AMC2 CAT.POL.MAB.100(b) Mass and balance, loading
CAA ORS9 Decision No. 1
FLEET MASS AND CG POSITION — AEROPLANES
(a) For a group of aeroplanes of the same model and configuration, an average dry operating mass and CG position may be used as the fleet mass and CG position, provided that:
(1) the dry operating mass of an individual aeroplane does not differ by more than ±0.5 % of the maximum structural landing mass from the established dry operating fleet mass; or
(2) the CG position of an individual aeroplane does not differ by more than ±0.5 % of the mean aerodynamic chord from the established fleet CG.
(b) The operator should verify that, after an equipment or configuration change or after weighing, the aeroplane falls within the tolerances above.
(c) To add an aeroplane to a fleet operated with fleet values, the operator should verify by weighing or calculation that its actual values fall within the tolerances specified in (a)(1) and (2).
(d) To obtain fleet values, the operator should weigh, in the period between two fleet mass evaluations, a certain number of aeroplanes as specified in Table 1, where ‘n’ is the number of aeroplanes in the fleet using fleet values. Those aeroplanes in the fleet that have not been weighed for the longest time should be selected first.
Table 1
Minimum number of weighings to obtain fleet values
Number of aeroplanes in the fleet |
Minimum number of weighings |
---|---|
2 or 3 |
n |
4 to 9 |
(n + 3)/2 |
10 or more |
(n + 51)/10 |
(e) The interval between two fleet mass evaluations should not exceed 48 months.
(f) The fleet values should be updated at least at the end of each fleet mass evaluation.
(g) Aeroplanes that have not been weighed since the last fleet mass evaluation may be kept in a fleet operated with fleet values, provided that the individual values are revised by calculation and stay within the tolerances above. If these individual values no longer fall within the tolerances, the operator should determine new fleet values or operate aeroplanes not falling within the limits with their individual values.
(h) If an individual aeroplane mass is within the dry operating fleet mass tolerance but its CG position exceeds the tolerance, the aeroplane may be operated under the applicable dry operating fleet mass but with an individual CG position.
(i) Aeroplanes for which no mean aerodynamic chord has been published, should be operated with their individual mass and CG position values. They may be operated under the dry operating fleet mass and CG position, provided that a risk assessment has been completed.