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► An aeroplane is weighed and the following recordings are made: nose wheel assembly scale 5330 kg, left main wheel assembly scale 12370 kg, right main wheel assembly scale 12480 kg. If the "operational items" amount to a mass of 1780 kg with a crew mass of 545 kg, the empty mass, as entered in the weight schedule, is:
A) 32 505kg
B) 28 400kg
C) 31 960kg
D) 30 180kg
5330 + 12370 + 12480 = 30 180kg
(Operational items and crew masses do not below to the "empty mass" of an aeroplane)
► An aeroplane with a two wheel nose gear and four main wheels rests on the ground with a single nose wheel load of 500kg and a single main wheel load of 6000kg. The distance between the nose wheels and the main wheels is 10 meter. How far is the centre of gravity in front of the main wheels?
A) 40cm
B) 25cm
C) 4m
D) 41.6cm
Nose wheels = 500kg x 2 = 1000kg
Main wheels = 6000kg x 4 = 24 000kg
Total mass = 25 000kg
With only the main wheels, the CG position would be located at the main wheels (0). If we now add the nose wheel mass the CG will shift forward. Calculate the moment this will create:
Moment = arm x mass
Moment = 10m x 1000kg = 10 000kg/m
CG = Total Moment / Total Mass
CG = 10 000kg/m / 25 000kg
CG = 0.4m (40cm)
► Where is the centre of gravity of the aeroplane in the diagram given:
A) 26.57 cm aft datum
B) 32.29 cm aft datum
C) 26.57 cm forward of datum
D) 32.29 cm forward of datum
Calculate the total mass and total moment. Pay close attention to this one, they put the datum directly on the main wheels (making their arms '0'). The arm of the nose wheel is not 1m but -1.5m forward of datum (2.5m - 1m)
Nose wheel: 1750 x -1.5 = -2625
Left main: 4050 x 0 = 0
Right main: 4080 x 0 = 0
CG = -2625 / 9880
CG = -0.2657m (= -26.57 cm)
! minus symbol indicates FORWARD of the datum
► An operator has a fleet of 43 aircraft, how many aircraft must be weighed at the same time to maintain the fleet value?
A) 6
B) 7
C) 8
D) 9
(X + 51 ) / 10
(43 + 51) / 10 = 9.4 (rounded down to 9)
► An aircraft with a two wheeled nose gear and four main wheels rests on the ground with a single nose wheel load of 725kg and a single main wheel load of 6000kg. The distance between the nose wheels and the main wheels is 10 metres. How far is the centre of gravity in front of the main wheels?
A) 25cm
B) 40cm
C) 57cm
D) 63cm
Nose wheels = 725kg x 2 = 1415kg
Main wheels = 6000 x 4 = 24 000kg
Total mass = 25 415kg
With only the main wheels, the CG position would be located at the main wheels (0). If we now add the nose wheel mass the CG will shift forward. Calculate the moment this will create:
Moment = arm x mass
Moment = 10m x 1415kg
Moment = 14 150kg/m
CG = Total moment / Total mass
CG = 14150kg/m / 25415kg
CG = 0.56m (= 56cm)
► The weights measured at the landing gear of an aircraft are as follows:
Nose wheel (55 inches aft of datum): 475 lbs
Right main wheel (121 inches aft of datum): 1046 lbs
Left main wheel (121 inches aft of datum): 1040 lbs
The CG of the aircraft is:
A) 104.6 in
B) 106.4 in
C) 108.8 in
D) 105.2 in
Nose wheel = 475 x 55 = 26 125
Right main = 1046 x 121 = 126 566
Left main = 1040 x 121 = 125 840
CG = total moment / total mass
CG = 278531 / 2561
CG = 108.8
► Calculate the centre of gravity for the aircraft in the diagram, given:
Nose wheel weight: 7800kg
Left wheel weight: 11800kg
Right wheel weight: 11400kg
A) 0.31 m aft of datum
B) 2.8 m aft of datum
C) 8.2 m aft of datum
D) 3.2 m aft of datum
Don't forget that a mass forward of datum creates a negative moment!
