Airframe Flashcards
1
Q
For maximum strength of a formed sheet metal fitting, should the bend be made along or across the grain of the metal?
A
Across the grain
2
Q
What determines the minimum bend radius that can be used when forming a sheet metal structural fitting?
A
Alloy
Metal thickness
Hardness
3
Q
What is meant by the neutral axis in a sheet of metal?
A
A plane within the metal that neither stretches nor shrinks when the metal is being bent
4
Q
What is a mold line in the development of a flat pattern for a formed metal part?
A
An extension of the flat sides beyond the radius
5
Q
What is the bend tangent line?
A
A line in a flat pattern layout at which the bend starts
6
Q
What is meant by setback?
A
The distance the jaws of a brake must be set back from the mold line to form a bend
7
Q
What is meant by bend allowance?
A
The actual amount of metal in a bend. it is the distance between the bend tangent lines in a flat pattern layout
8
Q
What is a sight line?
A
A line drawn on a flat pattern layout within the bend allowance that is one bend radius from the bend tangent line. When the sight line is directly below the nose of the radius bar on the brake, the bend will start at the bend tangent line
9
Q
What is the main function of throatless shears in an aircraft sheet metal shop?
A
Throatless shears are used to cut mild carbon steel up to 10-gauge, and stainless steel up to 12-gauge. They can be used to cut irregular curves in the metal.
10
Q
What kind of metal forming is done by a slip roll former?
A
Simple curves with a large radius.
11
Q
What kind of metal forming is done by bumping?
A
Compound curves in sheet metal.
12
Q
When forming a curved angle, what must be done to the flanges?
A
The flanges must be stretched for a convex curve and shrunk for a concave curve
13
Q
When hand-forming a piece of sheet metal that has a concave curve, should the forming be started in the center of the curve, or at its edges?
A
Start at the edges and work toward the center
14
Q
What is meant by a joggle in a piece of sheet metal?
A
A joggle is a small offset near the edge of a piece of sheet metal that allows the sheet to overall another piece of metal
15
Q
What is another name for GTA welding?
A
TIG welding
16
Q
What is used as the electrode in GTA welding?
A
A small-diameter tungsten wire
17
Q
What are three types of power that can be used for GTA welding?
A
DC-straight polarity
DC-reverse polarity
AC
18
Q
Which type of power provides the greatest heat and deepest penetration in GTA welding?
A
DC-straight polarity
19
Q
Which type of power is used for GTA welding aluminum and magnesium?
A
DC-reverse polarity
20
Q
What effect does moisture have on a wood aircraft structure?
A
Moisture causes the wood to swell and crack as it dries out. It allows fungus to develop in the wood and cause it to decay.
21
Q
What type of nondestructive inspection is suitable for detecting internal damage in honeycomb material?
A
Ultrasonic inspection
22
Q
What is the simplest way to detect delamination in a composite structure?
A
Tap the surface with the edge of a coin. If the material is sound, the tapping will result in a clear ringing sound; but if it is delaminated, the sound will be a dull thud.
23
Q
Of what class of resins are aircraft windows and windshields made?
A
Thermoplastic
24
Q
What is meant by crazing of a transparent plastic material?
A
Tiny hair-like cracks that may not extend all of the way to the surface. Crazing is caused by stresses or chemical fumes.
25
If a mechanic gives a 100-hour inspection to an aircraft that proves to be unairworthy, what must the mechanic give the owner or operator of the aircraft?
A signed and dated list of all of the discrepancies that keep the aircraft from being airworthy
26
Where can you find the recommended statement to use for recording the approval or disapproval of an aircraft for return to service after a 100-hour inspection?
In 14 CFR 43.11
27
Under what conditions can an aircraft be operated with a 100-hour inspection overdue?
The aircraft can be operated for no more than 10 hours after an inspection is due for the purpose of flying it to a place where the inspection can be performed.
28
For how long can an aircraft be operated if a 100-hour inspection is overdue?
For no more than 10 hours. The time beyond the 100 hours must be subtracted from the time before the next inspection is due.
29
Under what conditions can an aircraft that is due for an annual inspection be operated?
It can only be flown when a special flight permit is issued
30
What certification is required for a mechanic to be able to approve an aircraft for return to service after a 100-hour inspection?
An aviation Mechanic certificate with Airframe and Powerplant ratings
31
What determines whether or not an aircraft must be given a 100-hour inspection?
