Questions Flashcards
1
Q
What is the definition of a short circuit?
A
Unintentional low resistance path between component and ground
2
Q
What does a basic DC circuit consist of?
A
A battery source, resistance/load and conductors/wires.
3
Q
What is inductance?
A
Voltage is induced by magnetic flux lines in a coil of an AC circuit; opposite direction of applied voltage
4
Q
What is impedance?
A
Total opposition to the flow of current (total resistance)
5
Q
What is the total resistance of a circuit known as?
A
Impedance
6
Q
What causes opposition to the flow of current in an AC circuit?
A
Inductive and capacitance reactance
7
Q
What is the unit of impedance?
A
Ohms (total resistance)
8
Q
What 4 factors affect resistance of a conductor?
A
- wire gauge
- wire length
- temperature
- material
9
Q
How many watts equal one unite of horsepower?
A
746 watts
10
Q
What are the 3 types of circuits?
A
- series
- parallel
- complex (series and parallel)
11
Q
What should the specific gravity of an electrolyte of a fully charged lead acid battery be?
A
Between 1.275 and 1.300
12
Q
What temperatures would adjustments have to be made for a state of charge check when using a hydrometer on a lead-acid battery?
A
Below 70°F or above 90°F
13
Q
How are battery compartments protected against corrosion?
A
- corrosion resistant paint
(bituminous paint)
14
Q
What should be 3/8ths of an inch above the plates of a battery if properly serviced?
A
The electrolyte level (or if battery has baffle plates between cells; up to the hole/)
15
Q
What happens with a cell imbalance in a nickel-cadmium battery?
A
The cell has low internal resistance; the current increases, causing it to heat up.
16
Q
The basic unit of measure for inductance
A
Henry
17
Q
What is ‘tare weight’?
A
The weight of extra equipment like jacking pads, chocks, blocks and chains. They need to be subtracted to obtain the empty weight.
18
Q
What numbers are used for close tolerance bolts?
A
AN-173 to AN-186 (Hex head)
NAS-80 to NAS-86 (Countersunk)
19
Q
What does the triangle mean on a hex head bolt?
A
Close tolerance - machined to more precise dimensions and made for high performance applications
20
Q
What is a rivnut?
A
Threaded body, expanded into the aircraft structure
21
Q
What is the depth of penetration of a fillet weld?
A
25-50%
22
Q
What common materials are cotter pins made out of?
A
Low carbon steel and stainless steel
23
Q
What should be the width of a weld bead and depth of penetration when making a butt weld?
A
3-5 times the thickness of base metal and 100% penetration
24
Q
What is bolt diameter and lengths measured in?
A
Diameter - 1/16th inch
Length - 1/8 inch
25
What is the purpose of close tolerance bolts?
Used in high performance applications where subject to severe vibrations and load reversals. Machined to higher standards and must be driven in with a hammer
26
Steps of heat treatment…
- Heated to predetermined temp
- heat soaked
- quenched
27
Why is alloy steel that is responsive to heat treatment usually less suitable for wealding?
Due to its tendency to become brittle and lose its ductility around the weld
28
What are two methods of case hardening?
- Nitriding
- carburising
29
What are characteristics of a cold weld?
- appears rough
- irregular
- edges are unfeathered
- cold laps caused by insufficient heat & improper penetration
30
What are some non-destructive testing methods?
- dye penetrant
- eddy current
- X-ray
- coin tap
- visual inspection
31
What NDT inspection methods can be performed without removing surface coatings?
Eddy current inspection
32
Most common type of corrosion?
Surface corrosion
33
Types of washers…
- spring
- flat
- lock tooth
- tab
- finishing
34
Where can you find the torque of a bolt if not listed in maintenance procedures?
The standard torque table
35
What steel alloy is noted for toughness?
Chrome-Molybdenum Steel
36
What is a portable hardness tester is commonly used for testing?
Barco tester
37
Where are thermoplastics & thermosetting used?
- thermoplastic (windshields)
- thermosetting (used as matrix material in composites)
38
Name some reinforcing materials in structural composite laminates?
