front 277

Where does an APU get its fuel?

Back 277

Main aircraft fuel tank

Front 278

What speed does an apu operate at and how is this speed maintained?

Back 278

At or near its rated speed regardless of electrical or pneumatic loads imposed. The APU fuel control automatically adjusts the fuel flow to maintain the rated speed.

Front 279

How does a heavily loaded apu prevent itself from over heating (exceeding max EGT)?

Back 279

A load control valve modulates the pneumatic load to maintain EGT's within limits.

Front 280

How is APU shut down and why is this procedure used?

Back 280

Completely unload the APU of all external demands by closing the bleed air valve, it is then ran for a specified amount of time. The cool down period is typically 3 minutes. If a heavily loaded APU is abruptly shutdown thermal shock could occur.

Front 281

What are the operational effects of following the required cool down cycles of the APU?

Back 281

It adds longevity to the life of the APU.

Front 282

How long is a typical cooling down cycle of an apu?

Back 282

3-4 min

Front 283

How is the operational speed of an apu controlled?

Back 283

APU fuel control adjusts the speed by adjusting fuel flow.

Front 284

Name at least 2 uses for an apu?

Back 284

1. Engine start

2. aircraft ground operation

3. Anti-icing

Front 285

What type of operational practices can cause thermal shock to an apu?

Back 285

Not following the cool down cycle.

Front 286

What powers the variable inlet guide vanes on an apu?

Back 286

Fuel pressure from the fuel control system.

Front 287

What does a typical apu consist of?

Back 287

1. Air inlet

2. Compressor

3. combustion

4. Turbine

5. fuel control

6. load control valve

Jeppesen answer- A small power turbine for power and bleed air, and an electrical generator.

Front 288

What is the function of a typical apu?

Back 288

1. air pressure for engine starting

2. anti-icing

3. electrical power for aircraft system operation both inflight and on ground.

Front 289

A cold cylinder is found when troubleshooting a running engine. What does this indicate?

Back 289

No combustion in that cylinder.

Front 290

When an engine is overhauled, how is its total time affected? When an engine is rebuilt, how is its operating history affected?

Back 290

Overhauled- total time must be continued and TSO entered into engine log.

Rebuilt- granted zero time status and considered to have no previous operating history.

Front 291

What inspections should be performed after a propeller strike without sudden stoppage?

Back 291

1. Inspect engine mounts, crankcase and nose section for damage.

2. Inspect oil and oil filters for metal particles.

3. Inspect crankshaft and driveshaft for cracks or misalignment.

Front 292

What does it mean if an engine part is within "serviceable limits"?

Back 292

It means the part is within the manufacturer's limits and can be used in an engine.

Front 293

What publication is used to check an engine for normal operation?

Back 293

Manufacturer's maintenance manual

Front 294

A weak cylinder is found during a compression check. What must be inspected?

Back 294

Pressure is transmitted equally in all directions.

Front 295

What purpose does an oil analysis serve?

Back 295

Metal particles show normal and abnormal wear of the engine. This helps in evaluating the engine's internal condition.

Front 296

What inspection should be performed on an engine that has been in storage?

Back 296

Corrosion inspection

Front 297

Is the aircraft electrical system required to power a cylinder head temperature gauge?

Back 297

No. A thermocouple is used as the electrical source.

Front 298

What are the possible indications of an oil pressure transmitter or indicator malfunction?

Back 298

A severe or sudden drop in oil pressure while the oil temperature remains normal and the oil supply remains full.

Front 299

What is shaft horsepower?

Back 299

An indication of the torque developed by a turboprop or turboshaft engine.

Front 300

What is fan blade shingling?

Back 300

Overlapping of the mid span shrouds of the fan blade.

Front 301

When a turbofan or turbojet engine is shut down, what should a mechanic listen for during coastdown?

Back 301

Any rubbing sound or unusual noises from the engine.

Front 302

Why are compressor washes performed and what methods are commonly used?

Back 302

To remove any contaminants from the compressor section and improve engine performance. The fluid wash and abrasive grit are most common.

Front 303

How are gas turbine engine tachometers calibrated?

Back 303

They are calibrated in percent r.p.m.

Front 304

On a turbine engine, what is the engine pressure ratio and what does it indicate?

Back 304

It is the ration between the total inlet pressure and total turbine exhaust pressure and is used to indicate the thrust developed by the engine.

Front 305

On a turbine engine, what does exhaust gas temperature (EGT) indicate and how is it obtained?

Back 305

EGT is the average temperature of the turbine discharge gasses and is obtained by thermocouples placed near the turbine exit.

Front 306

What could happen if the induction system becomes obstructed?

Back 306

The engine may not be able to produce it's rated power or may not run at all. This may also be an indication of a dirty air inlet filter.

Front 307

What causes fuel evaporation ice?

