Midterm

• The primary purpose of aircraft weight and balance control is SAFETY
• Primary reasons why aircraft become heavier as they become older:

  -         Repair

  -         Alteration

  -         Replacement-aircraft parts

  -         Modification
• The two basic types of scales used to weigh aircraft are platform and load cell:

  -         Mechanical platform scale

  -         Electronic/Load cell scale
• Mechanical platform scale - This weighing scale mostly use for small aircraft. The mechanical platform Scale are low profile, easy to handle, safe, and reliable
• Electronic/Load Cell Scale - This weighing scale mostly use for Helicopter/Narrow/Large transport aircraft. It’s reliable means to weigh aircraft and are typically cheaper than the platform type.
• 12 months – the maximum recognized period between calibration checks
• Tare – the extra weight that must be subtracted from the scale reading
• The major considerations in preparing an aircraft for weighing are described in the following:

  -         Scale Preparation

  -         Weigh clean aircraft inside hangar

  -         Equipment list

  -         Ballast

  -         Standard weights

  -         Draining the fuel

  -         Oil

  -         Other fluids

  -         Configuration of the aircraft

  -         Jacking the aircraft

  -         Leveling the aircraft
• Special precautions - must be taken when raising an aircraft on jacks
• Stress plates - must be installed under the jack pads if the manufacturer specifies them
• Aircraft Jacks - are a vital part of any ground support maintenance program
• Two of the most common types of aircraft jacks:

  -         Axle jacks

  -         Tripod jacks
• Axle Jacks – used for aircraft maintenance involving tire repair and replacement, brake service repair and other maintenance procedures when lifting the nose and/or main landing gear is necessary
• Tripod Jacks – used for routine maintenance on both the nose and fuselage of the aircraft
• Collapsible Tripod Jack - are available, but they’re mostly used for military applications
• MAC - the chord of an imaginary airfoil that has the same aerodynamic characteristics as the actual airfoil
• Chord - is the width of the wing, or straight-line distance from the leading edge to the trailing edge, on an airplane
• MAC - represents the width of an equivalent rectangular wing in given conditions
• MAC is established by the manufacturer, defining its leading edge (LEMAC) and trailing edge (TEMAC) in terms of inches from the datum