Aircraft that carry persons for the hire and aircraft that are used for flight instruction for hire must be given 100-hour inspections
32
What is the difference between an annual inspection and a 100-hour inspection?
An annual inspection can be conducted only by an A&P mechanic who holds an inspection Authorization, while a 100-hour inspection can be performed by an A&P mechanic without an IA. (The inspections themselves are identical)
33
What certification is required for a mechanic to conduct an annual inspection and approve the aircraft for return to service after the inspection?
An aviation Mechanic certificate with Airframe and Powerplant ratings and an Inspection Authorization
34
What is progressive inspection?
An inspection of the same level as an annual inspection but approved by the FAA to be performed on a schedule that does not require the aircraft to be out of service for the time necessary to perform the entire inspection all at once
35
What certification is required for a mechanic to conduct a progressive inspection?
An Aviation Mechanic certificate with Airframe and Powerplant ratings and an Inspection Authorization
36
Where can you find the requirements for inspecting the altimeter and static systems of aircraft operated under instrument flight rules?
In 14 CFR Part 43, Appendix E
37
Where can you find the requirements for inspecting the ATC transponder that is installed in an aircraft?
In 14 CFR Part 43, Appendix F
38
What items must be inspected on a helicopter in accordance with the instructions for Continued Airworthiness?
The drive shafts or similar systmes
The main rotor transmission gear box
The main rotor and center section
The auxiliary rotor
39
Where may a list of the approved lubricants for greasing an aircraft retractable landing gear be found?
In the aircraft maintenance manual
40
Where can you find the specifications for the type of fluid used to service an aircraft landing gear shock strut?
On the nameplate on the strut
41
How much oil should be put into an oleo shock strut?
With the strut completely deflated, fill it to the level of the filler plug
42
What kind of filter is a micronic filter?
A filter with a special paper element
43
What is a double-action pump?
A pump that delivers fluid with the movement of the pump handle in both directions
44
Why do most engine-driven hydraulic pumps have a shear section in their drive couplings?
If the pump should seize, the shear section will break, disconnecting the pump from the engine and preventing further damage
45
What are the two basic types of hydraulic fluid used in modern aircraft?
Mineral base fluid and phosphate ester base fluid
46
Does the main hydraulic pump take its fluid from the bottom of the reservoir, or from a standpipe?
The main pump normally takes its fluid from a standpipe, while the emergency pump takes its fluid from the bottom of the reservoir. If a break in the system should allow the main pump to pump all of its fluid overboard, there will still be enough fluid in the reservoir to allow the emergency system to extend the landing gear and actuate the brakes.
47
Why are some hydraulic reservoirs pressurized?
Pressurization ensures that fluid will be supplied to the inlet of the pumps at high altitude where there is not enough atmospheric pressure to do this
48
What are two ways aircraft hydraulic reservoirs may be pressurized?
By an aspirator in the fluid return line or by bleed air from one of the engine compressors
49
What is used to flush a hydraulic system that uses Skydrol hydraulic fluid?
Trichloroethylene or the solvent recommended by the aircraft manufacturer
50
What is used to flush a hydraulic system that uses mineral base hydraulic fluid?
Naphtha
Varsol
Stoddard solvent
51
Where can you find the type of hydraulic fluid required for a particular aircraft?
In the maintenance manual for the aircraft. This information is also on a placard on the system reservoir
52
What type of pump is a gear pump considered?
A gear pump is a constant displacement, high pressure pump.
53
What type of pump is a piston pump with a variable cam plate considered?
Fuel pumps may be divided into two distinct system categories:
1. constant dispalcement
2. variable displacement
A piston pump with a variable cam changes the effective (not actual) length of each piston stroke. This makes this type of pump a variable displacement with constant pressure.
54
Is a chevron seal a one-way or a two-way seal?
A one-way seal
55
To which side of a chevron seal should the pressure be applied?
To the open side
56
Is an O-ring seal a one-way or a two-way seal?
A two-way seal
57
How can you be sure of getting an O-ring made of the correct material for a specific hydraulic component?
The O-ring must have the correct part number and it must have been obtained from a reputable source
58
On which side of an O-ring should the backup ring be placed?
On the side away from the source of pressure
59
What should be done to the sharp edges of threads and actuator pistons when installing O-rings?
The sharp edges should be covered with paper
60
How is the heat removed from an aircraft cabin with a vapor-cycle air conditioning system?
