Chapter 7 Section C FAA Questions

7-66 AMA042

Electric wire terminals for most aircraft applications must be what type?

A— Ring.

B— Hook.

C— Slotted.

7-66. Answer A. JSAT 7C

The ring-type terminal is less likely to fail than slide-on type terminals.

7-67 AMA041

The type of electric wire terminals used for most aircraft applications, in addition to providing good current carrying capabilities, are designed primarily

A— to prevent circuit failure due to terminal disconnection.

B— for permanent connection to the circuit.

C— for uncomplicated and rapid circuit connection and disconnection.

7-67. Answer A. JSAT 7C

Ring-type terminals are used because they are less likely to fail, causing a circuit interruption.

7-68 AMA041

Aluminum wire must be stripped very carefully because

A— high resistance will develop in stripping nicks.

B— stripping nicks can cause short circuits.

C— individual strands will break easily after being nicked.

7-68. Answer C. JSAT 7C, FAH

Aluminum wire must be stripped very carefully, using extreme care, because individual strands will break very easily after being nicked.

7-69 AMA041

For general electrical use in aircraft, the acceptable method of attaching a terminal to a wire is by

A— crimping.

B— soldering.

C— crimping and soldering

7-69. Answer A. JSAT 7C

A properly installed crimp-on terminal will be at least as strong as the wire itself. Soldering makes a wire more rigid and more likely to break at the terminal.

7-70 AMA042

Which of the following factors must be taken into consideration when determining the wire size to use for an aircraft installation?

1. Mechanical strength.

2. Allowable power loss.

3. Ease of installation.

4. Resistance of current return path through the aircraft structure.

5. Permissible voltage drop.

6. Current carrying capability of the conductor.

7. Type of load (continuous or intermittent).

A— 1, 2, 4, and 5.

B— 2, 4, 6, and 7.

C— 2, 5, 6, and 7.

7-70. Answer C. JSAT 7C, FAH

Several factors must be considered in selecting the size of wire for transmitting and distributing electrical power. They are the allowable power loss, permissible voltage drop in the line, the current-carrying ability of the conductor, and whether or not the load is continuous or intermittent.

7-71 AMA042

When selecting hardware for attaching bonding connections to an aircraft structure, which of the following should be considered?

1. Mechanical strength.

2. Allowable power loss.

3. Ease of installation.

4. Permissible voltage drop.

5. Amount of current to be carried.

6. Type of load (continuous or intermittent).

A— 1, 3, and 5.

B— 1, 2, and 3.

C— 4, 5, and 6.

7-71. Answer A. JSAT 7C, FAH
Hardware used to make bonding or grounding connections should be selected on the basis of mechanical strength, the current to be carried, and ease of installation.

7-72 AMA041

How should the splices be arranged if several are to be located in an electrical wire bundle?

A— Enclosed in a conduit.

B— Grouped together to facilitate inspection.

C— Staggered along the length of the bundle.

7-72. Answer C. JSAT 7C, AC 43.13-1B

Stagger splices so the bundle doesn’t become too large.

7-73 AMA041

What is the minimum bend radius for an electrical wire bundle?

A— Ten times the outside diameter of the bundle.

B— Fifteen times the outside diameter of the bundle.

C— Five times the outside diameter of the bundle.

7-73. Answer A. JSAT 7C, AC 43.13-1B

Avoid a bending radius of less than 10 times the outer diameter of the bundle.

7-74 AMA042

When approved, splices may be used to repair manufactured harnesses or installed wiring. The maximum number of splices permitted between any two connectors is

A— three.

B— two.

C— one.

7-74. Answer C. AC 43.13-1B

Splices should be kept to a minimum and avoided entirely in areas subject to extreme vibrations.

7-75 AMA041

AN/MS electrical connectors are specifically designed to meet

A— International Civil Aviation Organization (ICAO) standards.

B— Technical Standard Order (TSO) specifications.

C— military specifications

7-75. Answer C. JSAT 7C

AN (Air Force-Navy) and MS (Military Standards) are both hardware identification systems originating in the military.

7-76 AMA041

The most common method of attaching a pin or socket to an individual wire in an MS electrical connector is by

A— crimping and soldering.

B— crimping.

C— soldering.

7-76. Answer A. JSAT 7C

Earlier versions of AN/MS connectors used solder to connect each wire to its pin or socket. Newer connectors used crimp-type terminations.

7-77 AMA041

The pin section of an AN/MS connector is normally installed on

A— either side of a circuit (makes no difference).

B— the ground side of a circuit.

C— the power supply side of a circuit.

