Airframe Flashcards
(212 cards)
1
Q
What forms of wood, other than solid wood, are used in aircraft?
A
Laminated and plywood
2
Q
What is a laminated wood assembly?
A
Two or more layers glued together with the grain of all layers approximately parallel
3
Q
How is aircraft plywood constructed?
A
It is usually made of an odd number of thin plies, or veneers, with the grain of each layer placed 90° with the adjacent ply or plies
4
Q
What wood species is used as a standard for strength properties?
A
Sitka Spruce
5
Q
How would you inspect wood for rot?
A
Inspect for a dark discoloration of the wood surface or gray stains along the grain
6
Q
What types of glues are used in aircraft wood structure repair?
A
Casein glue, plastic resin glue, resorcinol glue, and epoxy adhesives
7
Q
How does room temperature affect gluing wood structures using resin glue?
A
Curing time as well as joint strength
8
Q
When are mineral streaks acceptable?
A
If the inspection fails to reveal any decay
9
Q
Are hard knots acceptable in aircraft wood?
A
Yes, within specified limitations
10
Q
Why is compression wood not acceptable in aircraft construction?
A
It is very detrimental to strength
11
Q
Why is it necessary to scrutinize all stains and discoloration on wood?
A
To determine whether or not they are harmless, preliminary, or advanced decay
12
Q
Why are light steel bushings sometimes used in wooden structures?
A
This is to prevent crushing the wood when the bolts are tightened
13
Q
What are the results of insufficient gluing pressure?
A
Thick glue lines and a weak joint.
14
Q
What methods are used to apply pressure to wood glue joints?
A
Clamps, elastic straps, weight, vacuum bags, brads, nails, screws, or the use of electric and hydraulic power presses.
15
Q
What type of joint is generally used in splicing structural members?
A
A scarf joint.
16
Q
Why does the strength of a beveled scarf joint depend on the accuracy of the beveled cut?
A
The effective glue area will be reduced if the two beveled cuts are not the same.
17
Q
Always splice and reinforce plywood webs with what type of wood?
A
The same type of plywood as the original.
18
Q
What method will prevent a patch and a plywood pressure plate from adhering together due to extruding glue from the patch?
A
The use of waxed paper between the patch and the pressure plate.
19
Q
What areas of a wooden spar may not be spliced?
A
Under a wing attachment, landing gear, engine mount, and lift strut fittings.
20
Q
What is the maximum number of splices that should be made to any ‘one’ spar?
A
Two.
21
Q
What is the minimum temperature for curing wood joints with resin glue?
A
70°F.
22
Q
What two types of fabric are used for covering aircraft?
A
Organic and polyester (synthetic).
23
Q
What are the organic fibers used for covering aircraft?
A
Cotton and linen.
24
Q
What determines the quality and strength requirements for fabric-covered aircraft?
A
The original manufacturer by the never-exceed speed and wing loading.
25
What is the fabric warp?
The direction along the length of the fabric.
26
What is the purpose of reinforcing tape?
Most commonly used on rib caps after the fabric covering is installed to protect and strengthen the area for attaching the fabric to the ribs.
27
What should be done to a structure that will be covered with doped fabric?
Dope-proof it with a protective coating of an approved primer, varnish if it is a wood structure, and cover sharp edges, metal seams, the heads of rivets, and any other feature that might cut or wear through with anti-chafe tape.
28
What is one advantage of the envelope method of covering wings?
Edge distance.
29
How are the ventilation and drainage hole edges reinforced?
With plastic or aluminum grommets.
30
What methods are used to check the condition of doped fabric?
A test strip, punch tester, or, when results are marginal, a laboratory test is needed.
31
What is the maximum permissible deterioration for used aircraft fabric?
30% of the original fabric strength.
32
What is fabric selvage edge?
An edge of cloth woven to prevent raveling.
33
What rib lace spacing is used when the original spacing is unknown?