- kevlar
- fibreglass
- graphite
39
What substances are commonly used as the matrix material in composites?
- polyester resin
- epoxy resin
40
What is another name for aramid material?
Kevlar
41
What is used to repair threads?
Helicoil
42
Why must aircraft and fuel trucks be grounded together with a grounding cable?
Prevents static electricity that could result in explosion
43
What are the functions of tetraethyl lead in avgas?
- lubricate
- reduce detonation
44
Which publication lists the standard FAA hand signals a taxi signalman should use?
FAA airman’s information manual (AIM)
45
What types of fire can a CO2 fire extinguisher be used on?
A, B and C
46
Why are fingers not curled over prop blades when hand propping an engine?
Kickback could break them and draw your body into the blade path
47
What are the 5 common forms of corrosion?
F-DISS
Fretting, dissimilar metals (galvanic), Intergranular, Surface and Stress
48
What factors affect corrosion?
- Temperature
- types of metal
- conditions of protective coatings
- electrolytes in dissimilar metals
49
What is filiform corrosion?
Surfaces that have not had the correct chemical treatment prior to painting
50
What are the basic steps when removing corrosion?
- clean and strip area
- remove corrosion
- neutralise
- restore protective finish
51
What can be used to repair anodised surface of an aluminium part?
Alodine or other chemical conversion coating
52
What form of corrosion can be found in battery compartments?
Chemical corrosion
53
What is wet wash and dry wash cleaning?
**Wet Wash**
Used to remove oil/grease etc
**Dry Wash**
Used to remove dust films and small accumulations of dirt
54
Define the aspect ratio of a wing
The ratio of length (span) to its width (chord)
55
Define pi
The ratio of the circumference to the diameter of any circle
56
Define the root of a number
The base number that is multiplied by itself
57
What is a quadrant?
A quarter of a circle
58
What is a closed shape made up of 3 or more sides?
A polygon
59
What is a parallelogram?
Two pairs of parallel sides (rhombus)
60
What is the name of the atmospheric condition where cool air is trapped near the earth by warm air?
Temperature inversion
61
What is the speed of sound through air at standard sea level?
761mph
62
What is specific gravity?
The ratio of a substance’s density to the density of pure water
63
What are the 4 forces acting on an aircraft in flight?
Thrust, lift, drag and gravity
64
What is autorotation?
When helicopter blades spin without engine power as air flows through the rotor 
65
What is Blade flapping?
Increased angle of attack on retreating blade and decreasing angle attack on advancing blade 
66
What is the name of the imaginary line that runs from the leading edge to the trailing edge of an airfoil? 
The chord line 
67
What are the four ways of measuring temperature? 
Fahrenheit, Celsius, kelvin, Rankin 
68
What is relative humidity? 
The ratio of the amount of water vapour actually present in atmosphere, as compared to when the air is saturated with water vapour 
69
What type of materials are used in metallic honeycomb construction?
Stainless steel, titanium, magnesium, plywood, resin, impregnated, paper, E-glass and nylon in various combinations 
70
What calculations must be made when bending sheet metal? 
Set back and bend allowance 
71
What factors are used to determine setback? 
The radius plus the thickness 
72
When bending sheet metal, how should the grain be in relation to the bend? 
Perpendicular to the bend 
73
What is the bend tangent line? 
The line at which the metal starts to bend (imaginary line)
74
What is a Joggle?
And offset near the edge of a piece of sheet metal allowing clearance for another sheet, or extrusion 
75
What are several methods used in forming sheet metal? 
Folding, bumping, crimping, shrinking, and stretching 
76
What kind of metal forming is done by bumping?
Compound curves 
77
What is anodising?
An electrolytic bath, causing a thin film with hydroxide to form on the surface. It provides excellent resistance to corrosion and excellent bond for painting 
78
What are the proper dimensions for the shop head of a rivet?
1.5 x diameter in width & 1/2 diameter in height
79
What is a bonded honeycomb construction? 
A laminar construction consisting of alternating dissimilar metals.
