Aircraft Assembly and Rigging

Questions and Answers

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

Five times the outside diameter of the bundle.

Fifteen times the outside diameter of the bundle.

Ten times the outside diameter of the bundle. (correct)

What is a cause of generator brush arcing?

Low spring tension. (correct)

Seating brushes with No. 000 sandpaper. (correct)

Carbon dust particles. (correct)

What is the purpose of the selection of derated switches for known continuous load current applications?

To calculate the voltage drop across the circuit.

To obtain reasonable switch efficiency and service life. (correct)

To prevent short circuits in the motor field windings.

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

Locate the bundle above flammable fluid lines and securely clamp to structure. Signup and view all the answers

The navigation lights of some aircraft consist of a single circuit controlled by a single switch that has an ON position and an OFF position. What is this switch referred to as?

Single-pole, single-throw (SPST), two-position switch. Signup and view all the answers

Why are the iron cores of most induction coils laminated?

To reduce the effects of eddy currents. Signup and view all the answers

Which of the following types of instruments is used for measuring very high values of resistance?

Megohmmeter. Signup and view all the answers

What is the maximum amount of time a circuit can be in an open condition before it must be reset?

This is usually defined by the specific circuit's design and usage parameters, commonly found in aircraft documentation. Signup and view all the answers

What does a rectifier do?

Changes alternating current into direct current. Signup and view all the answers

The generator rating is usually found stamped on the firewall.

False Signup and view all the answers

The voltage output of an alternator may be regulated by controlling the _____ of the alternator.

speed Signup and view all the answers

The starting current of a series-wound DC motor produces a

Low starting torque Signup and view all the answers

The only practical method of maintaining a constant voltage output from an aircraft generator under varying conditions of speed and load is to vary the

Strength of the magnetic field Signup and view all the answers

Electric wiring installed in aircraft without special enclosing means offers advantages of ease of installation.

True Signup and view all the answers

What is most likely to cause thermal runaway in a nickel-cadmium battery?

Excessive current draw from the battery Signup and view all the answers

How can the direction of rotation of a DC electric motor be changed?

Interchange the wires which connect the motor to the external power source Signup and view all the answers

Which statement regarding an aircraft instrument vacuum system is true?

Dry-type vacuum pumps with carbon vanes are very susceptible to damage from solid airborne particles Signup and view all the answers

What marking color is used to indicate if a cover glass has slipped?

Red Signup and view all the answers

An aircraft magnetic compass is swung to update the compass correction card when an annual inspection is accomplished.

True Signup and view all the answers

What does a reciprocating engine manifold pressure gauge indicate when the engine is not operating?

Zero pressure Signup and view all the answers

When an aircraft altimeter is set at 29.92" Hg on the ground, the altimeter will read

Pressure altitude Signup and view all the answers

What is the purpose of the vertical fin?

Directional stability Signup and view all the answers

When using a universal propeller protractor to measure aileron travel, the measurement should be taken with the aileron in which position?

Neutral position Signup and view all the answers

What could be used to determine the primary flight control surface deflection for an imported aircraft reassembled after shipment?

Import manual for the aircraft Signup and view all the answers

If all instructions issued by the swaging tool manufacturer are followed, the resultant swaged terminal strength should be what?

The full rated strength of the cable Signup and view all the answers

What should fairleads never do to a cable's alignment?

Deflect alignment by more than 12° Signup and view all the answers

What is the purpose of spring tabs or servo tabs?

Assist the pilot in moving the control surfaces Signup and view all the answers

Which statement regarding the 100-hour inspection of an airplane equipped with a push-pull tube-type control system is true?

The threaded rod ends should not be adjusted in length for rigging purposes because the rod ends have been properly positioned and staked during manufacture. Signup and view all the answers

Movement about the longitudinal axis (roll) in a helicopter is affected by movement of the:

Cyclic pitch control Signup and view all the answers

What is the angle of incidence?

The acute angle formed by the chord line of a wing and the relative wind. Signup and view all the answers

Which safety device is acceptable for a castle nut when installed on secondary structures?