Use the chart in AC 43.13-1B.
34
What is a tie-off knot?
A modified seine knot is normally used on all stitches other than the starting stitch.
35
What are the common types of paint used on aircraft?
Primers, enamels, lacquers, and multipart finishing formulas (epoxies).
36
What is used with zinc chromate primer if it is too thick and needs to be thinned?
Toluene.
37
What are the two types of dope used for aircraft finishes?
Nitrate and Butyrate.
38
What is the purpose of zinc chromate primer?
It serves as a corrosion-resistant covering and base coat for protective topcoats.
39
What health and safety precautions should the mechanic observe when using solvents and thinners?
Some form of respirator or mask must be worn when spraying.
40
What are the three methods of applying paint?
Dipping, brushing, and spraying.
41
What paint system is compatible with epoxy topcoats?
Any paint system that is in good condition.
42
What is the cause of spray dust?
Incorrect spray gun setting of air pressure, paint flow, or spray pattern. The spray gun is being held too far from the surface, material is being improperly thinned, or the wrong reducers are being used with the finish coats.
43
What may cause spray paint to sag and/or run?
Applying too much paint to an area, or too much reducer in the paint (too thin, or incorrect spray gun setting of air-paint mixture).
44
What causes orange peel spray mottle?
Not enough reducer (too thick), the wrong type of reducer for the ambient temperature, material not uniformly mixed, the forced drying method is too quick, too little flash time between coats, or the ambient temperature is too hot or too cold.
45
What is a blushing paint finish?
A dull milky haze that appears in a paint finish.
46
What will cause a blushing paint finish?
It occurs when moisture is trapped in the paint, usually due to moisture in the air supply, adverse humidity, or temperature changes.
47
What could be the result of applying a coat of dope when the temperature of the dope room is too high?
Pinholes in the dope film.
48
What areas must be protected from damage when using paint remover/stripper?
All window material, vents, static ports, rubber seals and tires, and composite components that may be affected by the chemicals.
49
How can a mechanic determine if the control surfaces need to be checked for balance after painting?
Refer to the manufacturer's service manual and/or contact the manufacturer.
50
What happens to the rivet head stem when a self-plugging (friction lock) rivet is installed?
It is drawn up into the rivet shank, forming a plug in the hollow center of the rivet, and continues until the excess portion of the stem breaks off at a groove.
51
Give an example of a self-plugging mechanical lock rivet.
CherryLOCK
52
Describe the correct dimensions of a properly formed rivet head.
1½ diameter wide, ½ diameter tall.
53
What is bonded honeycomb construction?
Two relatively thin, parallel face sheets are bonded to and separated by a relatively thick, lightweight core.
54
Name two core materials used in special applications of bonded honeycomb construction.
Thermoplastics and carbon.
55
Name two causes of delamination or debonding of a honeycomb construction.
High or low-energy impacts and liquid ingression.
56
What is a potting compound repair used for in bonded honeycomb?
Hole filling.
57
What is done with the damaged area in bonded honeycomb?
The damaged area must be removed.
58
What will cause crazing in transparent plastic panels/windshields?
Stress. Improper handling and harmful cleaning solvents.
59
What should be done to twist drills that are to be used for drilling completely through Plexiglas?
The drill must be free from nicks and burrs that would affect the surface finish. Grind the drill with an included angle of 150°. The rake and angle should be zero to scrape, and not cut.
60
What calculation must be made when bending sheet metal?
Bend allowance and setback.
61
What must be done when two bends intersect?
Relief holes are drilled at the intersection.
62
What methods are used in forming sheet metal?
Shrinking, stretching, bumping, crimping, and folding.
63
What factors are used to determine 'setback'?
The radius of the bend and the thickness of the material.
64
What is the purpose of lightning holes cut in rib sections?
To reduce weight.
65
What is joggle?
It is the offset formed on a part to allow clearance for a sheet or another mating part.
66
How do you determine the total length of a solid rivet for installation?