Back 307

Fuel evaporation ice is formed because of the decrease in air temperature resulting from evaporation of the fuel after it is introduced into the air stream.

Front 308

Is carburetor throttle ice more likely to occur at a higher or lower power setting? Why?

Back 308

At a lower power setting because the throttle is partly closed, offering a larger surface area for ice accumulation.

Front 309

What is used to power a turbocharger?

Back 309

Engine exhaust gas directed onto the turbocharger turbine.

Front 310

In a pressurized reciprocating aircraft, what component in the turbocharger system is used to limit the amount of turbocharger airflow used for cabin pressurization?

Back 310

The sonic Venturi

Front 311

What is the function of a divergent-shaped jet engine inlet during subsonic flight?

Back 311

It causes the air velocity to decrease with a subsequent increase in air pressure

Front 312

Where are bellmouth inlet ducts typically found?

Back 312

On helicopter engines

Front 313

How do Venturi-type particle separators, found on many turbine powered helicopters , function?

Back 313

A venturi is used to accelerate the flow of incoming air and debris through a curved intake. The debris gain too much inertia to allow it to follow the curved intake towards the engine, and is channeled away from the compressor.

Front 314

What are the most common methods used for anti-icing of turbine engine inlet ducts?

Back 314

Engine bleed air and electric heating elements.

Front 315

What is the purpose of the exhaust system?

Back 315

To remove high temperature noxious gases.

Front 316

What drawback in using collector-type exhaust systems is more than offset when used on turbocharged engines?

Back 316

The loss of horsepower due to exhaust system back pressure.

Front 317

What could result if the internal baffles or diffusers in an exhaust system fail?

Back 317

The flow of the exhaust gasses could be restricted, resulting in loss of engine power.

Front 318

What kind of material is normally used to make the muffler shrouds found in the exhaust system?

Back 318

Stainless steel

Front 319

How does a noise suppressor found on older turbojet engines work?

Back 319

It converts low frequency sound, which is audible over great distance, into high frequency sound, thus reducing the sound footprint.

Front 320

What are the two most commonly used types of thrust reversers?

Back 320

The clamshell or cascade

Front 321

How much thrust do the thrust reversers produce compared to the engine's full forward thrust?

Back 321

Substantially less

Front 322

What are the hazards of operating some thrust reversers at low ground speeds?

Back 322

Ingestion of foreign objects stirred up by exhaust gasses and re-ingestion of hot exhaust gasses.

Front 323

What is the purpose of an accelerating system?

Back 323

It provides an immediate but brief increase in fuel flow in the venturi to enrich the mixture.

Front 324

When the mixture is placed in the idle-cutoff position, a slight rise in rpm is noted prior to the engine decelerating. What does this indicate?

Back 324

The idle mixture is set correctly.

Front 325

What maintains the fuel pressure in a pressure-injection carburetor?

Back 325

An engine driven fuel pump.

Front 326

What happens if the manual mixture control of a pressure injection carburetor is moved to the idle cutoff position?

Back 326

The engine stops

Front 327

What are some of the advantages of fuel injection systems over carburetor systems?

Back 327

Less danger of induction icing, better acceleration, better fuel distribution, better fuel economy, reduced overheating of individual cylinders.

Front 328

What are the two major components of a supervisory electronics engine control?

Back 328

The ECU and the Hydromechanical fuel control

Front 329

What are some of the advantages of a full-authority digital engine control (FADEC) over a Hydromechanical fuel control?

Back 329

1. Better fuel economy

2. Improved starts

3. Requires no engine trimming

4. Provides engine limit protection

Front 330

What do turbine engine fuel spray nozzles do?

Back 330

Inject fuel into the combustion area.

Front 331

What are the different engine indications used for trimming a turbine engine?

Back 331

Either EPR or rpm is used depending on the particular engine.

Front 332

What maintenance adjustments are normally allowed on an installed Hydromechanical fuel control?

Back 332

Specific gravity for fuel, idle rpm, and max rpm.

Front 333

What is used to keep water, sediment, and foreign matter out of the carburetor?

Back 333

The main fuel strainer

Front 334

What is the purpose of a pressure relief valve in a constant displacement pump?

Back 334

It returns excess fuel not required by the engine to the inlet side of the pump.

Front 335

What is the purpose of a shear section of the driveshaft in a dual element constant displacement pump?

Back 335

If one element seizes, a portion of the driveshaft seizes, allowing the other element to continue to operate.

Front 336

What is the purpose of a bypass valve in an engine fuel system micron filter?

Back 336

It is a safety feature that allows fuel to flow to the engine if the filter becomes blocked.

Front 337

What is the purpose of a duplex fuel nozzle?

Back 337

A duplex fuel nozzle discharges two different spray patterns. The spray pattern is wider during start up and acceleration and narrows when engine speed increases above idle.