Nose wheel = 7800 x (-7.5m) = -58 500
Left wheel = 11 800 x 6.8 = 80 240
Right wheel = 11 400 x 6.8 = 77 520
CG = total moment / total mass
CG = 99 260 / 31 000
CG = 3.2m
A) 32 505kg
B) 28 400kg
C) 31 960kg
D) 30 180kg
5330 + 12370 + 12480 = 30 180kg
(Operational items and crew masses do not below to the "empty mass" of an aeroplane)
► An aeroplane with a two wheel nose gear and four main wheels rests on the ground with a single nose wheel load of 500kg and a single main wheel load of 6000kg. The distance between the nose wheels and the main wheels is 10 meter. How far is the centre of gravity in front of the main wheels?
A) 40cm
B) 25cm
C) 4m
D) 41.6cm
Nose wheels = 500kg x 2 = 1000kg
Main wheels = 6000kg x 4 = 24 000kg
Total mass = 25 000kg
With only the main wheels, the CG position would be located at the main wheels (0). If we now add the nose wheel mass the CG will shift forward. Calculate the moment this will create:
Moment = arm x mass
Moment = 10m x 1000kg = 10 000kg/m
CG = Total Moment / Total Mass
CG = 10 000kg/m / 25 000kg
CG = 0.4m (40cm)
► Where is the centre of gravity of the aeroplane in the diagram given:
A) 26.57 cm aft datum
B) 32.29 cm aft datum
C) 26.57 cm forward of datum
D) 32.29 cm forward of datum
Calculate the total mass and total moment. Pay close attention to this one, they put the datum directly on the main wheels (making their arms '0'). The arm of the nose wheel is not 1m but -1.5m forward of datum (2.5m - 1m)
Nose wheel: 1750 x -1.5 = -2625
Left main: 4050 x 0 = 0
Right main: 4080 x 0 = 0
CG = -2625 / 9880
CG = -0.2657m (= -26.57 cm)
! minus symbol indicates FORWARD of the datum
► An operator has a fleet of 43 aircraft, how many aircraft must be weighed at the same time to maintain the fleet value?
A) 6
B) 7
C) 8
D) 9
(X + 51 ) / 10
(43 + 51) / 10 = 9.4 (rounded down to 9)
► An aircraft with a two wheeled nose gear and four main wheels rests on the ground with a single nose wheel load of 725kg and a single main wheel load of 6000kg. The distance between the nose wheels and the main wheels is 10 metres. How far is the centre of gravity in front of the main wheels?
A) 25cm
B) 40cm
C) 57cm
D) 63cm
Nose wheels = 725kg x 2 = 1415kg
Main wheels = 6000 x 4 = 24 000kg
Total mass = 25 415kg
With only the main wheels, the CG position would be located at the main wheels (0). If we now add the nose wheel mass the CG will shift forward. Calculate the moment this will create:
Moment = arm x mass
Moment = 10m x 1415kg
Moment = 14 150kg/m
CG = Total moment / Total mass
CG = 14150kg/m / 25415kg
CG = 0.56m (= 56cm)
► The weights measured at the landing gear of an aircraft are as follows:
Nose wheel (55 inches aft of datum): 475 lbs
Right main wheel (121 inches aft of datum): 1046 lbs
Left main wheel (121 inches aft of datum): 1040 lbs
The CG of the aircraft is:
A) 104.6 in
B) 106.4 in
C) 108.8 in
D) 105.2 in
Nose wheel = 475 x 55 = 26 125
Right main = 1046 x 121 = 126 566
Left main = 1040 x 121 = 125 840
CG = total moment / total mass
CG = 278531 / 2561
CG = 108.8
► Calculate the centre of gravity for the aircraft in the diagram, given:
Nose wheel weight: 7800kg
Left wheel weight: 11800kg
Right wheel weight: 11400kg
A) 0.31 m aft of datum
B) 2.8 m aft of datum
C) 8.2 m aft of datum
D) 3.2 m aft of datum
Don't forget that a mass forward of datum creates a negative moment!
Nose wheel = 7800 x (-7.5m) = -58 500
Left wheel = 11 800 x 6.8 = 80 240
Right wheel = 11 400 x 6.8 = 77 520
CG = total moment / total mass
CG = 99 260 / 31 000
CG = 3.2m