Grip length plus 1.5 times the shank diameter.
67
How do you determine the proper material to be used for the repair of an all-metal aircraft?
Use the same type and thickness of material that was used in the original structure.
68
What is the single-row spacing and edge distance for protruding head rivets?
Edge distance is two times the diameter; spacing is three times the diameter.
69
Describe rivet head markings for A, B, D, AD, and DD rivets.
A - Plain (1100)
B - Cross (5056)
D - Tit (2024)
AD - Dimple (2117)
DD - Double Dash (2017)
70
Describe the criteria for the replacement of a 2024 rivet with a 2117 rivet for general repair.
For 5/32 or less diameter, use the next larger size rivet (2117), assuming that spacing and edge distance meet minimum requirements.
71
What is the preferred method of welding magnesium?
Gas shielded arc welding.
72
What is a safety hazard associated with welding magnesium?
If ignited, it is extremely hard to extinguish.
73
What must be done in the weld zone to successfully weld titanium?
The weld zone must be shielded with an inert gas.
74
Why is it necessary to use flux in all silver soldering?
To have the base metal chemically clean without the slightest film of oxide.
75
What type of flame is used for silver soldering?
A soft, neutral, or slightly reducing flame.
76
What type of repair could be made for a dented steel tube cluster joint?
Weld a formed steel patch plate over the dented area.
77
What are the three general types of welding?
Gas, electric arc, and electric resistance.
78
How is a soft flame obtained without reducing thermal output?
By using a larger tip and adjusting the pressures.
79
What is the most extensively used method of welding aluminum?
Gas-shielded arc welding.
80
What valve should be turned off first when extinguishing a torch?
The acetylene allows gas in the tip to burn out.
81
What procedure will control expansion when welding a joint?
Tack welding at intervals along the joint.
82
What safety precautions should be taken when gas welding has been completed?
Turn off the valves and relieve all pressure.
83
What must be done with heat-treated aluminum alloys after a welding repair has been made?
They must be reheat-treated.
84
What is the result of insufficient penetration?
A low-strength weld.
85
What is gas-shielded arc welding?
A gas is used as a shield around the arc to prevent the atmosphere from contaminating the weld.
86
What does the size of the torch tip opening determine?
The amount of heat, not the temperature.
87
What is used to inflate a landing gear shock strut?
Dry air or nitrogen.
88
What is the purpose of the main landing gear torque links?
They keep the landing gear pointed in a straight-ahead direction.
89
What power sources are normally used to retract landing gear systems?
Hydraulic or electrical.
90
What type of nose wheel steering is provided on small aircraft?
A simple system consisting of a mechanical linkage hooked to the rudder pedals.
91
What unit prevents nose wheel vibration?
A shimmy damper.
92
What are some types of brake actuating systems?
Independent, booster, and power control.
93
What is the purpose of power brake Debooster cylinders?
They reduce the pressure on the brakes and increase the volume of fluid flow.
94
What must be accomplished before inspecting a wheel brake system for hydraulic leaks?
Pressurize the system.
95
What prevents a split wheel from leaking air through the inner and outer mating surfaces, or the wheel assembly?
A rubber packing between the two assemblies.
96
What is the most necessary maintenance function for safe, long aircraft tire service?
Proper inflation.
97
What are the effects of underinflation on tires?
Rapid or uneven wear near the edge of the tread, and creep or slip when the brakes are applied.
98
When should a landing gear retraction check be accomplished?
During an annual inspection (or other inspections), when landing gear components have been replaced, and after hard landings.
99
What is the indication of excessive heating of a wheel bearing?
Discoloration, a bluish tint to the metal surface.
100
What is the purpose of an anti-skid system?
To bring a fast-moving aircraft to a stop during ground roll without tire skidding.
101
What is the purpose of a wheel fusible plug?
To relieve air pressure to prevent a tire blowout.
102
What are some methods of bleeding brakes?