The cabin heat is absorbed by the refrigerant in the evaporator, then carried outside the aircraft where it is given up to the outside air in the condenser
61
What produces the cool air in a vapor-cycle air conditioning system?
A Freon-type liquid refrigerant known as Refrigerant 12, or the more environmentally friendly R-134a.
62
What is the state of the refrigerant as it leaves the compressor?
It is a high-pressure gas
63
What is the state of the refrigerant as it leaves the condenser?
It is a high-pressure liquid.
64
What is the state of the refrigerant as it leaves the thermostatic expansion valve?
It is a low-pressure liquid
65
What is the state of the refrigerant as it leaves the evaporator?
It is a low-pressure vapor
66
How is the compressor lubricated?
Refrigeration oil is mixed with the refrigerant and it circulates through the compressor and the entire system.
67
What is the function of the thermostatic expansion valve?
It meters just enough liquid refrigerant into the evaporator that all of it will be evaporated by the time it leaves the evaporator coils
68
How is refrigerant put into the system?
Through the service valves on the low side of the system using a manifold gauge set
69
How should the components in the low side of a properly operating vapor-cycle cooling system feel?
They should feel cool
70
How is a vapor-cycle cooling system checked for refrigerant leaks?
Hold the probe of an electronic leak detector below any suspect fitting or component. If there is aleak, the tone of the sound produced by the detector will change
71
What safety equipment should be worn when charging a vapor-cycle cooling system?
A safety face shield that protects the entire face
72
What are two types of air conditioning systems that may be installed on an aircraft?
Air-cycle systems
Vapor-cycle systems
73
What is the preferred location for the ATC transponder antenna?
On the center line of the belly of the aircraft as far from any other antenna as is practical
74
What are the three basic types of antennas used in aviation?
Dipole antenna
Marconi antenna
Loop antenna
75
What type of antenna are most aircraft VHF communication antennas?
Marconi antennas
76
How do static wicks aid the aircraft communication radios?
Static wicks aid in the dissipation of static that builds up on the aircraft. Built-up static can cause radio receiver interference caused by corona discharge emitted from the aircraft as a result of precipitation static.
77
What is the basic purpose of an autopilot?
It frees the human pilot from continuously having to fly the aircraft, and flies with a high degree of precision. It also couples with various electronic navigational aids.
78
What are the basic subsystems of an automatic flight control system?
Command
Error-sensing
Correction
Follow-up
79
What type of device is normally used in the error-sensing subsystem?
Gyros
80
What are three types of servos that are used in the correction subsystem?
Hydraulic
Pneumatic
Electric
81
What is the purpose of the follow-up subsystem in an autopilot?
It stops the control movement when the surface has deflected the proper amount for the signal sent by the error sensor
82
Where can you find the correct part number for the fuel quantity sensor to be installed in an aircraft fuel tank?
In the Illustrated Parts Catalog for the aircraft
83
Where are fuel system strainers located?
One strainer is located in the outlet to the tank, and the main strainer is located in the fuel line between the outlet of the fuel tank and the inlet to the fuel metering device
84
Why do the fuel strainers used on some turbine-engine aircraft have a warning device that signals the flight crew when the strainer is beginning to clog up?
Strainers clog because ice forms on the filter element. The flight crew can route the fuel through a fuel heater to melt the ice
85
How does water appear in the fuel drained from the tank sumps?
Water appears as a clear globule in the bottom of the container used to collect the fuel drained from the sumps
86
Why must an aircraft fuel valve have a detent in its operating mechanism?
The detent gives the pilot a positive indication by feel when the selector valve is in the full ON and full OFF position
87
What must be done before a fuel selector valve can be removed from an aircraft?
The tank to which the valve is connected must be drained or otherwise isolated
88
What must be done after a fuel valve is replaced?
The fuel system must be checked for leaks
89
Why are fuel tanks divided into compartments or have baffles installed in them?
The compartments or baffles keep the fuel from surging back and forth as the aircraft changes its altitude in flight
90
How is a fuel leak indicated on a reciprocating-engine-powered aircraft?
The dye in the gasoline stains the area around the leak
91
What is the function of the sump in a fuel tank?
The sump, or lowest point, in a fuel tank is located below the fuel outlet. The sump collects water and contaminants and will have a drain to remove them
92
What are the three different types of fuel tanks?