Reduces weight
80
What procedures should be used to prevent damage to the hole when drilling through plexiglass? 
- backed with Wood
- slow fed
- Drillbit modified to 60° tip angle 
- cutting edge to zero-rake angle
- back lip clearance angle 12-15°
81
What is crazing? 
Hairline cracks in the surface of a plastic due to heat damage causing excessive stress 
82
What is used for Hole filling in a bonded honeycomb repair?
Potting compound 
83
What is a warp line? 
A highlighted strand in the fabric used for ply orientation 
84
What is a barcol tester? 
Portable device that spikes into composite. The depth of penetration is measured to determine if resins have cured. 
85
What is a helicopter cyclic?
It is used to control the main rotor and change the helicopters direction of movement 
86
What needs to be done to prepare an aircraft for an annual or 100 our inspection?
- Open all inspection plates and access doors
- Thoroughly clean the aircraft and engine 
87
What are the operating conditions which make the 100 our inspection mandatory?
Required only for aircraft carry persons for hire always used to give flight instruction for hire 
88
Does an aircraft been operated under a progressive inspection program require a 100 hour inspection if it is used to give site instruction for higher? 
No
89
What are the three auxiliary, landing gear types?
- nose gear
- tail gear
- outrigger type
90
What is the purpose of the rubber O-ring mounted on the main surface of the outer wheel half of a split-type wheel?
Preventing air leakage from the tubeless tire 
91
What are the three types of aircraft brake systems? 
- independent
- Power boosted
- Power control 
92
What is the purpose of the shuttle valve in a power control system? 
It’s isolates the emergency brake system from the normal brake system 
93
What safety procedure should be followed when inflating tires?
Inflate them inside of a cage, where ever possible 
94
What are two methods for bleeding brakes? 
Gravity and pressure methods 
95
When installing a chevron seal, what must be considered?
It is directional and must be installed with pressure going towards the open side of the seal 
96
What are the filters used in aircraft pneumatic systems?
- Paper type
- screen type 
97
What are two types of accumulator housings?
Spherical and cylindrical 
98
Name, three types of hydraulic accumulators 
- diaphragm
- bladder
- piston 
99
What protects direct pressure type hydraulic pressure gauge from pressure surges?
A dampening device in the form of a very small restrictor 
100
The production of gas is oxygen for commercial aircraft cylinders is through what process? 
Liquefying air
(Sodium chlorate)
101
What are the two groups of independent cabin compressors?
Positive displacement and centrifugal compressors
102
What are three methods of supplying heat to the conditioned air, when the heat of compression is not sufficient?
- Fuel burning Combustion heaters
- electric heaters
- exhaust gas air-to-air heat exchangers
103
What are the sources for ventilation air in a combustion heater?
Blower is used on the ground
In-flight, Ram air
Cabin compressors 
104
What are the components in a vapour cycle cooling system? 
Compressor
Condenser
Receiver dryer
Expansion valve
Evaporator 
105
How is a vapour cycle cooling system compressor lubricated?
Specialised refrigerant oil 
106
How are high and low pressure, oxygen cylinders identified?
High pressure - green in colour and have the words “aviators breathing oxygen” in White, 1 inch letters.
Low pressure are painted light yellow 
107
What are three ways supplemental oxygen can be carried in an aircraft?
Liquid
High pressure
Chemical candle 
108
What is a roots blower?
A type of engine driven compressor
109
What are the sources of power to a gyroscopic instrument?
Vacuum
Electricity
Air pressure 
110
What is a syncro-type remote indicating system?
Show movement and position of landing gear wing, flaps, cooler, doors, or other movable parts of an aircraft.
It’s an electrical system, transmitting information from one point to another. Three most common types are Autosyn, Magnesyn and Selsyn.
111
What is meant by swinging a Compass? 
The adjustment of the north, south east, and west magnets to reduce deviation 
112
What is a tachometer used for in a crankshaft of a reciprocating engine, or the speed of the main shaft of a turbine engine? 
Indicates the speed 
113
What is a BNC type connector in a communication system?
