A&P - General Oral Exam (Jeppesen)

How do you convert a fraction into a percent?

Convert into a decimal and then multiply by 100 and adding the % sign.

What are two different ways that a ratio may be expressed?

1. As a fraction
2. By placing a colon (:) between the two numbers
3. Use the word "to" between the two numbers.

What is meant by the root of the number?

A smaller number that when multiplied by itself two or more times results in the specified number.

What formula is used to find the area of a rectangle and a triangle?

Rectangle = L x W
Triangle = 1/2 (B x H)

Define Pi.

Pi is a constant that defines the relationship between the circumference and the diameter of a circle. Approximately equal to 3.1416

Work is the product of what two factors?

Force and distance moved.

What are the parts of a lever?

A rigid bar and a pivot point called the fulcrum.

What is a British Thermal Unit?

The amount of heat energy required to change the temp of 1 pound of water 1 degree Fahrenheit.

What formula expressed the relationship between force, pressure and area?

Force equals area times pressure.

What is the approximate speed of sound at sea level on a standard day?

661 knots or 340 meters per second.

What are the factors that determine density altitude?

Temperature and atmospheric pressure.

What are the four principle forces acting on an airplane in flight?

Lift, drag, thrust, and gravity.

What are the factors that cause the airplane wing to stall?

Stall is caused when the angle of attack exceeds a critical value and the airflow separates from the upper surface and becomes turbulent.

What is the function of a wing mounted vortex generator?

Vortex generators delay or keep the airflow from separating from the upper surface of a wing during high speed flight.

How does blade flapping help to compensate for dissymmetry of lift in helicopter main rotor systems?

Flapping increases the angle of attack and lift on the retreating blade and decreases the angle of attack and lift on the advancing blade.

How does the airflow through the main rotor of a helicopter change during the transition from normal flight to autorotation?

During normal flight the air moves downward and during autorotation the air moves upward.

What is friction?

The opposition to relative motion between two objects in contact with each other.

One kilowatt is equal to how many watts?

1,000 watts

What law describes the most fundamental or basic relationship in an electrical circuit?

Ohm's law

What are the three elements of Ohm's law?

Voltage, current, and resistance.

How would you write the Ohms law as an equation?

E=I x R, R = E/I, or I= E/R

Describe the result of adding a large positive number and a smaller negative number.

The result is a smaller positive number.

How do you convert a fraction into a decimal?

Divide the numerator by the denominator.

What is the key step that must be performed in order to add or subtract unlike fractions?

Find the lowest common denominator.

How do you divide one fraction by another?

Invert the divisor and multiply.

How can you convert a decimal into a percent?

Multiply by 100 and add the % sign.

How do you change a decimal into the nearest equivalent fraction?

Multiply by the desired denominator to get the numerator.

What is a proportion?

A statement of equality between two or more ratios.

How do you find the square of a number?

Multiply the number by itself.

What is the common method of making computations involving very large or very small numbers more manageable?

Convert into scientific notation using powers of 10.

How is 100,000 expressed as a power of 10?

10 to the 5th power.

Describe a trapezoid.

A trapezoid is a closed, four sided figure with two parallel sides.

What is the formula for computing the area of a circle?

Pi (r x r). Pi R squared!

Define matter.

Anything that occupies space and has mass.

Matter may exist in what three states?

Solid, liquid, and gas.

Define kinetic energy?

Energy of motion.

A wheelbarrow is a example of what class of lever?

A second-class lever.

Are all three states of matter affected by thermal expansion and if so, which state is affected most?

All three states are affected, with gas being affected the most.

Name the three methods of heat transfer?

Conduction, convection and radiation.

What term defines the temperature at which all molecular motion ceases?

Absolute zero.

Can liquids be compressed?

No, liquids are generally considered incompressible.

What are the customary units used to express hydraulic or pneumatic pressure in the U.S.?

Pounds per square inch

Describe how pressure is transmitted when a force is applied to a confined liquid.

Pressure is transmitted equally in all directions.

What is the atmospheric pressure at sea level on a standard day?

29.92 inches of Mercury or 1013.2 millibars.

On a standard day at sea level, what is the value for temperature?

59 deg. F or 15 deg. C

What is the term to describe the ratio between the amount of moisture actually present in the atmosphere as compared to the amount the air could hold if it were completely saturated?

Relative humidity.

What is the term that describes the angle between the relative wind and the chord line of airfoil?

The Angle of Attack (AOA).

What are the principle effects that result from lowering the flaps while in flight?

Lift increases, drag increases, and stall speed decreases.

If the resistance in a DC circuit remains the same but the voltage doubles, what happens to the amount of current flowing in the circuit?

It also doubles.

In DC circuits, what unit measures power?

Watts

What three elements are required to form an electrical circuit?

A source of electrical energy, a load or resistance to use the electricity, and wires or conductors to connect the source to the load.

DC circuits can take one of three forms or types, What are they?

Series, parallel, and complex (series-parallel).

A 24-volt lead-acid battery has how many cells?

12

A fully charged lead-acid battery has a specific gravity that varies between what two values?

1.275 and 1.3

You must apply a correction to the specific gravity reading of the elctrolyte of a lead-acid battery when the temp is outside of what two values?

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

What is the reason for having separate facilities for storing and servicing nickel-cadmium and lead-acid batteries?

The electrolyte in the two types of batteries is chemically opposite and the fumes from one type can contaminate the electrolyte of the other type.

The state of charge of a nickel-cadmium battery cannot be determined by measuring the specific gravity of the electrolyte for what reason?

