4 / 20

You are departing for a flight with a planned landing fuel of 3000 kg. According to aircraft limitations, the centre tank fuel must be used prior to the wing tank fuel.

Given the following information, the location of the CG on landing will be how many metres aft of the datum?

Maximum Take-Off mass: 99 800 kg
Actual Take-Off Mass: 59 500 kg
Take-off CG location: 16.26 m aft of the datum
Fuel in centre tank at take-off: 16  000 kg
Fuel wing tanks at take-off: 18000 kg
Centre fuel tank centroid: 15.38 m aft of the datum
Wing fuel tank centroid: 17,79 m aft of the datum

  • A

    15.95

  • B

    15.74

  • C

    16.08

  • D

    15.88

These are the formulas we will need to solve this exercise:

Moment = Mass x Arm.
CG = Total Moment / Total Mass.

For this question, we are looking for the CG on landing. Thus, the moment and mass of the burnt fuel must be subtracted from the take-off moment and take-off mass correspondingly, so as to find the Landing Moment and Landing Mass.

The CG on landing is given by the formula: Landing CG = Landing Moment / Landing Mass.

(1) Determine the Landing Moment:

Landing Moment = Take-off Moment - Centre Tank Fuel Moment - Wings Tanks Fuel burnt Moment

  • Take-off Moment = Actual Take-off Mass x Take-off CG Location
Take-off Moment = 59 500 kg x 16.26 m = 967 470 kgm
  • Centre Tank Fuel Moment = Fuel in Centre Tank x Centre fuel Tank Centroid
Centre Tank Fuel Moment = 16 000 kg x 15.38 m = 246 080 kgm
  • Wing Tanks Fuel Burnt Moment = Wing Tanks fuel burnt at landing x Wing Fuel Tank Centroid
Wing Tanks fuel burnt Moment = (18 000 - 3000) kg x 17.79 m = 266 850 kgm


Landing Moment = 967 470 kgm - 246 080 kgm - 266 850 kgm = 454 540 kgm

(2) Determine the Landing Mass:

  • Landing Mass = Actual Take-off Mass - Fuel Centre Tank burnt - Wing Tanks fuel burnt
Landing Mass = 59 500 kg - 16 000 kg - (18 000 - 3000)kg = 28 500 kg

(3) Determine the Landing CG:

  • Landing CG = Landing Moment / Landing Mass
Landing CG = 454 540 kgm / 28 500 kg
Landing CG = 15.95 m

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.

  • Spain
    8
  • Austro Control
    5
  • Greece
    5
  • Poland
    4
  • France
    2
  • Portugal
    2
  • Latvia
    1
  • Luxembourg
    1
Keyboard Shortcut Use Keyboard Shortcuts