Generals & Airframe
What is "tare weight", and how is it handled when making weight and balance calculations?
"Tare" is the weight of extra equipment used for weighing the aircraft such as chocks, blocks, jacks, and chains. Tare weight must be subtracted from the scale readings in order to obtain the Empty Weight of the aircraft.
Describe a no-trip circuit breaker (trip free).
(It pops when circuit gets hot and can't be reset until it has cooled off.)
What does an electrical circuit consist of?
1. A source (battery). 2. Resistance or load (Light bulb). 3. Conductors (Wires).
What percentage of flattening is allowed when bending metal tubing?
25% Max
What represents capacitance in an AC circuit?
A capacitor (same as a condenser).
What is the basic component that only allows current to flow in one direction?
A diode (acts like a check-valve)
What type of lines are used on aircraft drawings to indicate hidden views, center lines, and alternate position lines?
A hidden view line is a medium width line made up of short dashes. It represents and edge that cannot be seen when looking at the part from a specific position - - - - - - Center lines are thin lines composed of alternating long and short dashes, and are used to indicate the center of an object or center of a void — - — - — - — - Alternate position lines are medium width lines composed of one long and two short evenly spaced dashes. They are used to show the alternate position of apart or the relative position of a missing part — - - — - - — - - — - -
What instrument is used to determine the specific gravity of electrolyte in a lead acid battery?
A hydrometer.
What are two things that happen when current flows through a conductor?
A magnetic field is generated, and the conductor heats up,
What is an aircraft loading graph?
A method for determining load distribution so that the aircraft remains within its operating C.G. range.
What type of drawing is most helpful in troubleshooting a system?
A schematic.
What is an orthographic projection?
A way of illustrating an object in a drawing
How are standard AN type and AC type fluid line fittings identified?
AN fluid line fittings are colored either blue or black while AC type fittings are usually gray or yellow.
When using a hydrometer to check the charge of a lead-acid battery, at what temperatures must a correction factor be applied to the reading?
Adjustments must be made if temperature of the electrolyte is above 90°F or below 70°F.
When weighting an aircraft to determine the empty weight C.G., what must you do with regard to the fixed equipment which is normally carried in the aircraft?
All operations equipment, whether it is required, optional, or special equipment, must be included in the aircraft's empty weight.
What are the units that battery capacity are measured in?
Ampere-hours.
What material should be selected for high-pressure rigid fluid lines?
Annealed or 1/4-hard corrosion-resistant steel.
What is ballast?
Ballast can be lead bars, metal plates, shot bags, sand bags, or other items of weight which are placed in the aircraft to attain a desired C.G. Iocation.
What are some synthetic materials commonly used to manufacture flexible hoses?
Buna-N, Neoprene, Butyl, Ethylene propylene diene rubber, and Teflon.
If the forward C.G. Limit of an aircraft is exceeded after installing several items in the engine compartment, how could the limit be returned to limits without removing or changing any of the newly installed equipment?
By adding a ballast weight in the rear of the aircraft.
How would a negative moment be obtained forward of the datum?
By adding weight.
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 principle view.
How can a change to an aircraft drawing be identified?
By its revision letter (A, B, C, etc...).
How may the value of a small, fixed resistor be determined?
By the color bands on the resistor.
How is flexible hose sized?
By the inside diameter in sixteenths of an inch increments.
What items concerning weight and balance could be found in the TCDS?
C.G. limits, datum, max weight, leveling means, seat locations, baggage capacity and location,
Define "clearance" as used in aircraft drawings.
Clearance is the dimension given for the space between parts.
How are dimension lines shown on aircraft drawings?
Dimension lines are solid, and usually broken at midpoint for insertion of measurement indications | ——————— 27" —————— |
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. Thev are used to indicate the size of an object.
What is the concept that describes the relationship between electricity and magnetism?
Electromagnetism.
How often should flexible hoses be clamped in place?
Every 24 inches.
What is the unit of measure for capacitance?
Farad.
How much slack must be left in a flexible hose during installation?
Five to eight percent of the total hose length
What is the purpose of weight and balance control?
For safety and efficiency in flight.
What is the standard unit of measure for frequency?
Hertz.
Where is the center of gravity located in relation to the aerodynamic center of lift for most airplanes?
In front of the center of lift.
What is recommended for marking of permanent ballast?
In red paint, mark with "permanent ballast, do not remove."
Where is the title block usually found on an aircraft drawing?
In the lower right corner.
What are two common ways of representing the C.G. of an aircraft?
Inches from the datum, or percent of mean aerodynamic chord (%MAC).
What causes opposition to the flow of current in an AC circuit?
Inductive, and capacitance reactance.
A 24 volt lead-acid battery has how many cells?
It has 12 cells. Each cell is rated at approx. 2 volts.
What is a kilowatt?
It is 1,000 watts.
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.
Describe a plumb bob and its use.
It is a heavy object in the shape of a cone that is used to determine a spot directly below the point the tool is hanging from.
What is the "bill of materials" associated with aircraft blueprint?
It is a list of materials and parts necessary for fabrication or assembly of a component or system.
What is the datum and its purpose when making weight and balance computations?
It is an imaginary vertical line or plane from which all measurements are taken both forward and aft to determine the relative location of items in the aircraft.
What is a fuselage station number?
It is the distance from the datum measured in inches along the longitudinal axis.
What is meant by the center of gravity range?
It is the distance in inches from the most forward acceptable center of gravity to the most rearward acceptable center of gravity.
What is meant by "residual" fuel?
It is the fuel remaining in the tanks, sumps, lines, and engine after fuel exhaustion.
What is electromagnetic induction?
It is the transfer of electrical energy by means of a magnetic field (lines of flux).