Built-up tanks
Integral tanks
Bladder tanks
93
What problem can occur in a bladder tank with a blocked vent?
As internal tank pressure decreases, the pressure differential between the atmosphere and the tank can cause the tank restraints to fail and the tank can collapse and block the fuel outlet
94
How do you prepare an aluminum fuel tank for welding?
Remove all fuel and thoroughly wash the tank, inside and out, with hot water and detergent. The tank should be purged with live steam for at least 30 minutes to remove all residual fuel and vapors.
95
After welding an aluminum fuel tank, to what pressure should the tank be tested?
3.5 PSI
96
What color is grade 100-LL fuel?
Blue
97
How can you detect jet fuel in the sample taken from the tank sump drains?
Jet fuel is basically clear and it has an odor similar to kerosine
98
What size generator must be used in an aircraft electrical system if the connected electrical load is 30 amps, and there is no way of monitoring the generator output?
When monitoring is not practical, the total continuously connected electrical load must be no more than 80% of the rated generator output. This would require a generator with a rating of 37.5 amps. Practically, a 40-amp generator would be installed
99
What is meant by "flashing" the field of a generator?
Restoring the residual magnetism to the frame of the generator. This is done by passing battery current through the field coils in the direction it normally flows when the generator is operating
100
What is meant by paralleling the generators in a multi-engine aircraft?
Adjusting the voltage regulators so all the generators share the electrical load equally
101
What are the three types of voltage regulators used with aircraft generators?
Vibrator type
Carbon-pile type
Solid state type
102
How many electrical phases are in aircraft alternators?
3
103
What is the advantage of using AC power over DC power?
AC voltages can be stepped up to higher voltages, which means that current goes down and smaller wires can be used to save weight. The voltage is stepped back down at the point of use
104
What is the frequency of AC voltage used in aircraft?
400 Hz
105
How does a constant speed drive (CSD) unit maintain a constant output frequency of the AC generator?
By maintaining a constant speed of the generator as the engine speed varies
106
What is an integrated drive generator (IDG)?
When a constant speed drive (CDG) is combined within the alternator housing, the assembly is known as an IDG
107
Where could you find the part number of a switch in an aircraft electrical system?
In the equipment table or bill of materials on the electrical circuit diagram for the aircraft
108
What is the main disadvantage of aluminum wire over copper wire for use in an aircraft electrical system?
Aluminum wire is more brittle than copper. It is more subject to breakage when it is nicked or when it is subjected to vibration
109
What size aluminum wire would be proper to replace a piece of four-gauge copper wire?
Two-gauge. When you substitute aluminum wire for copper wire, use a wire that is two gauge numbers larger
110
What is the smallest size aluminum wire that is approved for use in aircraft electrical systems?
Six-gauge
111
Can you substitute aluminum wire for copper wire?
Yes. However, you must use aluminum wire two wire gauge sizes larger to carry the same current. Aluminum wire should never be used in runs of three feet or less, or in communication and navigation systems.
112
Can wire in free air carry the same current as wire in a bundle?
Wire in free air may be used to a higher current level than the same size wire in a bundle. Always refer to an electrical wire size selection chart.
113
What are common causes of wire failure in a crimped connector?
The wire was not inserted far enough into the connector and/or the connector was excessively crimped
114
What is one of the first things to check if an electrical component does not operate?
Always start with simple solutions and move to more complex.
Is the component turned on?
Is power available?
115
What may be provided by the manufacturer to assist in troubleshooting?
Manufacturers often provide a troubleshooting logic chart
116
What are the four basic steps of troubleshooting?
Know how the system should operate
Observe the way the system is operating
Divide the system into smaller segments to isolate trouble
Look for the obvious problem first
117
When routing a fluid line parallel to an electrical wire bundle, which should be on top?
The electrical wire bundle should be on top
118
What does the specific gravity of the electrolyte of a lead-acid aircraft battery indicate?
The amount of acid relative to the water in the electrolyte. This is an indication of the state of charge of the battery
119
What are the most likely causes of a battery with a distorted or swollen battery case?
The battery has been overcharged or over-discharged, causing overheating, or it could be caused by a plugged vent cap
120
On NiCd batteries, what is the minimum cell voltage at the end of the charge cycle?
1.55 volts
121
How is the state of charge determined on NiCd battery?
The only accurate way to determine the state of charge of NiCd battery is by a measured discharge with a NiCd battery charger and following the manufacturer's instructions.
