Weight and Balance

Question 1

What performance characteristics will be adversely affected when an aircraft has been overloaded?

Answer 1

a. Higher takeoff speed.
b. Longer takeoff run.
c. Reduced rate and angle of climb.
d. Lower maximum altitude.
e. Shorter range.
f. Reduced cruising speed.
g. Reduced maneuverability.
h. Higher stalling speed.
1. Higher approach and landing speed.
J. Longer landing roll.
k. Excessive weight on the nosewheel.

Question 2

If the weight and balance of an aircraft has changed due to the addition or removal of fixed equipment in the aircraft, what responsibility does the owner or operator
have?

Answer 2

• make appropriate entries in the aircraft records
• proper notations made in weight and balance records.

Question 3

What is the purpose of form “Major Repairs and Alterations” (FAA Form 337).

Answer 3

Owner or operator uses it to record any repairs or modificationsthat affecting weight and balance

Question 4

Define the term “center of gravity.”

Answer 4

• point about which an aircraft would balance if it were possible to support the aircraft at that point.
• The CG must be within specific limits for safe flight.

Question 5

What effect does a forward center of gravity have on an aircraft’s flight characteristics?

Answer 5

• *Higher stall speed** - Stalling angle of attack reached at a higher speed due to increased wing loading.
• *Slower cruise speed** - Increased drag, greater angle of attack required to maintain altitude.
• *More stable** -The center of gravity is further forward from the center of pressure, which increases longitudinal stability.
• *Greater back elevator pressure required** - Longer takeoff roll, higher approach speeds and problems with the landing flare.

Question 6

What effect does an aft center of gravity have on an
aircraft’s flight characteristics? (FAA-H-8083-25)

Answer 6

• *Lower stall speed:** Less wing loading.
• *Higher cruise speed:** Reduced drag, smaller angle of attack required to maintain altitude.
• *Less stable** - Stall and spin recovery more difficult; when angle of attack is increased it tends to result in additional increased angle of attack.

Question 7

Arm

Answer 7

The horizontal distance in inches from the reference datum
line to the center of gravity of an item.

Question 8

Basic empty weight (GAMA) -

Answer 8

The standard empty weight plus
optional and special equipment that has been installed.

Question 9

Center of gravity limits

Answer 9

The specified forward and aft or lateral
points beyond which the CG must not be located during takeoff,
flight or landing.

Question 10

Center of gravity range

Answer 10

The distance between the forward and
aft CG limits indicated on pertinent aircraft specifications.

Question 11

Datum

Answer 11

An imaginary vertical plane or line from which
all measurements of arm are taken. It is established by the
manufacturer.

Question 12

Floor load limit

Answer 12

The maximum weight the floor can sustain per
square inch/foot as provided by the manufacturer.

Question 13

Fuel load

Answer 13

The expendable part of the load of the aircraft. It
includes only usable fuel, not fuel required to fill the lines or that
which remains trapped in the tank sumps.

Question 14

Licensed empty weight

Answer 14

The empty weight that consists of the
airframe, engine(s), unusable fuel, and undrainable oil plus standard
and optional equipment as specified in the equipment list. Some
manufacturers used this term prior to GAMA standardization

Question 15

Maximum, landing weight

Maximum ramp weight

Maximum takeoff weight

Answer 15

Maximum, landing weight - The maximum weight at which the
aircraft may normally be landed. The maximum landing weight
may be limited to a lesser weight when runway length or atmospheric
conditions are adverse.
Maximum ramp weight-The total weight of a loaded aircraft, and
includes all fuel. It is greater than the takeoff weight due to the fuel
that will be burned during the taxi and runup operations. Ramp
weight may also be referred to as taxi weight.
Maximum takeoff weight - The maximum allowable weight at the
start of the takeoff run. Some aircraft are approved for loading to a
greater weight (ramp or taxi) only to allow for fuel burnoff during
ground operation. The takeoff weight for a particular flight may be
limited to a lesser weight when runway length, atmospheric conditions,
or other variables are adverse.

