Page 259 - UK Air Operations Regulations 201121

Part CAT - ANNEX IV - Commercial Air Transport Operations
CAT.OP.MPA.145
CAT.OP.MPA.145(a) AMC1 Establishment of minimum flight altitudes
CAT.OP.MPA.145(a) AMC1.1 Establishment of minimum flight altitudes
20th November 2021
for the time required to fly from the critical point to an alternate
aerodrome; or
c) at the single-engine ceiling, provided that the aeroplane is type
certified to operate above flight level 450;
(B) descend and hold at 1 500 ft for 15 minutes in international standard
atmosphere (ISA) conditions;
(C) descend to the applicable MDA/DH followed by a missed approach
(taking into account the complete missed approach procedure);
followed by
(D) a normal approach and landing.
(ii) Ice protection: additional fuel used when operating in icing conditions (e.g.
operation of ice protection systems (engine/airframe as applicable)) and,
when manufacturer’s data are available, take account of ice accumulation on
unprotected surfaces if icing conditions are likely to be encountered during a
diversion.
(iii) APU operation: if an APU has to be used to provide additional electrical power,
consideration should be given to the additional fuel required.
(2) Communication facilities: the availability of communications facilities in order to allow
reliable two-way voice communications between the aeroplane and the appropriate
ATC unit at OEI cruise altitudes.
(3) Aircraft technical log review to ensure proper MEL procedures, deferred items, and
required maintenance checks completed.
(4) ERA aerodrome(s): ensuring that ERA aerodromes are available for the intended
route, within the distance flown in 180 minutes based upon the OEI cruising speed
which is a speed within the certificated limits of the aeroplane, selected by the
operator and approved by the CAA, confirming that, based on the available
meteorological information, the weather conditions at ERA aerodromes are at or
above the applicable minima for the period of time during which the aerodrome(s)
may be used.
Table 1 Planning minima
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[1] Commission Regulation (EC) No 2042/2003 of 20 November 2003 on the continuing airworthiness
of aircraft and aeronautical products, parts and appliances, and on the approval of organisations and
personnel involved in these tasks (OJ L 315, 28.11.2003, p. 1).
Establishment of minimum flight altitudes
(a) The operator shall establish for all route segments to be flown:
(1) minimum flight altitudes that provide the required terrain clearance, taking into
account the requirements of Subpart C; and
(2) a method for the flight crew to determine those altitudes.
(b) The method for establishing minimum flight altitudes shall be approved by the CAA.
(c) Where the minimum flight altitudes established by the operator and a State overflown
differ, the higher values shall apply.
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.
CONSIDERATIONS FOR ESTABLISHING MINIMUM FLIGHT ALTITUDES
This AMC provides another means of complying with the rule for VFR operations of other-than-
complex motor-powered aircraft by day, compared to that presented in AMC1 CAT.OP.MPA.145(a).
The safety objective should be satisfied if the operator ensures that operations are only conducted
along such routes or within such areas for which a safe terrain clearance can be maintained and take
account of such factors as temperature, terrain and unfavourable meteorological conditions.
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