Gravity and pressure methods.
103
What methods are used for transmitting cockpit control movements to a steering control unit in large aircraft?
Mechanical, electrical, or hydraulic.
104
What prevents a nose landing gear from being retracted with the nose wheel out of the center position?
Nose Wheel centering internal cams or external track.
105
What are the three types of hydraulic fluids?
Minerals, Polyalphaolefins, and Phosphate esters.
106
What color is mineral-based hydraulic fluid?
Red.
107
What happens to plastic resins, vinyl compositions, lacquers, and oil-based paints if they are exposed to a phosphate ester-based hydraulic fluid such as Skydrol?
The material will be damaged, softened, and/or peeled.
108
What feature is built into a hydraulic pump-drive system to prevent engine damage in the event of pump seizure or overload?
A shear section in the pump-drive shaft.
109
What precautions should be taken to minimize contamination during the replacement of a hydraulic unit?
All lines should be plugged or capped after disconnecting.
110
What would cause a hydraulic filter to go into an open bypass, allowing unfiltered fluid into the system?
A clogged filter.
111
How does a gear-type power pump operate?
Two meshed gears revolve in a housing and are driven by a power unit. Fluid is trapped and pressurized as the gears turn.
112
What are the two types of engine-driven hydraulic pumps?
Constant delivery and variable delivery.
113
What is the purpose of a pressure relief valve?
To limit the amount of pressure, thereby preventing failure of the system components.
114
What is the purpose of a pressure regulator?
To manage the output of the pump to maintain system pressure and allow the pump to turn without resistance (unloading).
115
What is used in some hydraulic systems to supplement the power pump when several units are operated at the same time?
An accumulator.
116
What are the different types of accumulators?
Spherical and cylindrical.
117
For what purposes are pneumatic systems used in some aircraft?
To operate brakes, doors, drive pumps, and engine starting.
118
What are the sources of pneumatic power?
Storage bottles, vane-type pumps, and turbine engine compressors.
119
What happens to excessive pressure in a pneumatic system?
A relief valve will bleed it into the atmosphere.
120
What is the purpose of restrictors that are used in aircraft pneumatic systems?
To control the rate of airflow.
121
Why should a pneumatic system be purged periodically?
To remove contamination and moisture.
122
What must be accomplished with any accumulator before disassembling?
Make sure the air or preload has been discharged.
123
What are the two groups of independent cabin compressors?
Positive-displacement and centrifugal.
124
What is the principal control of a pressurization system?
An outflow valve.
125
What method is used by some turbine-powered aircraft for pressurization?
Bleed air from the turbine-engine compressor.
126
What is a roots blower?
An engine-driven compressor.
127
What pressurization control unit will change the position of an outflow valve?
The cabin pressure controller.
128
What is the function of ventilating air in a combustion heater?
It is the air that is warmed and sent into the cabin.
129
What are the sources of ventilating air in a combustion heater?
A blower/fan or ram air.
130
What components are used in an air-cycle cooling system?
An expansion turbine, an air-to-air heat exchanger, and various valves.
131
What causes a temperature drop in the air-cycle cooling system?
The compressed air performs the work of turning a turbine, and it undergoes a pressure and temperature drop.
132
How does a water separator remove moisture from the air?
The moist air passes through vanes that swirl the air, and the droplets are collected and drained.
133
What is vapor-cycle cooling?
A closed system in which a refrigerant is circulated through the tubing and a variety of components to remove heat from the aircraft.
134
What components are in a vapor-cycle cooling system?
A receiver dryer, evaporator, compressor, condenser, and expansion valve.
135
How does a continuous-flow oxygen system operate?
Oxygen flows from a charged cylinder through a high-pressure line to a reducing valve and to mask outlets.
136
How does a basic pressure-demand oxygen system operate?
Oxygen flows from a charged cylinder to a pressure-demand regulator, adjustable by each crew member.
