Weight and Balance

Question 1

When should an aircraft be reweighed?

Answer 1

After an extensive repair or alteration that could change its weight or center of gravity.

Question 2

Why is it necessary to consider the category under which an aircraft is licensed when computing its weight and balance?

Answer 2

Different categories under which an aircraft can be licensed have different maximum gross weights and different center of gravity ranges.

Question 3

Where do you find the leveling means that are specified for a particular aircraft?

Answer 3

In the TCDS for the aircraft.

Question 4

What is meant by tare weight?

Answer 4

The weight of any chocks and other items that are used to hold the aircraft on the scales.

Question 5

What must be done with tare weight when an aircraft is weighed?

Answer 5

It must be subtracted from the scale readings to find the weight of the aircraft.

Question 6

Why are the distances of all the items installed in an aircraft measured from the datum when computing weight and balance?

Answer 6

This makes it possible to find the point about which the aircraft would balance (the center of gravity).

Question 7

Which has the more critical center of gravity range, an airplane or a helicopter?

Answer 7

A helicopter.

Question 8

What is included in the empty weight of an aircraft?

Answer 8

The weight of the airframe, engines, and all items of operating equipment that have fixed locations and are permanently installed in the aircraft. Empty weight includes option and special equipment, fixed ballast, full reservoirs of hydraulic fluid and engine lubricating oil, and unusable fuel.

Question 9

Where is the maximum allowable gross weight of an aircraft found?

Answer 9

In the TCDS for the aircraft.

Question 10

What equipment must be installed in an aircraft when it is weighed to find its empty weight center of gravity?

Answer 10

All the equipment list in the Aircraft Equipment List as “required equipment” or as equipment that is permanently installed.

Question 11

What is meant by permanent ballast for an aircraft?

Answer 11

Weight that is permanently installed in an aircraft to bring the empty weight center of gravity into allowable limits.

Question 12

Is there a Federal Regulation requiring that all private aircraft be reweighed periodically?

Answer 12

No.

Question 13

What must be done with temporary ballast when weighing an aircraft?

Answer 13

It must be removed from the aircraft.

Question 14

What must be done to find the empty weight of an aircraft if it has been weighed with fuel in its tanks?

Answer 14

The weight of the fuel and its moment must be subtracted from the weight and moment of the aircraft as it was weighed.

Question 15

What is meant by minimum fuel as is used in the computation of aircraft weight and balance?

Answer 15

No more fuel than the quantity necessary for one-half hour of operation at rated maximum continuous power. It is the maximum amount of fuel used in weight and balance computations when low fuel may adversely affect the most critical balance conditions.

Question 16

What is meant by the maximum zero fuel weight of an aircraft?

Answer 16

The maximum permissible weight of a loaded aircraft (passengers, crew, cargo, etc.) less its fuel.

Question 17

What is meant by undrainable fuel?

Answer 17

The fuel that is left in the tank, lines and components when the aircraft is placed in level flight position and the fuel drained at the main fuel strainer. This is also called residual fuel.

Question 18

Describe the way you find the empty weight and empty weight center of gravity of an airplane if there are no weight and balance records available.

Answer 18

The aircraft is weighed, and the empty weight center of gravity is computed. These values are recorded in a new weight and balance records started for the aircraft.

Question 19

What are two reasons weight and balance control are important in an aircraft?

Answer 19

For safety of flight and for most efficient operation of the aircraft.

Question 20

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

Answer 20

The CG is normally ahead of the center of lift.

Question 21

What is meant by the datum that is used for weight and balance computations?

Answer 21

It is a readily identified reference chosen by the aircraft manufacturer from which all longitudinal locations on the aircraft are referenced.

Question 22

What is meant by moment in the computation of weight and balance?

Answer 22

A force that tends to cause rotation. It is the product of the weight of an object in pounds and the distance of the object from the datum in inches.

Question 23

How do you find the moment of an item installed in an aircraft?

Answer 23

Multiply the weight of the item in pounds by its distance from the datum in inches.

Question 24

What is meant by the arm of an item installed in an aircraft?

Answer 24

The distance, in inches, between the center of gravity of the item and the datum.

Question 25

Where do you find the arm of an item installed in an aircraft?

Answer 25

In the Type Certificate Data Sheets for the aircraft.

Question 26

What is meant by a moment index?

Answer 26

A moment divided by a constant such as 10, 100, or 1,000.

Question 27

What is meant by the center of gravity range?

Answer 27

The distance in inches between the forward allowable center of gravity and the rearward allowable center of gravity.

Question 28

What is the significance of the empty weight center of gravity range of an aircraft?

Answer 28

If the empty weight center of gravity falls within the EWCG range, the aircraft cannot be legally loaded in such a way that its loaded center of gravity will fall outside of the allowable loaded CG range. Not all aircraft have an EWCG range.

Question 29

Why is the empty weight center of gravity range not given in the Type Certificate Data Sheets for some aircraft?

Answer 29

The empty weight center of gravity range is given only for aircraft that cannot be legally loaded in such a way that their loaded center of gravity will fall outside of the allowable limits.

Question 30

What is meant by the mean aerodynamic chord (MAC)?

Answer 30

The chord of an imaginary airfoil that has the same aerodynamic characteristics as the actual airfoil.

Question 31

What is a loading envelope?

Answer 31

The enclosed area on a graph of an airplane’s loaded weight and CG location. If lines drawn from the weight and CG cross within this envelope the airplane is properly loaded.

Question 32

What is meant by permanent ballast for an aircraft?

Answer 32

Weight that is permanently installed in an aircraft to bring the empty weight center of gravity into allowable limits.

Question 33

Where must a record be kept of the current empty weight and the current center of gravity of an aircraft?

Answer 33

In the aircraft flight manual or weight and balance records required by 14 CFR 23.1583.