Cotter pin Signup and view all the answers

How are changes in direction of a control cable accomplished?

Fairleads Signup and view all the answers

What is buffeting?

The intermittent application of forces to a part of an airplane. Signup and view all the answers

Where does the breakage of control cable wires occur most frequently?

Where cables pass over pulleys and through fairleads Signup and view all the answers

Which type of aircraft control system increases the wing area and changes the wing camber?

Fowler flaps Signup and view all the answers

Study Notes

Assembly and Rigging

The purpose of a vertical fin is to provide directional stability, longitudinal stability, and lateral stability.
In a hovering helicopter equipped with a tail rotor, directional control is maintained by varying the pitch of the tail rotor blades.
The angle of incidence is the acute angle formed by the wing chord and the longitudinal axis of the aircraft.
The correct dihedral angle can be determined by measuring the angular setting of each wing at the rear spar with a bubble protractor.

Control Cables and Pulleys

Excessive wear on both sides of a control cable pulley groove is evidence of pulley misalignment.
Fairleads should never deflect the alignment of a cable more than 8°.
The purpose of a tension regulator in the flight control cable system is to retain a set tension.

Rotor Blade Movement

Movement about the longitudinal axis (roll) in a helicopter is affected by movement of the cyclic pitch control.
Movement about the lateral axis (pitch) in a helicopter is affected by movement of the collective pitch control.
In a hovering helicopter, directional control is maintained by varying the pitch of the tail rotor blades.

Aircraft Stability

An airplane with good longitudinal stability should have a minimum tendency to pitch or yaw.
Wing dihedral contributes most to stability of the airplane about its lateral axis.
An airplane that has a tendency to gradually increase a pitching moment that has been set into motion has poor longitudinal stability.

Control Surface Movement

During inspection of the flight control system of an airplane equipped with differential-type aileron control, side-to-side movement of the control stick will cause each aileron to have a greater up travel than down travel.
Movement of the cockpit control toward the nose-down position during a ground operational check of the elevator trim tab system will cause the trailing edge of the trim tab to move downward.

Safety Devices

A cotter pin is an acceptable safety device for a castle nut when installed on secondary structures.
The primary purpose of stall strips is to stall the inboard portion of the wings first.

Aircraft Inspections

The universal propeller protractor can be used to measure propeller track, aspect ratio of a wing, and degrees of flap travel.
A non-destructive checking method used to ensure that the correct amount of swaging has taken place when installing swaged-type terminals on aircraft control cable is to use a terminal gauge to check the diameter of the swaged portion of the terminal.

Helicopter Operations

In a single-rotor helicopter in forward horizontal flight, the angle of attack of the advancing blade is more than the retreating blade.
Changing direction of a control cable is accomplished using pulleys, bell cranks, and fairleads.

Aircraft Performance

When the lift of an airfoil increases, the drag will also increase.
If the right wing of a monoplane is improperly rigged to a greater angle of incidence than designated in the manufacturer’s specifications, it will cause the airplane to be off-balance both laterally and directionally.### Aircraft Systems
Breakage of cables can occur where they are heavy, corrected by adjusting the angle of incidence of wings or dihedral angle. (Q54)
The vertical fin of a single-engine, propeller-driven airplane should be parallel to the longitudinal axis but not the vertical axis when rigged properly. (Q54)

Control Cables

Aircraft control cables are terminated with swaged terminals, which must be corrosion treated and pull tested to show compliance with manufacturer's requirements. (Q65)
When inspecting a control cable turnbuckle, ensure no more than four threads are exposed on either side, and terminal end threads are visible through the safety hole in the barrel. (Q66)

Flight Dynamics

Elevators are used to provide rotation about the longitudinal axis. (Q67)
Differential control is associated with ailerons. (Q69)
Proper wing twist can be checked using a plum bob, string, and straightedge. (Q74)