137
What must be accomplished if an oxygen system has been open to the atmosphere for 2 hours or more?
The system must be purged to remove moisture.
138
What is used to purge oxygen lines of moisture?
Dry nitrogen, dry air, or oxygen.
139
What type of oxygen must be used in aircraft?
"Aviator’s breathing oxygen."
140
Why is oil added to a vapor-cycle Freon system?
To seal and lubricate the compressor.
141
What safety precautions should be observed when servicing oxygen systems?
Clean, grease-free tools, clothing, and hands; no smoking near open flames within 50 feet; do not use adhesive tape of any kind.
142
What is used as a reference for range marking instruments?
Aircraft specification or type certificate data sheets, and flight manuals.
143
What does a yellow arc on an instrument dial indicate?
Caution
144
Why are slippage marks used on instrument glass covers?
To indicate glass rotation in the bezel.
145
When range markings are placed on an instrument glass, what precaution must be taken?
The glass must be marked for slippage indication.
146
What can be used to static check a manifold pressure indicator?
Current atmospheric pressure.
147
What indications of errors may be found in altimeters?
Scale, hysteresis, and installation.
148
What flight instruments are usually connected to a pitot-static system?
Rate of climb, airspeed, and altimeter.
149
What is required after the replacement of components connected to a pitot-static system?
A leak test.
150
What methods are used to drive turn-and-bank/ slip indicators?
Vacuum, air pressure, or electricity.
151
What causes an electric-driven gyro rotor to tilt when the aircraft is turned?
Gyroscopic precession.
152
What is a synchro-type remote indicating system?
A system that transmits information from one point to another point (flap position).
153
What does a tachometer indicate?
Crankshaft or main turbine rotor speed.
154
Where does an electrical resistance temperature indicator receive a signal?
From a temperature-sensitive element (or bulb).
155
What type of indicating system is a turbine engine exhaust gas temperature system?
A thermocouple-type system.
156
What is the meaning of swinging a compass?
Correcting for deviations by adjusting the compensating magnets.
157
Name at least two items that should be looked for during an inspection of a magnetic compass.
Security of attachment and the scale should be readable.
158
What are the three basic autopilot components?
Sensing elements (Gyros), output elements (Servos), and command elements (Flight Controller).
159
What are the sensing elements of an autopilot system?
A directional gyro, turn-and-bank gyro, attitude gyro, and altitude control.
160
What are the actuating (output) elements of an autopilot system?
Servos that operate the control surfaces.
161
What is the most common communication system in use?
Very high frequency (VHF) system.
162
How often does the ATC transponder require certification?
Every 24 calendar months.
163
What are the components of a typical airborne VOR system?
A receiver, a visual indicator, a frequency selector, antennas, and a power supply.
164
Why are two antennas or a single multi-element antenna usually required for an ILS system?
One for the localizer, and one for the glide slope receivers.
165
What information does a glide slope radio beam provide?
Vertical guidance for the correct angle of descent.
166
What is a DME?
Distance measuring equipment.
167
What is VOR equipment used for?
Navigation.
168
Where should DME antennas be located?
On the lower surface of the aircraft fuselage, the centerline.
169
What is an ADF?
An automatic direction finder.
170
What powers an emergency locator transmitter (ELT)?
A self-contained battery.
171
What is one method used to monitor the output signal during an ELT test?
A VHF communications receiver tuned to 121.5 MHz.
172
How may the determination be made to replace or recharge the batteries in an ELT even though the set operates?
The expiration date for replacing or for recharging is marked on the outside of the transmitter and entered in the aircraft maintenance record.
173
How does bonding help reduce radio interference?
By providing a low-impedance ground return.
174
What time of day should you perform the maintenance tests of an installed ELT?
The test should be conducted during the first 5 minutes after the hour; at any other time, it should be coordinated with the nearest Control Tower or Flight Service Station.
175
What is the purpose of a fuel jettisoning (dump) system?
