A&P - General Oral Exam

What is considered the basic building block of all matter?

The atom.

What is the most important law applicable to the study of electricity?

Ohm law.

What is Ohm's law expressed as an equation?

Volt = Current x Resistance

What are the elements of Ohm's law?

Voltage, current, and resistance.

What are four sources of electrical energy?

Thermal, light, pressure, and chemical.

What does a basic DC electrical circuit consist of?

A source, battery, resistance or load, a light bulb, and conductors, wires.

What represents capacitance in an AC circuit?

A capacitor.

What is the function of a capacitor?

To store electricity.

What is the unit of measure for capacitance?

Farad.

What is the standard unit of measure for frequency?

Hertz.

What is the basic component that only allows current to flow in one direction?

A diode.

What is inductance?

The ability to store electrical energy in electromagnetic fields. which induced voltage that is opposite in direction to the applied voltage.

What is one advantage of AC circuits over DC circuits in an aircraft?

Power can be transmitted over long distances more efficiently and with smaller wires because the voltage can be easily increased or decreased by a transformer.

What is the definition of a short circuit?

unintended low-resistance path that allows current to flow directly to ground or another conductor.

What is an example of an inductor in a magneto?

The coil.

What is impedance?

The total opposition to the current flow in electrical circuit.

What causes opposition to the flow of current in an AC circuit?

Resistance, inductive reactance, and capacitive reactance.

What is the unit of measurement for impedance?

Ohms.

What is the general purpose of a resistor?

To limit current.

How may the value of a small fixed resistor be determined?

By the color bands on the resistor.

What are two things that happen when current flows through a conductor?

A magnetic field is generated and the conductor heats up.

What is the common name for the lines of force that make up a field surrounding a magnet?

Magnetic flux lines.

What is magnetism?

is the force of attraction or repulsion between materials

What is the difference between permanent and temporary magnets?

Permanent magnets keep their magnetism for a long time after the magnetizing force is removed.

Temporary magnets lose their magnetism quickly when the magnetizing force is removed

What is the concept that describes the relationship between electricity and magnetism?

Electromagnetism.

What are the four factors that affect the resistance of an electrical conductor?

The wire gauge, length, temperature, and material.

What is the unit of measurement of power in a DC circuit?

Watt.

What is a kilowatt?

1,000 watts in a DC circuit.

What occurs when voltage is increased while resistance remains constant?

There will be an increase in current.

What are the three types of DC electrical circuits?

Series, parallel and complex or series and parallel.

A 24V lead acid battery has how many cells?

12 cells. And each cell is rated at approximately 2 volts.

What is the most frequent cause of damage to a solid state component and integrated circuits?

Electrostatic discharge from the human body due to careless handling.

What are the units that battery capacity is measured in?

ampere-hours

What should be the specific gravity of the electrolyte in a fully charged lead acid battery?

It should be between 1.275 and 1.3.

What instrument is used to determine the specific gravity of electrolyte in a lead acid battery?

A hydrometer.

Why can a hydrometer not be used to determine the charge of a nickel cadmium battery?

The electrolyte specific gravity does not change with the state of charge.

When using a hydrometer to check the change of a lead acid battery, at what temperature must a correction factor be applied to the reading?

if the temperature of electrolyte is less than 70 deg. F or more than 90 deg. F.

What is the effect of temperature on specific gravity of the electrolyte when checking a lead acid battery?

Whenever the temperature is less than 70 deg. F or more than 90 deg. F.

What is electromagnetic induction?

is when a magnetic field creates voltage in a conductor without direct contact.

How are battery compartments protected against corrosion?

They're coated with special corrosion resistant paint.

What should be the correct electrolyte level in a properly serviced battery?

should be about 3/8 inch above the plates, or up to the hole in the baffle plates if they are present.

What are paralleling generators and how is the load distributed?

This is when two or more generators are operated at the same time to supply power for a load that must be shared equally.

Describe a no trip circuit breaker.

no trip breaker cannot be held closed manually if too much current is flowing.

Can you store Ni-cad and lead acid batteries together?

No. The fumes from the lead acid battery can contaminate the electrolyte in the Ni-cad battery.

Why should nickel cadmium batteries and lead acid batteries not be serviced in the same area?

The electrolyte and the fumes from lead acid batteries can contaminate the electrolyte in the nickel cadmium battery.

What could cause a nickel cadmium battery to fail to deliver its rated capacity?

Cell imbalance or faulty cells.

What is the result of an imbalanced cell in a nickel cadmium battery?

The current increases across the cell, causing it to heat up

What happens to the specific gravity of the electrolyte in a lead acid battery when the temperature changes?

The specific gravity of a lead-acid battery changes with temperature: it reads higher when hot and lower when cold.

What is an LED?

is a light-emitting diode

What is SLA battery?

Sealed lead acid battery.

What is the basic unit of measure for inductance?

Henry.

What prevents reverse current flow in a DC alternator?

Reverse current cutout.

How many wires may be installed on a single terminal lug?

four

How do you identify wire types?

letters or markings on the insulation

Name some functions of a multimeter.

Measure voltage, current, and resistance.