Question 16

Maximum weight

Answer 16

The maximum authorized weight of the
aircraft and all of its equipment as specified in the Type Certificate
Data Sheets (TCDS) for the aircraft

Question 17

Maximum zero fuel weight (GAMA)

Answer 17

maximum weight,
exclusive of usable fuel.

Question 18

Mean aerodynamic chord (MAC)

Answer 18

The average distance from
the leading edge to the trailing edge of the wing. The MAC is
specified for the aircraft by determining the average chord of an
imaginary wing which has the same aerodynamic characteristics
as the actual wing.

Question 19

Moment

Answer 19

Moment - The product of the weight of an item multiplied by its
arm. Moments are expressed in pound-inches.

Question 20

Moment index

Answer 20

• A moment divided by a constant such as 100,
  1,000, or 10,000. The purpose of using a moment index is to
  simplify weight and balance computations of large aircraft where
  heavy items and long arms result in large, unmanageable numbers

Question 21

Payload (GAMA)

Answer 21

The weight of occupants, cargo, and baggage

Question 22

Standard empty weight (GAMA)

Answer 22

The airframe, engines, and
all items of operating equipment that have fixed locations and
are permanently installed in the airplane; including fixed ballast,
hydraulic fluid , unusable fuel, and full engine oil.

Question 23

Station -

Answer 23

A location in the aircraft which is identified by a number
designating its distance in inches from the datum. The datum is,
therefore, identified as station zero. The station and arm are usually
identical. An item located at station +50 would have an arm of 50
inches.

Question 24

Useful load -

Answer 24

The weight of the pilot, copilot, passengers,
baggage, usable fuel and drainable oil. It is the empty weight
subtracted from the maximum allowable takeoff weight. The term
applies to general aviation aircraft only.

Question 25

What basic equation is used in all weight and balance
problems to find the center of gravity location of an
airplane and/or its components?

Answer 25

Weight x Arm = Moment
By rearrangement of this equation to the forms,
Weight = Moment -:- arm.
Arm = Moment -:- weight.
CG = Moment -:- weight.
With any two known values, the third value can be found.

Question 26

What basic equation is used to determine center of
gravity?

Answer 26

Center of gravity is determined by dividing total moments by total
weight.

Question 27

Explain the term percent of mean aerodynamic chord
(MAC).

Answer 27

• common practice in larger aircraft.
• The CG position is expressed as a percent MAC (percent of mean aerodynamic chord), and the CG limits are expressed in the same manner.
• Normally, an aircraft will have acceptable flight characteristics if the CG is located somewhere near the 25% average chord point. This means the CG is located one-fourth of the total distance back from the leading edge of the average wing section.

Question 28

If the weight of an aircraft is within takeoff limits but the
CG limit has been exceeded, what actions can the pilot
take to correct the situation?

Answer 28

The most satisfactory solution to this type of problem is to shift
baggage, passengers, or both in an effort to make the aircraft CG
fa ll within limits.

Question 29

When a shift in weight is required, what standardized
and simple calculations can be made to determine the
new CG?

A typical problem may involve calculation of a new CG for an
aircraft which has shifted cargo due to the CG being out of limits.
Given:
Aircraft total weight.. ……………. 6,680 pounds
CG .. .. ………. … ………….. ……… ….. Station 80.0
CG limits ……………. .. …… ……….. Station 70-78

Find: What is the location of the CG if 200 pounds is shifted from
the aft compartment at station 150 to the forward at station 30?

Answer 29

Question 30

If the weight of an aircraft changes due to the addition or
removal of cargo or passengers before flight, what
formula may be used to calculate new CG?
(FAA-H-8083-25)
A typical problem may involve the calculation of a new CG for an
aircraft which, when loaded and ready for flight, receives some
additional cargo or passengers just before departure time.
Given:
Aircraft total weight.. ………… …. 6,860 pounds
CG …………… …… ……. …………….. Station 80.0
Find: What is the location of the CG if 140 lbs. of baggage is
added to station 150?

Answer 30