Connector used with coaxial cables that takes 1/4 turn to fully seat
114
What are the typical components of a VOR system? 
Receiver, visual indicator, dipole, antenna, and power supply 
115
What are the basic components of an autopilot system? 
Gyros, servos and amplifier 
116
What are three types of servos used in autopilot systems? 
Hydraulic
Pneumatic
Electron
117
What is the frequency of an ELT? 
121.5 / 243 / 406 MHz
118
What is the minimum bend of a coaxial cable? 
10 times the size of the diameter 
119
At what intervals should coaxial cable be secured?
Approximately 2 feet / 24 inches
120
What are marker beacons? 
A part of the ILS system, indicating aircraft position on approach to the runway 
121
What is the indication of a middle marker beacon? 
Amber light and audible tone 
122
What is an ADF?
Automatic direction finder 
123
How often does the ATC transponder require certification?
Every 24 calendar months 
124
How is the weight of a bladder type fuel cell supported?
Depends on structure of cavity; supporting weight of fuel and maintains shape of the cell. Made of rubber or nylon impregnated with neoprene
125
What colour indicator is 10 gauge wire?
Yellow
126
Why do you feel selectors have detents?
To lock the switch into the selected position

127
What are four general types of fuel quantity gauges?
- sight glass
- mechanical
- electrical (transmitter/receiver)
- electronic (totalizer)
128
What is the purpose of a circuit breaker?
To protect the circuits and wires from fire
129
What are the two principles on which circuit breakers operate?
Thermal and magnetic
130
What are the factors to be considered when selecting wire size for electrical power?
Allowable power loss in the line
Permissible voltage drop
Current carrying ability 
131
What type of breakers are not acceptable for use in aircraft?
Auto reset breakers
132
What are the three most common faults that occur in electrical circuits?
Open circuits
Short-circuits
Low power
133
What size electrical conduit should be used for a specific cable bundle?
The inside diameter is 25% larger than the conductor bundle 
134
What would cause an AC motor to run too fast?
- excess supply of voltage
- motor field windings shorted
135
How is the output voltage of an alternator controlled?
Voltage regulator to control the exciter field current
136
What are two items that wear on a starter generator?
- commutator
- brushes
137
What are two types of AC generators?
- single phase
- 3 phase
138
What are two methods of inflating de-icer boots?
Engine bleed air
Engine driven air pump
139
What is the purpose of an air-oil separator in a pneumatic de-icing system?
- removes oil from the air to prevent deterioration of the rubber de-icing boots
140
What must be done before you can make a cold patch repair to a de-icer boot?
Clean, rough the surface of the boot & patch, glue and attach
141
What component of a pneumatic de-icer system system normally allows suction to be supplied to the boots to hold them down in flight?
The solenoid distributor valve
142
How is overheating prevented in a thermal anti-icing system?
A thermal switch (temp of 185°F will close and stop flow)
143
What problems are associated with electrically heated windshields?
Delaminating
Arcing
Scratches
Discolouration
144
What does arcing usually indicate in an electrically heated windshield?
A breakdown in the conductive coating
145
What type of power is used to operate a windshield wiper system?
Electrical or hydraulic power
146
What are the two most common fire extinguishers?
Halon 1211
Water
147
What colour does a CO detector change to when carbon monoxide fumes are present?
Silica gel - changes to Green
148
What type of extinguishing agent is usually found in HRD system?
Halogenated hydrocarbons
149
What type of fire extinguisher is recommended for brake fires?
A dry powder extinguisher
150
What type of fire extinguishers are used for interior aircraft fires?
Water, CO2 and dry chemical
151
At what time interval is the next hydrostatic test due on a portable fire extinguisher?
5 years from the last test date
152
What is the operating flexibility of an engine?
The ability of an engine to run smoothly at all speeds
153
How are reciprocating engines classified?
In line, radial and opposed
Or by cooling method (liquid or air cooled)
154
What are the different types of piston rings?
- scraper
- compression
- oil control
155
What is the purpose of the oil control rings?
They provide the oil film on the cylinder walls and control thickness
156
What type of piston rods are in radial engines?
