Flashcards in Weight and Balance Deck (12)
Define the meaning of "empty weight"
The weight of the airframe, engines, all permanently installed equipment, and unusable fuel. Depending on the the FARs under which the aircraft was certificated, either the undrainable oil or full reservoir oil is included.
Define the meaning of "gross weight"
The maximum allowable weight of both the airplane and contents.
Define the term "useful load"
The weight of the pilot, copilot, passengers, bagage, usable fuel and drainable fuel.
Define the term "arm"
The horizontal distance in inches from a the reference datum line tot he center of gravity of the item.
Define the term "moment"
The product of the weight of an item multiplied by its arm. Moments are expressed in pound-inches.
Define the term "center of gravity"
The point about which an aircraft would balance if it were possible to suspend it at that point. Expressed in inches from datum.
Define the term "datum"
An imaginary vertical plane or line from which all measurements of arm are taken. Establised by the manufacturer.
What basic equation is used in all weight and balance problems to find the CG location of an airplane and/or its components?
Weight x Arm = Moment
Arm (CG) = total Moment divided by total weight
REMEMBER: Weight x Arm = Moment
What performance characteristics will be adversely affected when an aircraft has been overloaded?
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
e) reduced maneuverability
f) Higher stalling speed
i) Higher landing speed
j) Longer landing roll
k) Excessive weight on the nosewheel
What effect does a forward center of gravity have on an aircraft's flight characteristics?
a) Higher stall speed - stalling angle of attack is reached at a higher speed due to increased wing loading
b) Slower cruise speed - increased drag
c) More stable - the CG is farther forward from the center of pressure which increases longitudinal stability.
d) Greater back elevator pressure required - longer takeoff roll; higher approach speeds and problems with landing flare.
What effect does a rearward CG have on an aircraft's flight characteristics?
a) Lower stalling speed - less wing loading
b) Higher cruise speed - reduced drag; smaller angle of attack is required to maintain altitude
c) Less stable - stall and spin recovery more difficult; the center of gravity is closer to the center of pressure, causing longitudinal instability.