Weight And Balance

Question 1

What is the datum and its purpose when making weight and balance computations?

Answer 1

It is the imaginary vertical plane from which all horizontal measurements are taken from

Question 2

What items concerning weight and balance could be found in the TCDS?

Answer 2

C. G. limits, datum, max weight, leveling means, seats and locations, baggage capacity and arm, fuel capacity and location, engine horsepower, unusable fuel and location, oil weight and location.

Question 3

What is the purpose of weight and balance control?

Answer 3

For safety.

Question 4

When computing weight and balance, what is the ‘moment’ and how is it obtained?

Answer 4

Moment is a force which tends to rotate the aircraft about one of its axis. Weight times arm

Question 5

How would a negative moment be obtained forward of the datum?

Answer 5

By adding weight.

Question 6

What is the ‘arm’ of an item and how is it obtained?

Answer 6

The arm is the distance (in inches) an item is located from the datum. It is obtained either by actual measurement or from the aircraft weight and balance records.

Question 7

What is ‘tare weight’, and how is it handled when making weight and balance calculations?

Answer 7

‘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 total weight.

Question 8

What is meant by ‘minimum fuel’ and how is it calculated for weight and balance?

Answer 8

The amount of fuel needed for an extreme condition check, to see if the center of gravity will be out of limits in that situation. For a reciprocating engine airplane, the calculation is: maximum except takeoff horsepower divided by two (METO - 2).

Question 9

What is meant by ‘residual’ fuel?

Answer 9

It is the fuel remaining in the tanks, sumps, lines, and engine after draining.

Question 10

What is meant by the center of gravity range? CG range

Answer 10

It is the distance in inches from the most forward acceptable center of gravity to the most rearward acceptable center of gravity.

Question 11

What is an aircraft loading graph?

Answer 11

A method (way) for determining load distribution so that the aircraft remains within its operating C.G. range.

Question 12

How would you determine the empty weight and empty weight C.G. of an aircraft if all weight and balance records are missing?

Answer 12

Re-weigh the aircraft and calculate new weight and balance records.

Question 13

What is the difference between fixed wing and rotor wing (helicopter) aircraft C. G. ranges?

Answer 13

Most helicopters have a more restricted C.G. range.

Question 14

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?

Answer 14

All operations equipment, whether it is required, optional, or special equipment must be included in the aircraft’s empty weight.

Question 15

Why do some manufactures specify an empty C.G. even though the aircraft is not operated at this empty weight?

Answer 15

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.

Question 16

Why must the aircraft category be considered when computing weight and balance?

Answer 16

Some aircraft are certified in both normal and utility categories. This means a different maximum allowable gross weight depending on which category the aircraft will be operated in for that day. (Two different useful load calculations.)

Question 17

Where is the center of gravity located in relation to the aerodynamic center of lift for most airplanes?

Answer 17

In front of the center of lift.

Question 18

What are two commonly ways used to show C.G. and/or C.G. range in different aircraft?

Answer 18

Inches from the datum, or percent of mean aerodynamic chord (%MAC).

Question 19

What should be done in regards to aircraft fuel when performing a weight and balance when draining is not an option?

Answer 19

When weighing an aircraft with full fuel tanks, the exact weight per gallon should be verified with a hydrometer. Then, the weight of the usable fuel) must be mathematically subtracted in the weight and balance calculations.

Question 20

What should be done concerning fuel when weighting an aircraft for weight and balance purposes?

Answer 20

With the aircraft in a level altitude, drain the fuel system until empty.

Question 21

What is ballast? And why is it used in aircraft?

Answer 21

Ballast is any weight add or removed to obtain a desired C.G.

Question 22

What are the placard requirements for ballast?

Answer 22

The ballast location must have a placard stating any limitations on contents, including weight, that are necessary under the loading requirements.

Question 23

What is recommended for marking of permanent ballast?

Answer 23

In red paint, mark with ‘permanent ballast, do not remove.’

Question 24

Name one common method of leveling an aircraft during weight and balance?

Answer 24

You may use a built in leveling scale and a plumb bob.

Question 25

Describe a plumb bob and its use.

Answer 25

It is a heavy object in the shape of a cone that is used to determine (locate) a spot directly below the point the tool is hanging from.

Question 26

How can you determine the effect of a new item of equipment on the aircraft weight and balance without weighing the aircraft?

Answer 26

The effect can be determined by basic computations if the weight and balance records are up to date

Question 27

how is the moment of an item of equipment obtained when computing aircraft weight and balance?

Answer 27

Weight times arm. (the moment of an item is obtained by multiplying the weight of the item by its horizontal distance from the datum).

Question 28

Why is accurate up-to-date empty weight center of gravity data so important?

Answer 28

All other weight and balance calculations are based on EWCG.

Question 29

How is a positive moment obtained aft of the datum?

Answer 29

By adding weight.

Question 30

How is a negative moment obtained aft of the datum?

Answer 30

By removing weight.

Question 31

What is meant by the term residual oil?

Answer 31

The oil remaining in the tank, lines, and engine after draining.

Question 32

Before a helicopter is weighed, it must be leveled in what direction?

Answer 32

Longitudinally and laterally.

Question 33

Explain the performance of a rearward adverse loaded CG check.

Answer 33

During an aft adverse-loaded CG check, all useful load items behind the aft CG limit are loaded and all useful load items in front the aft CG limit are left empty. (even though the pilot’s seat will be in front of the aft CG limit, pilot’s seat cannot be left empty). If the fuel tank is located forward of the aft CG limit, minimum fuel will be shown. Calculate CG to determine whether it falls within limits.

Question 34

Explain the performance of a forward adverse loaded CG check.

Answer 34

During a forward adverse-loaded CG check, all useful load items in front of the forward CG limit are loaded and all useful load items in behind the forward CG limit are left empty. Any seat or baggage compartment located behind the forward CG limit is left empty. If the fuel tank is located behind of the forward CG limit, minimum fuel will be shown in the tank. Calculate CG to determine whether it falls within limits.

Question 35

What does the term mean aerodynamic chord (MAC) refer to?

Answer 35

The MAC is the average chord or distance from the leading edge to the trailing edge of an airfoil, usually a wing, as measured in cross section

Question 36

Is there a federal regulation that requires the regular reweighing of private aircraft?

Answer 36

No.

Question 37

Where must a record of the most recent empty weight and center of gravity be kept?

Answer 37

It should be maintained in the airplane flight manual or weight and balance records. (In accordance
with FAR 23.1583)