Electrical Systems

Electric cables must be protected from chafing when passing through holes in bulkheads, formers, ribs, firewalls, etc. (Q2)
Grounding is electrically connecting a conductive object to the primary structure to prevent current return paths and radio frequency potentials. (Q13)
A battery-generator system provides direct current; for installations requiring alternating current, a transformer or inverter is necessary. (Q15)
When installing an anti-collision light, connect it to the aircraft position light switch, and use shielded electrical cable to assure fail-safe operation. (Q15)

Generators and Motors

A series-wound dc motor has high starting torque but is not suitable for constant speed use. (Q3)
A shorted transformer winding can be detected by measuring input voltage with an ohmmeter. (Q4)
A reverse current cutout relay contact point failure can cause current to flow in the opposite direction through the generator armature and shunt field. (Q5)
A generator brush arcing can be caused by carbon dust particles, low spring tension, or seating brushes with No. 000 sandpaper. (Q9)

Wiring and Switches

Aircraft fuse capacity is rated in amperes. (Q23)
When installing aircraft wiring, support the bundle to structure and/or fluid lines to prevent chafing damage, and provide adequate slack to compensate for temperature changes. (Q24)
A rectifier is used to change alternating current to direct current. (Q26)
A growler test is used to detect an out-of-round commutator, broken field lead, or shorted armature. (Q27)

Voltage Regulation

The inductor-type inverter output voltage is controlled by the dc stator field current. (Q29)
A compound dc generator is regulated by varying the current flowing through the shunt field coils. (Q33)
An inverter is used to regulate the voltage output of a compound dc generator. (Q32)

Diodes and Circuits

When checking a diode for an open circuit or short circuit, disconnect it from the circuit and use a milliamp ammeter. (Q38)
A circuit breaker in an instrument lighting system protects the wiring from too much current. (Q39)### Electrical Systems
The reverse current cutout relay controls the generator output.
When using the voltage drop method to check circuit point clearance, the input voltage must be maintained at a constant value.
When dc generators are operated in parallel, their controls include an equalizer circuit to assure that all generators share the load equally.

Generators

A series-wound dc electric motor will normally require more current at high RPM than at low RPM.
The voltage output of an alternator may be regulated by controlling the speed of the alternator, voltage output of the dc exciter, or resistance in the rotor windings.
A shunt-wound dc generator is connected with one field shunted across the other or both fields shunted across the armature.

Electrical Circuits

A current limiter is essentially a slow-blow fuse and is designed to be used in 400 cycle AC circuits or heavy power circuits.
When adding a rheostat to a light circuit to control the light intensity, it should be connected in series with the light.
A circuit breaker is installed in an aircraft electrical system primarily to protect the circuit and should be located as close to the source as possible.

Electrical Wiring

Aluminum wire must be stripped very carefully because stripping nicks can cause short circuits.
The acceptable method of attaching a terminal to a wire for general electrical use in aircraft is by crimping.
When considering an alteration, the criteria upon which the selection of electric cable size should be based are current-carrying capacity and allowable voltage drop.

Electrical Components

A voltage regulator controls generator voltage by changing the resistance in the generator output circuit.
A capacitor will largely eliminate radio interference and provide a steady direct current if connected to the generator in parallel.
The primary considerations when selecting electric cable size are current-carrying capacity and allowable voltage drop.

Electrical Measurements

To test generator or motor armature windings for opens, use a growler and connect a 110V test light on adjacent segments; the light should light.
A megohmmeter is used for measuring very high values of resistance.
An ammeter in a battery charging system is for the purpose of indicating the rate of current used to charge the battery.

Electrical Safety

If anyone generator in a 24-volt dc system shows low voltage, the most likely cause is a shorted or grounded wiring.
Overvoltage control automatically protects the generator system when excessive voltage is present by opening the shunt field circuit.
Electrical junction boxes located in a fire zone are usually constructed of stainless steel.

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Description

This quiz covers the basics of aircraft assembly and rigging, including the purpose of vertical fins, directional control in helicopters, and measuring dihedral angles.