Master and articulating rod assembly
157
What types of bearings are used in reciprocating engines?
Plain
Roller
Ball
158
How do you detect valve blow by?
Hissing or whistling sound when pulling the prop by hand (compression check should be completed)
159
What is the main purpose of valve overlap?
Volumetric efficiency (lowers temp of cylinders)
160
What inspections would you do to the valves on complete engine overhaul?
Compression strength check
Visual inspection for cracks/corrosion
Cleaned thoroughly
161
What is the purpose of sodium filled stemmed valves?
Excellent hear conductor; the sodium melts and allows heat transfer from valve head to the stem
162
What are crankshaft dynamic dampers?
Floating dampers in the counterweight assembly reduce crankshaft vibrations
163
How would you do a runout check?
Remove the propeller; attach dial indicator and rotate crankshaft to check for misalignment
164
What cylinder is engine to magneto timing based on?
Cylinder number 1 (around 30 degrees before TDC of compression stroke)
165
What instrument(s) can be used to check bore for out of roundness?
Dial indicator
Telescopic gauge
Outside/inside micrometer
166
Where is a crack most likely to occur on a piston?
Where the piston pin connects
167
What should be done to repair a loose stud in an engine crankcase?
Remove the stud; inspect the hole for size and condition of threads. Replace
168
What is an indication that primer is leaking or is open during engine operation?
The engine will not idle properly
169
What is the term **thermal efficiency**?
The ratio of net work produced by the engine to the chemical energy supplied
170
What is the major difference between a turbo prop and a turbo fan engine?
The turbo prop normally has more turbine stages
171
What is an indication of a turbojet engine is out of trim?
High EGT and EPR at takeoff
172
What is a free turbine?
Drives a propeller or helicopter transmission
173
What are 3 types of ultrasonic inspection methods?
- resonance
- pulse-echo
- through transmission
174
What additional inspection should be carried out if cylinder compression is weak?
An internal inspection for improper tolerances
175
What type of FAA approval is required when a change to an engine design is not enough to require a new type certificate?
Supplemental type certificate
176
How does an oil analysis program help evaluate the internal condition of an engine?
A system that establishes a trend to measure engine health
177
What is the purpose of a hot section inspection of a turbine engine?
To determine the integrity of hot section components
178
What are the two units in an engine fuel control system?
A transmitter and an indicator
179
Where is a fuel flow transmitter located?
In the fuel line between the engine pump and the carburettor
180
What type of readout is indicated on a fuel flow system?
Calibrated to show fuel flow in lbs/hr
181
What exactly does a mass fuel flow transmitter measure?
The density mass of fuel that flows through it
182
What is the reason for monitoring fuel flow?
To make sure the engine is operating at the correct fuel-air mixture at a given power setting
183
Where is a carburettor air temperature bulb located?
In the intake passage to the engine
184
How can EGT of a turbine engine be checked without operating the engine?
By checking resistance to the thermocouples and circuits
185
What is the typical resistance of a cylinder head thermocouple cable?
2-8 ohms
186
What is the possible cause when a turboprop engine’s oil pressure drops off severely, and the oil supply remains? 
Oil pressure transmitter or indication malfunction
187
What are the three main categories of engine fire protection systems?
Spot detection
Continuous loop
Flame detectors
188
What are the two types of spot detection systems?
Thermoswitch and thermocouple
189
How many thermocouples are required for engine fire detection?
Depends on the size of the fire zone/circuit resistance
190
How does a thermal switch fire detection work?
When the heat sensitive switch closes, it closes the circuit to a light for information
191
What is the most common cause of a false fire warning in a continuous loop fire detection system?
Dents/kinks/crushed sensing element
192
What two methods are used to discharge fire extinguishing agents?
Mechanical and electrical
193
What is the colour marking used to identify fire extinguishing lines?
Brown with black diamonds
194
What is the purpose of the yellow and red disks in a turbine engine fire extinguishing system?
Yellow = pilot initiated
Red = thermal activated discharge
195
What are the basic components of a basic magnetic circuit?
