Weight & Balance
References
• PHAK Chapter 10 – Weight and Balance, Weight & Balance Handbook, C172/C152/other W&B Sheets and Graphs
Introduction
• Compliance with weight and balance limits of any aircraft is critical to flight safety
• Operating above weight limitations comprises the structural integrity of an aircraft and adversely affects its performance
• Operating outside the approved CG limits results in control difficulty
Overview Video KSDL overweight crash: https://www.youtube.com/watch?v=Ojfs5qOq2yk&feature=youtu.be
• Effects of Weight
• Balance, Stability, and Center of Gravity
o Effects of Adverse Balance
• Management of Weight and Balance Control
• W&B Terms and Definitions (discuss while walking through W&B problem)
• Determining Weight & Balance (walk through example)
o Methods, Weight Shifting (formulas), Weight Addition or Removal (formulas), Weight & Balance Restrictions
Effects of Excess Weight
Excess weight reduces the flight performance in almost every respect, reducing the safety margins available to the pilot:
Higher takeoff speed d/t higher stall speed
Longer takeoff run Takes longer to accelerate airplane to takeoff speed
Reduced rate and angle of climb Any increase in weight produces a proportional decrease in climb rate (trying to lift
heavier weight with same amount of power)
Lower maximum altitude/ceiling more spread out air molecules (less lift), wing is less effective, can't carry weight as high
Shorter cruise range Higher angle of attack (more drag), fuel burn increases with gross weight
Reduced cruising speed Equal thrust, trying to move a greater weight through air envelope (car dragging trailer)
Reduced maneuverability Increased weight, greater load factor on wing
Higher stalling speed d/t higher stall speed
Higher approach and landing d/t higher stall speed
speed
Longer landing roll More inertia and speed required on final requires longer roll
Excessive weight on nose wheel Upon landing, increased weight causes greater downforce on aircraft structures
& gear
• Preflight planning should include a check of performance charts to determine if the aircraft’s weight may contribute to
hazardous flight situations
• Most aircraft are designed, when all seats are occupied, baggage compartment is full, and all fuel tanks are full, the aircraft
is grossly overloaded
• Overweight Boeing 727 CRASH at Colombia: https://www.youtube.com/watch?v=EnfQJfsY2Po
Management of Weight and Balance Control
• Aircraft manufacturers provide weight and balance limitations in the AFM
• FAR 91.9 requires the PIC to comply with the operating limits in the approved AFM
o Before any flight, the pilot should determine the weight and balance condition of the aircraft
• The pilot controls two variables that affect weight and balance:
o Loading (People/Cargo)
o Fuel Management
• Weight and balance records must be updated when equipment changes are made
• In most aircraft, it is not possible to fill all seats, baggage compartments, and fuel tanks, and remain within the approved
weight and balance limits.
1
References
• PHAK Chapter 10 – Weight and Balance, Weight & Balance Handbook, C172/C152/other W&B Sheets and Graphs
Introduction
• Compliance with weight and balance limits of any aircraft is critical to flight safety
• Operating above weight limitations comprises the structural integrity of an aircraft and adversely affects its performance
• Operating outside the approved CG limits results in control difficulty
Overview Video KSDL overweight crash: https://www.youtube.com/watch?v=Ojfs5qOq2yk&feature=youtu.be
• Effects of Weight
• Balance, Stability, and Center of Gravity
o Effects of Adverse Balance
• Management of Weight and Balance Control
• W&B Terms and Definitions (discuss while walking through W&B problem)
• Determining Weight & Balance (walk through example)
o Methods, Weight Shifting (formulas), Weight Addition or Removal (formulas), Weight & Balance Restrictions
Effects of Excess Weight
Excess weight reduces the flight performance in almost every respect, reducing the safety margins available to the pilot:
Higher takeoff speed d/t higher stall speed
Longer takeoff run Takes longer to accelerate airplane to takeoff speed
Reduced rate and angle of climb Any increase in weight produces a proportional decrease in climb rate (trying to lift
heavier weight with same amount of power)
Lower maximum altitude/ceiling more spread out air molecules (less lift), wing is less effective, can't carry weight as high
Shorter cruise range Higher angle of attack (more drag), fuel burn increases with gross weight
Reduced cruising speed Equal thrust, trying to move a greater weight through air envelope (car dragging trailer)
Reduced maneuverability Increased weight, greater load factor on wing
Higher stalling speed d/t higher stall speed
Higher approach and landing d/t higher stall speed
speed
Longer landing roll More inertia and speed required on final requires longer roll
Excessive weight on nose wheel Upon landing, increased weight causes greater downforce on aircraft structures
& gear
• Preflight planning should include a check of performance charts to determine if the aircraft’s weight may contribute to
hazardous flight situations
• Most aircraft are designed, when all seats are occupied, baggage compartment is full, and all fuel tanks are full, the aircraft
is grossly overloaded
• Overweight Boeing 727 CRASH at Colombia: https://www.youtube.com/watch?v=EnfQJfsY2Po
Management of Weight and Balance Control
• Aircraft manufacturers provide weight and balance limitations in the AFM
• FAR 91.9 requires the PIC to comply with the operating limits in the approved AFM
o Before any flight, the pilot should determine the weight and balance condition of the aircraft
• The pilot controls two variables that affect weight and balance:
o Loading (People/Cargo)
o Fuel Management
• Weight and balance records must be updated when equipment changes are made
• In most aircraft, it is not possible to fill all seats, baggage compartments, and fuel tanks, and remain within the approved
weight and balance limits.
1