Front 338

How can the remaining service life of starter generator brushes be determined?

Back 338

By visually inspecting the amount of wear groove remaining on the brushes.

Front 339

What components of the starter-generator require periodic inspection?

Back 339

The commutator and brushes.

Front 340

Between field and armature windings in starter-generators, which ordinarily receive current for operation in the start mode?

Back 340

Generally, both field and armature receive current for operation in the start mode.

Front 341

What are the possible sources of low pressure compressed air used for starting jet transport aircraft equipped with air turbine starters?

Back 341

1. A ground power unit (GPU)

2. On-board auxiliary power unit (APU)

3. Compressed bleed air from an already running engine

Front 342

Why is magneto timing so important?

Back 342

For an engine to run properly, the spark plug in a cylinder has to fire at a specific time. To produce the required energy for the spark at the required time, the magneto must be in the e-gap position, the breaker points must start to open, and the distributor must be electrically aligned with the particular cylinder. Internal timing and magneto-to-engine timing must be adjusted during install.

Front 343

What reduces arcing in the points and also aids the collapsing of a magnetic field in a magneto?

Back 343

A capacitor

Front 344

What is the P-lead and how does it function?

Back 344

The P-lead connects the ignition switch to the primary circuit of the magneto. When the ignition switch is turned off, the P-leads on both magnetos are grounded. When the ignition switch is turned to the "left", the right magneto is grounded, so that only the left magneto operates, and vice versa.

Front 345

Why are turbine engine igniters generally not susceptible to carbon fouling?

Back 345

Because the high energy sparks they produce clean off any deposits on the firing end.

Front 346

What is the function of a duty cycle in relation to a turbine engine ignition system?

Back 346

A duty cycle allows the operation of the ignition system for a given amount of time, and is then followed by a minimum specified cooling down period.

Front 347

What are the three main components of turbine engine ignition system?

Back 347

1. Ignition exciters

2. High tension leads

3. Igniters

Front 348

When the engine is operating what does an ammeter/ load meter indicate when connected to: 1. Battery positive lead? 2. Generator output lead?

Back 348

When connected to the battery positive lead, the ammeter indicates whether the battery is charging or discharging. When connected to the generator output lead, it indicates the current produced by the generator, or electrical system load.

Front 349

What is done to ensure that each generator shares the load in a multiple generator system?

Back 349

The generators are paralleled.

Front 350

What is the most common type of alternator used in most aircraft AC systems?

Back 350

The three phase alternator

Front 351

What does the speed of rotation and number of poles of an alternator determine?

Back 351

The frequency of the alternator output.

Front 352

What are some of the methods used to maintain 400 Hertz alternator output frequency on large turbojet or turbofan engines?

Back 352

Constant speed drives, integrated drive generators, and variable speed constant frequency power systems (VSCF)

Front 353

Name the major parts of a DC motor?

Back 353

The armature, field, brushes and frame assembly.

Front 354

Name the components of a direct cranking electric starter system.

Back 354

An electric motor, reduction gears, and an automatic engaging and disengaging mechanism.

Front 355

Name three types of DC motors?

Back 355

Series, shunt, compound

Front 356

What type of DC motor is commonly used for a reciprocating engine starter and why?

Back 356

A series wound motor is commonly used because it has high starting torque under heavy load conditions.

Front 357

What are the operating modes of a turbine engine starter generator?

Back 357

It operates first as a starter, then as a generator once the engine is running.

Front 358

What is a possible indication when a starter drags?

Back 358

A dirty or worn starter commutator.

Front 359

Where would wire with high temperature insulation be used?

Back 359

When they run close to high temp areas such as exhaust stacks or heating ducts.

Front 360

What is the size standard for electrical wire used in US manufactured aircraft?

Back 360

The American Wire Gauge (AWG)

Front 361

How are wire sizes represented?

Back 361

By a numbered gauge size. The smaller wires are represented by larger numbers. The smallest size wire normally used in aircraft is 22-gauge

Front 362

What is the maximum slack allowed between the supports of a single wire or bundle installation?

Back 362

Not over 1/2 inch

Front 363

Name two important characteristics of engine oil.

Back 363

The oil must be light enough to circulate freely yet heavy enough to provide the proper oil film at engine operating temperatures.

Front 364

What could happen to an oil that is too low in viscosity at normal engine operating temperatures?

Back 364

It may become so thin that the oil film between moving parts is easily broken, resulting in premature wear.

Front 365

What is a possible indication of low oil pressure together with high oil temp?

Back 365

A low or inadequate oil supply.

Front 366

In ashless dispersant (AD) oils, what function does the dispersant perform?

Back 366

The dispersant causes sludge-forming materials to repel each other and remain in suspension until they can be trapped by the oil filter or drained. This keeps the oil passages free of harmful deposits, and the inside of the engine clean.