How would a technician connect a multimeter in a circuit to read its current?

connects a multimeter in series with the circuit to measure current

Name two types of resistors.

Variable and fixed.

What is the difference between an or logic gate and an and logic gate?

An or logic gate needs one input or the other input to have an output. The and logic gate needs one input and the other input to have an output.

What are two materials that conductors are made of?

Aluminum and copper.

What component changes electrical energy of a given voltage into electrical energy at a different voltage level?

Transformer.

Describe a capacitor.

two conductive plates separated by an insulator

What is an inverter?

An inverter changes electricity from DC power to AC power.

What is the difference between the two theories? Conventional current flow theory and electron flow.

Conventional current flow is current moves from positive to negative, and electron flow is the actual movement from negative to positive.

What is Kirchoff's voltage law?

In a closed loop, all the voltages add up to zero.

What electrical law is most used in troubleshooting?

Ohms law.

What is the right hand motor rule?

Point index finger along the magnetic field and your middle finger along the current; your thumb shows the direction the wire moves.”

What flows around a conductor?

A magnetic field, electrical current and electrons.

What is the definition of power?

Power is how fast energy is used or changed in a system

When is a full section view used on an aircraft drawing?

When interior construction or hidden features of an object cannot be shown clearly by exterior views.

What type of lines are used on aircraft drawings to indicate hidden views, center lines, and alternate position lines?

Hidden views are shown with "hidden lines", which are short, evenly spaced dashes.

Alternate positions are shown with "phantom lines" made up of light, alternating long dashes and two short dashes.

"Center lines" consisting of alternating long and short dashes, show the middle of symmetrical objects.

How are dimension lines shown on aircraft drawings?

Dimension lines are solid and usually broken at midpoint for insertion of measurement indications.

What is a sketch for a repair?

It is a basic drawing that shows specific information and provides minimum detail needed to manufacture a part.

How may an aircraft drawing of a part be drawn to bring out pertinent details?

By drawing a detailed view at a larger scale than the principal view.

What type of drawing is most helpful in troubleshooting a system?

A schematic.

Define tolerance as used in aircraft drawings.

the difference between the plus and minus allowable dimensions of a part.

Define clearance as used in aircraft drawings.

Clearance is the dimension given for the space between parts.

What is a fuselage station number?

It is the distance from the datum measured in inches along the longitudinal axis.

What information is given in the title block of a blueprint?

The drawing number, the name of the part or assembly, the scale, the date, the name of the firm, the name of the draftsman, the checker, and the approving official.

Where's the title block usually found on an aircraft drawing?

In the lower right corner.

Why are dimensions used and how are they shown on the aircraft drawings?

Dimensions are solid narrow lines broken at midpoint for the insertion of measurements. They're used to accurately represent the size of an object

How can a change to an aircraft drawing be identified?

By its revision letter. The revision letters are usually listed in a table next to the title block or in the corner of the drawing.

What is the bill of materials associated with aircraft blueprints?

Is a list of materials and parts necessary for fabrication or assembly of a component or system.

Why are symbols used by manufacturers when drawing aircraft blueprints?

Symbols are a type of shorthand used in drawings. They express the characteristics of a component with a minimum amount of drawing or writing.

What is an orthographic projection?

A way of illustrating an object in a drawing by showing different views at right angles to each other such as front and side views.

How many views are required to determine the shape of an object?

1, 2, 3 views, front, right, and top.

What is the purpose of one view drawings?

Parts with uniform thickness such as shims, plates, and gaskets.

What are schematic diagrams generally used for?

They are mainly used for troubleshooting.

What property is essential for metals used in making wire and tubing?

The property of ductility.

What is a suitable non-destructive testing method for detecting surface cracks on aluminum castings and forgings?

Visual, dye penetrant, eddy current, ultrasonic testing and radiography.

List the steps in a die penetrint inspection.

The surface is cleaned, and then penetrant is applied to dwell for a specified time. The penetrant is then removed with an emulsifier or cleaner. Once removed, the part is dried and then developer is applied. The results are then inspected and interpreted.

Describe the procedure for performing a magnetic particle inspection.

Magnetize the part, then coat the surface with ferromagnetic particles. If a defect or discontinuity is present, the particles align with the discontinuity forming a visible pattern.

What are the two types of self-locking nuts?

All metal and fiber lock.

What is the general rule for using self-locking nuts?

Do not use self-locking nuts at joints which are subject to rotation.

What type of cable is used in primary control systems?

Extra flexible 7 by19 cable.

How can the correct grip length of a bolt be determined?

Is the length of the unthreaded portion. and it should match the thickness of the materials joining together.

The length of an A in standard bolts are measured in what fraction?

1/8 of an inch.

What does the triangle mean on the head of a steel bolt?

That it is a close tolerance bolt.

What numbers are used for close tolerance bolts?

A1 173–A1 186 for hex bolts, and NAS 80–NAS 86 for countersunk bolts.

What is the difference between a standard bolt and a close tolerance bolt?

A close tolerance bolt is machined to more precise dimensions and is used in high performance applications.

A solid rivet diameter is always measured in what fraction?

1/32 of an inch