AMC1 CAT.OP.MPA.145(a) Establishment of minimum flight altitudes
CAA ORS9 Decision No. 1
CONSIDERATIONS FOR ESTABLISHING MINIMUM FLIGHT ALTITUDES
(a) The operator should take into account the following factors when establishing minimum flight altitudes:
(1) the accuracy with which the position of the aircraft can be determined;
(2) the probable inaccuracies in the indications of the altimeters used;
(3) the characteristics of the terrain, such as sudden changes in the elevation, along the routes or in the areas where operations are to be conducted;
(4) the probability of encountering unfavourable meteorological conditions, such as severe turbulence and descending air currents; and
(5) possible inaccuracies in aeronautical charts.
(b) The operator should also consider:
(1) corrections for temperature and pressure variations from standard values;
(2) ATC requirements; and
(3) any foreseeable contingencies along the planned route.