Permanent magnet
Soft iron core
Pole shoes
196
How are new brushes installed in a generator?
Face of brushes are shaped to provide max contact with commutator using fine grade sandpaper and turning the commutator in direction of rotation until properly contoured. Blow out residue with compressed air
197
When should brushes be replaced in a generator?
When they are 1/2 of their original length
198
What units make up a DC generator?
Voltage regulator
Current limiter
Reverse current cutout
199
What are the 3 types of DC motors?
Series
Shunt
Compound
200
What are the parts of a DC motor?
Armature
Brushes
Commutator
Field frame
201
What do a the AWG system?
American wire gauge.
Smaller number = larger wire
202
How do you control the voltage output of a DC aircraft generator?
Controlling the strength of the magnetic field
- using a vibrating type voltage regulator
- three unit regulator
- carbon pile
203
What causes excessive arcing on generator brushes?
Dirty, rough or out-of round commutator
Worn brushes
Brush spring tension being low
204
How much slack is normally allowed between supports when installing single wires/bundles?
Not exceeding 1/2 an inch
205
What components make up a direct cranking electric starter?
Electric motor
Reduction gears
Automatic engage/disengage mechanism
206
Why is a series wound motor used for engine starting?
High starting torque under heavy load conditions
207
What is the most important property that an aircraft reciprocating engine oil must possess?
Viscosity
208
What is S.O.A.P analysis?
Spectrometric Oil Analysis Program
- establishes trend and engine wear
209
Where are carbon seals used in turbine engines?
Gearboxes
Starters
Main shaft seals
210
What is the purpose of the condenser in a magneto?
Prevents arching at the points
Hastens collapse of magnetic field around primary coil
211
What happens as the breaker points open in a magneto?
The primary coil magnetic field collapses; the flux lines cut across the secondary coil and induce a high voltage current which is sent to the spark plugs
212
What three conditions are required to fireplugs in a cylinder when the piston is in the prescribed position? 
E-gap position
Breaker points open
Distributor rotor aligned
213
What are two types of igniter plugs?
Annular gap
Constrained gap
214
What is a sign that a starter commutator is worn?
A noisy starter
215
What is the function of a metering jet?
It limits fuel flow when throttle valve is **wide** open
216
What could be the result of using excessively rich idle mixtures? 
Carbon fouling of the spark plug 
217
What is the purpose of the economiser system in a float carburettor? 
Closed at throttle settings below 60% to 70%
Provides additional fuel for engine, cooling to prevent detonation at higher throttle settings 
218
What operates an automatic mixture control on a pressure carburettor? 
The AMC contains sealed bellows that expand or contract with changes in atmospheric pressure in which the movement operates a tapered needle 
219
What are the three types of carburettor icing? 
Throttle, impact and fuel evaporation
220
What is the typical fuel pressure in a float type carburettor?
3-5psi
221
What two items are adjusted when setting idling conditions on a float carburettor?
Throttle stop
Idle mixture
222
What is the purpose of using boost pumps in a fuel system? 
Supply fuel during engine starting
Back up if engine pump fails
Keeps the pressure from becoming low enough to permit fuel to boil at high altitudes (Vapour lock) 
223
What are three general causes of vapour lock? 
Low fuel pressure
High fuel temperature
Excessive fuel turbulence 
224
What are the three major parts of a reciprocating engine induction system? 
Air scoop
Fuel delivery system
Intake manifold 
225
What are two general classifications of superchargers in reciprocating engine induction systems?
Externally driven (exhaust gases)
Internally driven (gear train)
226
What is the purpose of a distribution impeller in a radial engine? 
To break up fuel globules into finer particles for better distribution 
227
What are two general types of exhaust systems in use of reciprocating aircraft engines? 
Short Stack (open)
The collector system 
228
What exhaust system is generally used on low powered non-supercharged engines?
The short stack system 
229
What drawback in using collector type exhaust systems is more than offset one used on turbocharged engines?
Loss of horsepower due to exhaust system back pressure 
230
What are two types of propeller configurations? 
Tractor type
Pusher type 