There is no significant change in the specific gravity of the electrolyte as the battery is charged or discharged.

What is the principal advantage of AC current over DC current?

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

Resistance, inductive reactance, and capacitive reactance.

Define inductance.

An induced voltage which is opposite in direction to the applied voltage.

What component creates capacitance in AC circuits?

A capacitor.

How does a capacitor store electricity?

The energy is stored in the form of an electrostatic charge that exists between two conductors separated by an insulator.

What property of an AC circuit is defined by the term impedance?

The total opposition to the current flow.

What are the two reasons that might cause a nickel-cadmium battery to fail to deliver its rated capacity?

Faulty cells or cell imbalance.

What electrical values are measured by a typical mulimeter?

Voltage, current, and resistance.

How many views are required to represent the important details of most aircraft parts?

One, two, or three views are usually enough.

What kind of parts can be represented by one-view drawings?

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

What is the name for a part of a drawing used to bring out important details and how is it drawn?

A detailed view, which is usually drawn to a larger scale than the main drawing.

What is the purpose of schematic diagrams?

Primarily used for troubleshooting systems.

Describe an orthographic projection.

A way of drawing an object using different views at right angles to each other, such as top, bottom, front, and side view.

Why do manufacturers use symbols on aircraft drawings?

Symbols are a form of shorthand and are used to convey the characteristics of a component with a minimum of drawing.

Describe the appearance of lines used to show hidden views, alternate positions, and the middle of symmetrical objects, and give their name.

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 can you determine if a drawing has been changed?

A record of the changes is listed either in the revision block or in ruled columns which may be in the corner of the drawing or next to the title block.

How are dimensions shown on aircraft drawings, and what is their purpose?

"Dimension lines" are usually solid and generally broken in the midpoint for insertion of the measurement. They provide a means to accurately represent the size of an object.

What is the difference between an "allowance" and a "tolerance"?

An allowance is the difference between the nominal dimension and the maximum and minimum permissible sizes. The tolerance is the difference between the extreme permissible dimensions, which may be found by adding the plus and minus allowances.

What is meant by "clearance" when used in aircraft drawings?

An allowable dimension between two parts.

What kinds of information about an aircraft drawing can be found in the title block?

The part or assembly name, drawing size, scale, date, company name, and name or initials of the people responsible for creating and approving the drawing.

What information is contained in a "bill of materials"?

A list of the materials and parts needed to fabricate or assemble the component or system shown in the drawing.

If an aircraft is loaded so that the aft C.G. limit is exceeded, what undesirable flight characteristic is likely to result?

The aircraft will be tail-heavy and may be unable to recover from a stall or spin.

If all the records for an aircraft are missing, how would you determine the empty weight and empty weight C.G.?

The aircraft would have to be weighed, and new weight and balance records would have to be prepared.

Define" tare weight" and describe how it is handled when weighing an aircraft.

Tare weight of anything on the scales that is not part of the aircraft. If must be subtracted from the scale weight reading too determine the net weight of the airplane.

If a piece of equipment such as a radio is added to an aircraft, how can you determine the effect on weight andbalance without re-weighing the airccraft?

If the weight and balance records are up to date, a new weight and C.G. location can be determined by computation.

Why is control of the weight and ballance of an aircraft important?

To provide maximum safety.

What is the datum of an aircraft and what is its function?

The datum is an imaginary vertical plane at right angles to the longitudinal axis of the airplane. It is the reference point from which all horizontal measurements are taken.

How do you determine the moment of an item of equipment?

The weight of the item is multiplied by its arm, which is the distance between the item and the datum.

What are two ways of determining the arm of an item of equipment?

Measure the distance between the item and the datum, or use data supplied by the manufacturer.

What should be done to obtain a positive (plus) moment aft of the datum?

Add weight.

What should be done to obtain a negative (minus) moment aft of the datum?

Remove weight.

What should be done to obtain a positive (plus) moment forward of the datum?

Remove weight

What should be done to obtain a negative (minus) moment forward of the datum?

Add weight

How does the category of an aircraft affect its loaded weight?

Aircraft certificated in more one category, such as normal and aerobatic, may have two different maximum gross weights and different useful loads.

As you prepare an aircraft for weighing, you determine that there is equipment aboard that is not permanently installed and recorded on the equipment list. What should you do with equipment?

All equipment not permanently installed in the aircraft or included on the equipment list should be removed from the aircraft.

Define the term "residual fuel"?

Any fuel that remains in the tanks, lines, and engines, after the system has been drained.

Define the term "residual oil"?

Any oil that remains in the tanks, lines, engines, after the system has been drained.

How should you account for fuel when weighing an aircraft to determine weight and balance?

Either drain the system until only unusable fuel remains, or fill the tanks full and subtract out the weight of the useable fuel.

Where are leveling instructions found, and describe one method of leveling an aircraft?

Leveling instructions are found in the Type Certificate Data Sheets. An aircraft may be leveled by using a spirit level at specified points, or an aircraft may be leveled by using a plumb bob from a designated point along with a leveling scale or protractor.

Define the term "Mean Aerodynamic Chord" or MAC.

Mean Aerodynamic Chord is the chord drawn through the center of the wing plan area.

Describe the two most common ways of showing the C.G. location and/or C.G. range.

In inches from the datum or in percent of MAC.

What is the purpose of an aircraft loading graph?

It is a method for determining how to distribute the load so as to keep the C.G. within allowable limits.

What is ballast, and why would you use it in an airplane?

Ballast is weight added to an airplane to bring its C.G. into the allowable or desired range.