What should be the specific gravity of the electrolyte in a fully charged lead acid battery?
It should be between 1.275 and 1.300.
How should an aircraft be leveled for weighing during a weight and balance?
It should be leveled per the requirements of the Aircraft Specifications, or Type Certificate Data Sheet.
Where must a record of the most recent empty weight and center of gravity be kept?
It should be maintained in the airplane flight manual or weight and balance records. (In accordance with FAR 23.1583)
How should aircraft fuel be drained for weight and balance?
Level the aircraft per the TCDS and then drain the fuel system until empty.
What is the common name for the lines of force that make up a field surrounding a magnet?
Magnetic flux lines.
What are aircraft plumbing lines usually made of?
Metal tubing or flexible hose and fittings.
When computing weight and balance, what is the "moment" and how is it obtained?
Moment is a force which tends to rotate the aircraft about one of its axis. It is obtained by multiplying the weight of an item (pounds) by the distance of the item from the datum (inches). It is expressed in "inch-pounds." (W x A = M)
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.
Is there a federal regulation that requires the regular reweighing of private aircraft?
No.
What is the most important law applicable to the study of electricity?
Ohm's Law (E = Ix R).
What is the unit of measurement for impedance?
Ohms.
How would you determine the empty weight and empty weight C.G. of an aircraft if all weight and balance records are missing?
Re-weigh the aircraft and calculate new weight and balance records.
What precautions should be taken when routing fluid lines adjacent to electrical wiring?
Route the fluid lines below the electrical wiring and maintain a clearance of at least six inches whenever possible.
How is metal tubing sized?
Ry outside diameter and wall thickness.
Name considerations when installing flexible hose assemblies.
Slack, flexing, twisting, bending, clearance, and clamps.
Why must the aircraft category be considered when computing weight and balance?
Some aircraft are certified in both normal and utility categories.
What type of material should fittings be made of when used with stainless steel tubing?
Stainless steel.
Why are symbols used when drawing aircraft blueprints?
Symbols are a type of shorthand used in drawings.
What is the difference between fixed wing and rotor wing (helicopter) aircraft C.G. ranges?
The C.G. location in a helicopter is much more critical than fixed-wing aircraft
What is meant by "minimum fuel" and how is it calculated for weight and balance?
The amount of fuel needed for an extreme condition check.
What is the "arm" of an item and how is it obtained?
The arm is the distance (in inches) an item is located either forward or aft of the datum. It is obtained either by actual measurement or from the aircraft weight and balance records.
What are the placard requirements for ballast?
The ballast location must have a placard stating any limitations on contents, including weight, that are necessary under the loading requirements.
What is an example of an inductor in a magneto?
The coil.
Define "tolerance" as used in aircraft drawings.
The difference between the plus and minus allowable dimension of a part. (+/- of .005 = .010)
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.
How can you determine if a part will affect the CG without weighing the aircraft?
The effect can be determined by basic computations
Why can a hydrometer NOT be used to determine the charge of a nickel-cadmium battery?
The specific gravity of the electrolyte in a nickel-cadmium battery does not change appreciably during charge or discharge of the battery.
What happens to the specific gravity of the electrolyte in a lead acid battery when the temperature changes?
The specific gravity readings on a hydrometer will vary with temperature variations.
What is the purpose of the identification stripe running along the length of a flexible hose?
The stripe is called a lay line and indicates if the hose has twisted during installation. There is no allowable twist.
What is impedance?
The total opposition for AC to flow caused by the combined effect of resistance, inductive reactance, and capacitive reactance in an AC circuit.
What is the unit of measurement of power in a DC circuit?
The watt. Amperes times volts equals watts (P = Ix E). 746 watts equals one horsepower.
What are the four factors that affect the resistance of an electrical conductor?
The wire gauge, length, temperature, and material.
In a DC circuit, what occurs when voltage is increased while resistance remains constant?
There will be an increase in current.
What are four sources of electrical energy?
Thermal, light, pressure, and chemical.
What are the three types of DC electrical circuits?
They are Series circuits, Parallel circuits, and Complex circuits (series and parallel).
How are battery compartments protected against corrosion?
They are coated with special corrosion resistant paint such as bituminous paint.
What is the purpose of one view drawings?
They are used for objects of uniform thickness, such as gaskets, shims, and plates.
What is the purpose of using quick disconnect couplings in fluid systems?
They provide a means of quickly disconnecting a line without a loss of fluid or air entering the system.
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
How many views are required to determine the shape of an object?
Three views: Front, Top, and Right side.
What is the general purpose of a resistor?
To limit current.
What is the function of a capacitor?
To store electricity.
What pressure is used to proof-test a flexible hose assembly?
Typically 1.5 times the recommended operating pressure of the hose.
What are the elements of Ohm's Law?
Voltage (E), Current (I), and Resistance (R)
What is the result of an imbalanced cell in a nickel-cadmium battery?
When a cell has a low internal resistance, the current will increase across the cell, causing it to heat up.
Why do some manufactures specify an empty C.G. even though the aircraft is not operated at this empty weight?
When the empty weight C.G. falls within the empty weight C.G. range, it is unnecessary to perform a weight and balance check if standard loading and seating arrangements are used.
What is inductance?
When voltage is induced by magnetic flux lines in a coil in an AC circuit. The induced voltage is opposite in direction to the applied voltage, and opposes any change in the alternating current.
What should be done in regards to aircraft fuel when performing a weight and balance when draining is not an option?
When weighing an aircraft with full fuel tanks, the exact weight per gallon should be verified with a hydrometer.
Name one common method of leveling an aircraft during weight and balance?
built in leveling scale and a plumb bob.
What should be the correct electrolyte level in a properly serviced battery?
electrolyte It should be approximately 3/8 inches above the plates.