7-77. Answer B. JSAT 7C

To eliminate possible short circuits to ground, the end of the connector that carries the power uses socket connectors.

7-78 AMA042

If several long lengths of electrical cable are to be installed in rigid conduit, the possibility of damage to the cable as it is pulled through the conduit will be reduced by

A— applying a light coat of dielectric grease.

B— dusting the cable with powdered graphite.

C— dusting the cable with powdered soapstone.

7-78. Answer C. JSAT 7C, FAH

Dusting of electrical cable with powdered soapstone prior to routing it through rigid conduit is advisable because the cable will have less tendency to bind or hang up. This will also reduce chafing or abrasion.

7-79 AMA042

What is normally used to bond noncontinuous stainless steel aircraft components?

A— Aluminum jumpers.

B— Stainless steel jumpers.

C— Copper jumpers.

7-79. Answer C. JSAT 7C, AC 43.13-1B, FAH

Aluminum alloy jumpers are recommended for most bonding connections. Copper jumpers, however, are used to bond together parts made of stainless steel, cadmium-plated steel, copper, brass, or bronze.

7-80 AMA042

Oil canning of the sides of aluminum or steel electrical junction boxes is considered to be

A— normal operation in vibration prone areas.

B— acceptable operation.

C— a shorting hazard.

7-80. Answer C. JSAT 7C

Junction boxes should be fabricated of such material, and installed in such a manner as to prevent oil-canning. Oil canning is considered a shorting hazard.

7-81 AMA041

Electric wiring installed in aircraft without special enclosing means (open wiring) offers the advantages of ease of installation, simple maintenance, and reduced weight. When bundling open wiring, the bundles should

A— be limited as to the number of cables to minimize damage from a single electrical fault.

B— include at least one shielded cable to provide good bonding of the bundle to the airframe.

C— be limited to a minimum bend radius of five times the bundle diameter to avoid excessive stresses on the cable insulation.

7-81. Answer A. JSAT 7C, AC 43.13-1B

When wire is being run in bundles, to simplify maintenance and to minimize the damage that may result from a single fault, the number of wires in the run should be limited.

7-82 AMA042

During inspection of the terminal strips of an aircraft electrical system, it should be determined that

A— only plain nuts and lockwashers have been used for terminal attachment to the studs.

B— only locknuts have been used for terminal attachment to the studs.

C— the terminal studs are anchored against rotation.

7-82. Answer C. JSAT 7C, FAH

Terminal lugs should be installed on terminal blocks so that they are locked against movement in the direction of loosening.

7-83 AMA041

What protection to wires and cables does conduit provide when used in aircraft installations?

A— Mechanical.

B— Structural.

C— Electromagnetic.

7-83. Answer A. JSAT 7C, FAH

Conduit is used in aircraft installations for the mechanical protection of wires and cables.

7-84 AMA041

Which of the following should be accomplished in the installation of aircraft wiring?

A— Provide adequate slack in the wire bundle to compensate for large changes in temperature.

B— Locate the bundle above flammable fluid lines and securely clamp to structure.

C— Support the bundle to structure and/or solid fluid lines to prevent chafing damage.

7-84. Answer B. JSAT 7C, AC 43.13-1B, FAH

Wiring must be routed at least six inches spacing above flammable-fluid lines whenever possible.

7-85 AMA041

Aircraft electrical junction boxes located in a fire zone are usually constructed of

A— stainless steel.

B— cadmium plated steel.

C— asbestos.

7-85. Answer A. JSAT 7C, AC 43.13-1B

When fire-proofing is necessary, a junction box made out of stainless steel is recommended.

7-86 AMA042

How does the routing of coaxial cables differ from the routing of electrical wiring?

A— Coaxial cables are routed parallel with stringers or ribs.

B— Coaxial cables are routed as directly as possible.

C— Coaxial cables are routed at right angles to stringers or ribs.

7-86. Answer B. JSAT 7C, FGH

All wiring should be installed so that it is mechanically and electrically sound and neat in appearance. Most electrical wiring should be routed parallel with, or at right angles to, aircraft structural members like stringers or ribs. An exception to this method of routing is coaxial cable, which is routed as directly as possible.

7-87 AMA042

Which of the following copper electrical cable sizes should be selected to replace a No. 6 aluminum electrical cable?

A— No. 6.

B— No. 8.

C— No. 4.

7-87. Answer B. JSAT 7C, AC 43.13-1B

Aluminum wire can be substituted for copper wire if the size of the wire is increased. Two sizes larger should be used when the substitution is made, but aluminum wire smaller than a number 6 should not be used. Remembered that, as the number gets smaller, the wire size gets larger. A number 10 copper wire could be substituted for a number 6 aluminum. No. 8 is the closest answer.

