Weight & Balance Flashcards
What is the datum and its purpose when making weight and balance computations?
It is an imaginary vertical line or plane used in weight and balance calculations from which measurements are taken both forward and aft to determine the relative location of items in the aircraft. The distance from the datum, in inches, to the weight center of an item is called the “arm.”
What is the purpose of weight and balance control?
Safety and efficiency in flight.
When computing weight and balance, what is the “moment” and how is it obtained?
A moment is a force, which tends to rotate the aircraft about its center of gravity. It is obtained by multiplying the weight of an item (pounds) by the distance of the item from the datum (inches). It is, therefore, expressed in “pound-inches.”
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 datum. It is obtained either by actual measurement or from the aircraft weight and balance records.
What is “tare” weight, and how is it handled when making weight and balance calculations?
“Tare” is the weight of the 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 actual weight of the aircraft.
What is meant by “minimum fuel” and how is it calculated for weight and balance purposes?
Minimum fuel is the amount of fuel that should be used in weight and balance computations when the aircraft is loaded for an extreme condition check. For a reciprocating engine airplane certificated under FAR Part 23, this is the fuel necessary to operate the engine(s) for one-half hour at maximum continuous power.
What is meant by “residual” fuel?
It is the fuel remaining in the tanks, lines, and engine after draining. Also called “undrainable” or “unusable,” it is part of the aircraft’s empty weight.
How would you determine the empty weight and empty weight CG of an aircraft which has a tricycle landing gear if all weight and balance records are missing?
Use three scales and record the weight under each wheel. Then, measure the distance in inches from the nosewheel to the main gear and multiply this figure by the combined weight of each main wheel. Into this number divide the total weight of the aircraft. The answer will be the number of inches the CG is located aft of the nosewheel. NOTE: This can be proved by using the figures in Problem 2. You should find a CG 46.75 inches aft of the nosewheel. The nosewheel is 8 inches forward of datum.
What is “ballast”?
Ballast is lead bars, metal plates, shot bags, sand bags, or other items of weight which are placed in an aircraft to attain a desired CG location.
What is the difference between fixed-wing aircraft and helicopter CG ranges?
The CG location in a helicopter is much more critical than in fixed-wing aircraft. The CG range in some helicopters is less than three inches.
When weighing an aircraft to determine the empty weight CG, what must you do with regard to the equipment which is normally carried in the aircraft?
All operating equipment whether it is required, optional, or special equipment must be included in the aircraft’s empty weight.
Why do some manufacturers specify an empty weight CG even though the aircraft is not operated at this empty weight?
When the empty weight CG falls within the empty weight CG range, it is unnecessary to perform a forward or aft weight and balance check if standard loading and seating arrangements are used?
. Why must the aircraft category be considered when computing weight and balance?
Some airplanes are certificated in both normal and utility categories. This means a different maximum allowable gross weight depending on which category the aircraft will be operated in.
What undesirable flight characteristic is most likely to result from exceeding the forward c.g. limit of an aircraft?
It may lead to insufficient stability with resulting difficulty in controlling the aircraft.
. The forward c.g. limit of an aircraft is exceeded by installation of several items of equipment in the engine compartment. How can this problem be corrected or compensated for without removing or changing any of the newly installed equipment?
Ballast is used in an aircraft to attain the desired c.g. balance.