To reduce the weight of the aircraft to a specified landing weight.
176
When would a fuel jettison system be required for small aircraft?
It is required when the maximum takeoff weight exceeds the maximum landing weight.
177
What are the two types of fuel tanks (cells)?
A bladder-type fuel tank and an integral fuel tank.
178
What supports the weight of fuel in a bladder-type fuel cell?
The structure of the cavity that the cell fits into.
179
What is wet wing-type construction?
Integral fuel tanks.
180
What indicators could be used to determine when there may be a danger of ice crystals forming in the fuel of a turbine-powered aircraft?
Fuel temperature or differential pressure type indicators.
181
What is an electrically operated fuel tank shutoff valve in a transit light?
A light that indicates when the valve is in motion.
182
What is the pressure fueling system sometimes referred to as?
Single-point fueling system.
183
What method may be used to check a fuel tank for leaks after a weld has been performed?
The tank is pressurized with ½ to 3 psi air pressure, and a soapy solution is added to detect any leaks.
184
What should be done with old gaskets and seals when replacing fuel system components?
They should be removed and replaced with new ones.
185
What are the four types of fuel quantity gauges in use today?
Sight glass, mechanical, electrical, and electronic.
186
What is the purpose of fuel tank internal baffles?
To resist fuel surging caused by changes in the attitude of the aircraft.
187
Why should you wait a period after fueling before checking fuel sumps?
To allow time for water and sediment to settle at the drain point.
188
What type of circuit breaker should not be used in aircraft?
Automatic reset-type circuit breakers.
189
When should a switch be derated from its nominal rating?
When used with high rush-in circuits, inductive circuits, and direct current motors.
190
Where is the white position/navigation light mounted?
On the tail, visible from the rear.
191
What factors are considered when selecting wire size for electrical power?
Allowable power loss, permissible voltage drop, and current carrying ability.
192
When do D.C. motors draw several times their rated current?
When starting.
193
How long should bonding jumper wires be?
As short as practicable.
194
What hardware is used to make bonding or grounding connections to a structure of dissimilar material?
A washer of suitable material should be used so that corrosion will occur on the washer.
195
What should be done to the conduit end when fittings are not used?
It should be deburred to prevent wire insulation damage.
196
What size electrical conduit should be used?
25% larger than the maximum diameter of the wire bundle.
197
When is a circuit breaker designed to open?
When an overload or circuit fault exists.
198
What controls the output voltage of an alternator?
A Generator Control Unit (GCU).
199
How many terminal lugs can be put on a single terminal strip in an aircraft?
Four.
200
How can a particular wire in a bundle be identified?
By the identification code on the wire.
201
What types of landing gear warnings are provided for retractable landing gear systems?
A horn or some other aural device and a red warning light.
202
When does an aural device operate in a landing gear warning system?
When the throttle is retarded and the landing gear is not down and locked.
203
What is the purpose of a Mach warning system?
It provides an aural warning that aircraft speed limits have been exceeded.
204
How does a takeoff aural warning differ from a landing gear aural warning?
The aural horn for takeoff is intermittent and continuous for landing.
205
Name at least two items that may cause a takeoff warning horn to operate in a typical transport jet aircraft.
Speed brake and flaps.
206
When should landing gear switches, lights, and warning horns or buzzers be checked for proper operation?
During a gear retraction check.
207
What retractable landing gear positions must be indicated?
Secured in the up position and secured in the down position.
208
Where are the procedures located for checking and adjusting landing gear switches?
The aircraft manufacturer's manual.
209
What other aircraft systems may activate the landing gear warning system?
The wing flaps system.
210
What is the reason for a master caution warning system in aircraft?
To draw the attention of the crew to a critical situation, in addition to an annunciator that describes the problem.
211
What system is used to indicate battery overtemperature?
A warning light.
212
What is the purpose of the annunciator system?
To display current conditions and to notify of unsatisfactory conditions.