7-88 AMA042

Which statement relating to electric wiring is true?

A— When attaching a terminal to the end of an electric cable, it should be determined that the strength of the cable to terminal joint is at least twice the tensile strength of the cable.

B— All electric cable splices should be covered with soft insulating tubing (spaghetti) for mechanical protection against external abrasion.

C— When attaching a terminal to the end of an electric cable, it should be determined that the strength of the cable to terminal joint is at least equal to the tensile strength of the cable itself.

7-88. Answer C. JSAT 7C, AC 43.13-1B

Terminals are attached to the ends of electric wires to facilitate connection of the wires to terminal strips or items of equipment. The tensile strength of the wire to terminal joint should be at least equivalent to the tensile strength of the wire itself, and its resistance negligible relative to the normal resistance of the wire.

7-89 AMA042

Bonding connections should be tested for

A— reactance.

B— amperage value.

C— resistance value.

7-89. Answer C. JSAT 7C, AC 43.13-1B

When a bonding jumper is being made, it should be as short as practicable. It should be installed in such a manner that the resistance of each connection does not exceed .003 ohm.

7-90 AMA041

If it is necessary to use an electrical connector where it may be exposed to moisture, the mechanic should

A— coat the connector with grease.

B— spray the connector with varnish or zinc chromate.

C— use a special moisture proof type.

7-90. Answer C. JSAT 7C, FAH

Electrical connectors are particularly vulnerable to corrosion due to condensation which can collect in the shell. Special connectors with waterproof features have been developed which can be used to replace non-waterproof plugs in areas where moisture causes a problem.

7-91 AMA041

If a wire is installed so that it comes in contact with some moving parts, what protection should be given the wire?

A— Wrap with friction tape.

B— Pass through conduit.

C— Wrap with soft wire solder into a shield.

7-91. Answer B. JSAT 7C, AC 43.13-1B, FAH

If an electrical cable, wire bundle, or individual wire might come in contact with some moving part of the aircraft, the wire must be protected by passing it through conduit.

7-92 AMA042

In the American Wire Gauge (AWG) system of numbers used to designate electrical wire sizes, the number assigned to a size is related to its

A— cross sectional area.

B— combined resistance and current carrying capacity.

C— current carrying capacity.

7-92. Answer A. JSAT 7C, FAH

In the American Wire Gauge system, electrical wire size numbers relate to the cross-sectional area of the wire. The way the system works, however, the larger the wire size, the smaller the number size. For example, a number 8 wire is larger than a number 12 wire.

7-93 AMA042

What is the voltage drop for a No. 18 copper wire 50 feet long to carry 12.5 amperes, continuous operation?

Use the formula: VD = RLA; VD = Voltage drop; R = Resistance per ft = .00644; L = Length of wire; A = Amperes;

A— 1/2V.

B— 1V.

C— 4V.

7-93. Answer C. JSAT 7C, AC 43.13-1B

The values given in this question are plugged into the voltage drop formula as follows: Step 1: Resistance per foot (.00644) × 50 feet of wire = .322. Step 2: .322 × the current flow of 12.5 = 4.025 voltage drop.

7-94 AMA041

Where electric cables must pass through holes in bulkheads, formers, ribs, firewalls, etc., the wires should be protected from chafing by

A— wrapping with electrical tape.

B— using a suitable grommet.

C— wrapping with plastic.

7-94. Answer B. JSAT 7C, FAH

Wires and wire groups should be protected against chafing or abrasion in those locations where contact with sharp surfaces or other wires would damage the insulation. Damage to the insulation can cause short circuits, malfunction, or inadvertent operation of equipment. When wires are being passed through holes, it may be necessary to install a rubber grommet to protect the wire from any sharp edges.

7-95 AMA042

When considering an alteration, the criteria upon which the selection of electric cable size should be based are

A— current carrying capacity and applied voltage.

B— current carrying capacity and allowable voltage drop.

C— applied voltage and allowable voltage drop.

7-95. Answer B. JSAT 7C, FAH

The size of electric cable to use is determined by the amount of current it will be asked to carry and the amount of voltage drop which will be allowable.

7-96 AMA041

What is the maximum amount of time a circuit can be in operation and still be an intermittent duty circuit?

A— Two minutes.

B— One minute.

C— Three minutes.

7-96. Answer A. JSAT 7C

Intermittent duty circuits are those which are operated for only a few seconds or minutes and then are turned off. Examples include the landing gear, flaps, trim motors, landing lights, and emergency hydraulic pumps.