Entering Performance parameters
Aircraft CG and ZFW
Before any flight, the aircraft weights must be entered into the MCDU in order to allow it to calculate the performance values for the flight plan. These weight values are entered on the INIT B page, whilst the aircraft is on the ground and before the engines are running.
The values to be entered are :
Zero Fuel Weight (ZFW)
Press the INIT button on the MCDU and then the Next page arrow on the MCDU to get to the INIT B page,
Write the CG and ZFW into the scratch pad as CG/ZFW eg 34/150
Press LSK 1R to enter it into the MCDU
On the FMGS Aid, the current ZFW and CG values are displayed in the Info Display Area
On the actual aircraft these values will have come from the aircraft loading sheet, or equivalent.
Write the Fuel on board value into the scratch pad eg 25
Press LSK 2R to enter it into the MCDU.
It is also possible for the MCDU to calculate the block fuel requirement. The way to do this is detailed in the Block fuel function description of the MCDU
Entering the V Speeds
The takeoff speeds are entered in the MCDU prior to take off. The take off speeds are :
V1
The SRS mode will guide the aircraft to maintain V2+10 after take off. If no V2 speed is entered, the SRS mode is unavailable.
The Performance Take off page shows box entries for V1, VR and V2, meaning that they must be filled in by the flight prior to take off.
Press the PERF key on the MCDU to show the Take off performance page.
Write the V1 speed into the scratch pad eg 123
Press LSK 1L to enter it into the MCDU
Write the VR speed into the scratch pad eg 145
Press LSK 2L to enter it into the MCDU
Write the V2 speed into the scratch pad eg 159
Press LSK 3L to enter it into the MCDU
The V speeds, when entered are shown in blue. And on the PFD they are shown as numbers or as the figure 1 ( for V1) and a magenta circle for VR)
The following parameters should also be checked and modified if appropriate.
Thrust Reduction altitude
Acceleration altitude
Engine out acceleration altitude
Transition altitude
Flaps and THS entries are for reference only.
Entering a temperature will allow the Flex T/O mode to engage.
The thrust reduction altitude is where the LVR CLB FMA will be annunciated and where
the throttle levers should be pulled back from MCT or Max T/O to the Climb detent.
This is done automatically when using the Auto T/O mode of this FMGS Aid, but must
be done manually if using a joystick On the aircraft the thrust levers are moved
back t the CL detent.
Entering Pre select climb speed
This is an optional entry. It is required only if the flight crew wish ( or ATC demands) that a specific climb out speed be used other than the managed speed that the FMGS has computed based on factors including the Cost Index on the INIT A page.
The Pre Select function allows the flight crew to pre select a climb speed when on the ground. This is done on the CLB performance page. If an entry is made, then when the climb phase begins, the MCDU will initialized the FCU with the pre selected speed and the aircraft will then be flown using selected speed mode and not managed
Press the PERF button on the MCDU
Press the next phase prompt to show the CLB performance page
Write the selected climb speed into the scratch pad eg 230
Press LSK 4L to enter it into the MCDU
The pre selected value appears in green, and an asterisk appears against the managed speed.
The pre selected value also appears on the FMA. This is the speed that will be used to initialize SPD window the FCU when the climb phase begins.
To remove the selected speed and return to managed speed before the climb phase is active, simply press the star adjacent to the managed speed value on the climb performance page. If desired during climb phase, simply push the speed knob on the FCU to return managed speeds
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