ATPL (A)
Review Worksheets
031 MASS & BALANCE
BY KDMN
2020
, I/ UNIT CONVERSION
• 1 lb = 0.45359 kg or 1 kg = 2.2046 lb • 1NM = 1 852 m
• 1 ft = 0.305 cm or 1 m = 3.28ft • 1 USG = 3.785 L
• 1 inch = 2.54 cm • 1ImpG = 4.546 L
01 FUEL DENSITY OR SPECIFIC DENSITY
Published in the flight Manual if the actual fuel density is unknown.
EX: specific gravity = 0.812, What is the mass in lb of 1292L of fuel ?
➔ 1292 x 0.812 = 1049 kg. OR 1 kg = 2.2046 lb -> 1049 kg = 1049 x 2.2046 = 2 313 lb.
II/ MASS
• Masses are defined according to structural, performances and operational aspects.
NB: In this subject, we consider “weight W = mass M”.
01 STRUCTURAL MASS LIMITS
• The following masses are based on the airplane maximum structural capability. These certified masses are
published in the Flight Manual and they are fixed.
a) MAXIMUM TAXI (RAMP) WEIGHT MTW:
➔ It is the maximum mass allowed for movement of the airplane on the ground.
b) MAXIMUM (STRUCTURAL) TAKE-OFF WEIGHT MTOW:
➔ It is the maximum mass allowed at the start of the take-off run.
c) MAXIMUM (STRUCTURAL) LANDING WEIGHT MLW:
➔ It is the maximum mass allowed for a normal landing of the airplane.
d) MAXIMUM ZERO FUEL WEIGHT MZFW:
➔ It is the maximum mass allowed before loading fuel on board.
➔ The mass is limited by the maximum bending moment produced at the wing root (wing/body
intersection).
➔ It is recommended to maintain the fuel CG (=centre of gravity) of the wing at the most outboard
location of the wing.
Review Worksheets
031 MASS & BALANCE
BY KDMN
2020
, I/ UNIT CONVERSION
• 1 lb = 0.45359 kg or 1 kg = 2.2046 lb • 1NM = 1 852 m
• 1 ft = 0.305 cm or 1 m = 3.28ft • 1 USG = 3.785 L
• 1 inch = 2.54 cm • 1ImpG = 4.546 L
01 FUEL DENSITY OR SPECIFIC DENSITY
Published in the flight Manual if the actual fuel density is unknown.
EX: specific gravity = 0.812, What is the mass in lb of 1292L of fuel ?
➔ 1292 x 0.812 = 1049 kg. OR 1 kg = 2.2046 lb -> 1049 kg = 1049 x 2.2046 = 2 313 lb.
II/ MASS
• Masses are defined according to structural, performances and operational aspects.
NB: In this subject, we consider “weight W = mass M”.
01 STRUCTURAL MASS LIMITS
• The following masses are based on the airplane maximum structural capability. These certified masses are
published in the Flight Manual and they are fixed.
a) MAXIMUM TAXI (RAMP) WEIGHT MTW:
➔ It is the maximum mass allowed for movement of the airplane on the ground.
b) MAXIMUM (STRUCTURAL) TAKE-OFF WEIGHT MTOW:
➔ It is the maximum mass allowed at the start of the take-off run.
c) MAXIMUM (STRUCTURAL) LANDING WEIGHT MLW:
➔ It is the maximum mass allowed for a normal landing of the airplane.
d) MAXIMUM ZERO FUEL WEIGHT MZFW:
➔ It is the maximum mass allowed before loading fuel on board.
➔ The mass is limited by the maximum bending moment produced at the wing root (wing/body
intersection).
➔ It is recommended to maintain the fuel CG (=centre of gravity) of the wing at the most outboard
location of the wing.
