NORMAL OPERATIONS
CRUISE
A318/A319/A320/A321
FLIGHT CREW TRAINING MANUAL
ALTITUDE CONSIDERATIONS
Applicable to: ALL
The MCDU PROG page displays:
? REC MAX FL
? OPT FL.
REC MAX FL
REC MAX FL reflects the present engine and wing performance and does not take into account the cost aspect. It provides a 0.3 gbuffet margin. If the crew inserts a FL higher than REC MAX into the MCDU, it will be accepted only if it provides a buffet margin greater than 0.2 g. Otherwise, it will be rejected and the message "CRZ ABOVE MAX FL" will appear on the MCDU scratchpad. Unless
there are overriding operational considerations, e.g. either to accept a cruise FL higher than REC MAX or to be held significantly lower for a long period, REC MAX should be considered as the upper cruise limit.
OPT FL
OPT FL displayed on the MCDU is the cruise altitude for minimum cost when ECON MACH is flown and should be followed whenever possible. It is important to note that the OPT FL displayed on the
PROG page is meaningful only if the wind and temperature profile has been accurately entered.
The crew should be aware that flying at a level other than the OPT FL would adversely affect the trip cost.
For each Mach number, there will be a different OPT FL. Should an FMGS failure occur, the crew should refer to the FCOM or QRH to determine the OPT FL. FCOM and QRH charts are only provided for two different Mach numbers.
STEP CLIMB
Criteria: SA
9 Applicable to: MSN 0045-0499
Since the optimum altitude increases as fuel is consumed during the flight, from a cost point of view, it is preferable to climb to a higher cruise altitude when the aircraft weight permits. This technique,
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