Front 367

Where is the oil temperature bulb usually located?

Back 367

At the engine oil inlet.

Front 368

What should be done if metal particles are found in an engine oil filter?

Back 368

Follow engine manufacturer's maintenance instructions.

Front 369

What is the purpose of cooling fins?

Back 369

They provide a larger cooling surface area for removing heat from cylinder heads. Airflow from around the cooling fins transfers the heat from the cylinder heads to the air.

Front 370

What should be done when cooling fin damage is discovered?

Back 370

Some cooling fins can be repaired depending on the damage iaw Manufacturer's m/m. The cylinder should be replaced if amount of damage to fin is excessive.

Front 371

How are turbine engines cooled?

Back 371

They are cooled by air passing through the engine. 75% is used for cooling and 25% is for combustion. The air cools the combustion chamber and turbine.

Front 372

What is the relationship between turbine engine upper temperature limits and power produced?

Back 372

The higher a combustion temperature that an engine can withstand without damage the more power it is capable of producing.

Front 373

What is the approximate percentage of air passing through a turbine engine that is used for cooling rather than combustion?

Back 373

75%

Front 374

What can be done to effectively allow higher gas temperatures in the turbine section of some engines?

Back 374

Compressor bleed air ducted through hollow sections in the turbine inlet guide vanes and first stage rotor blades can lower temperatures enough to prevent heat damage.

Front 375

What is the likely cause of a false fire warning?

Back 375

The engine fire sensing loop is bent or kinked excessively.

Front 376

What are fire extinguishing systems designed to do?

Back 376

They are designed to dilute the oxygen levels around the engine to a point that does not allow combustion, or to reduce temperatures below the ignition point.

Front 377

What elements must be present for a fire to occur?

Back 377

An ignition source such as heat or a spark, fuel and oxygen.

Front 378

What group of fire extinguishing agents are no longer manufactured because of environmental concerns?

Back 378

Halons (Freons or CFC's) were no longer manufactured after 1995. However existing stocks may still be used under strict guidelines.

Front 379

How is a fire extinguishing system with a high rate of discharge classified?

Back 379

As an HRD

Front 380

What is the difference between a fixed pitch propeller and a controllable pitch propeller?

Back 380

A fixed pitch has a built in blade angle that cannot be changed by the pilot, only by the manufacturer or approved repair station. A controllable pitch can be changed by the pilot and is usually controlled by a governor that maintains constant speed, some may provide reverse pitch and feathering.

Front 381

How are wooden propeller blades protected from wear and damage?

Back 381

By metal tipping fastened to the leading edge and tip.

Front 382

What are the functions of a constant speed propellor governor?

Back 382

It boosts engine oil pressure before it enters the propeller hub, it senses rotational speed of the propeller, and then adjusts the oil flow to the propeller hub to change pitch and, therefore, speed of the propeller.

Front 383

What is the purpose of propeller counterweights?

Back 383

Centrifugal force acting on the counterweights causes the blade angle to increase.

Front 384

What is meant when a propeller governor is in an "on-speed" condition?

Back 384

The governor is not accelerating or decelerating and the speeder spring and flyweight forces are in balance.

Front 385

What is an unfeathering accumulator?

Back 385

It is an oil accumulator used to provide pressure to unfeather a propeller.

Front 386

What is alpha range and beta range and where are they found?

Back 386

Pertain to operating modes of turboprop reversible pitch propellers. Alpha range- the propeller is operating in the standard, constant speed mode, which is usually in flight. Beta range- the propeller is operating in the zero or minimum thrust range and negative thrust or reverse thrust mode, which is usually on the ground.

Front 387

What propeller repairs can be performed by a certified mechanic with a power plant rating?

Back 387

Only minor repairs and alterations can be performed by a power plant mechanic. Major repairs by the manufacturer or certified repair station.

Front 388

How are wooden propellers generally cleaned?

Back 388

With a brush or cloth and warm water with mild soap.

Front 389

What are the two criteria used by many manufacturers to determine the amount of bend damage that can be repaired by cold bending of aluminum propellers?

Back 389

The extent of the bend and its blade section location.

Front 390

How can repair file marks be removed from an aluminum propeller?

Back 390

With very fine sandpaper.

Front 391

What is a propellor protractor used for?

Back 391

To measure propeller blade angle.

Front 392

What blade conditions can cause engine vibration?

Back 392

Vibration can be caused by a propeller being out of track and/ or balance, as well as incorrect blade angle setting.

Front 393

What controls both manifold pressure and rpm on an engine equipped with a fixed pitch propeller?

Back 393

The throttle

Front 394

What FAA approvals are required when installing an engine that is not on the aircraft type certificate?

Back 394

An STC or an FAA field approval.