MCDU MENU Page
Figure 008
(2) MCDU power up/resets Upon a long-term power up or MCDU switch of, the MCDU extinguishes all annunciators and performs its power up self tests.
If a test failure occurs, the FAIL annunciator comes on if MCDU is switched on, the MCDU healthy discrete output is set to Not Healthy and the MCDU is disabled from further processing. The FAIL annunciator is off if MCDU is off.
If the power up self tests are successfully passed and MCDU is off, the RDY annunciator is on and the MCDU Healthy discrete output is set to Healthy. Further MCDU processing is suspended until the MCDU is set to on, after which the MCDU extinguishes the RDY annunciator and commences its normal operations.
If the power up tests are successfully passed and the MCDU is on, the MCDU commences its normal operations straight-forth.
During the long term-power up, the FAIL annunciators are not on until the MCDU is truly ready or failed, respectively. Additionally, any power loss to the MCDU causes all annunciators to be off and all discrete outputs to be set to their OPEN position.
When MCDU is off, all annunciators are off, all output buses are inactive and all discrete outputs are set on OPEN position.
(3) MCDU overheating and display blanking In order to limit the temperature rise within the MCDU in cases of overheating, a temperature sensor is included to detect when the MCDU is above the normal high temperature and initiates a power saving mode. This mode causes the screen to blank if a MCDU button push has not occurred within the last two minutes.
The scratchpad message MCDU OVERHEATED is displayed for approximately 15 seconds after the screen is blanked, after which it is removed from the display. This message is cleared whenever the screen is unblanked.
The appropriate FM or MCDU MENU annunciators are on whenever a subsystem attempts to send a message to the MCDU while the screen is blanked due to an overheating condition.
3. Operation
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A. Initialization and Flight Planning
(1) Initialization Due to the type of the various functions that the system is performing during the flight, the crew is required to initialize the system by inserting some data via the MCDU. To do so, the pilot must insure the MCDUs are correctly coupled to the FMGCs. The first page displayed by the FMGC at power up on ground or after access through the MCDU MENU page, is the A/C status page which allows the crew to be aware of the FMS status.
Then by selecting the INIT page, the pilot has the possibility to
initialize the FMS.
(Ref. Fig. 009)
The initialization consists of three main functions:
-Select a flight plan which will be the real basis for all computations and displays performed by the FMS.
-Align the IRs by using the position of the airport stored in the FMS data base and called by selection of the flight plan.
-Enter the zero fuel weight (ZFW), center of gravity (CG) and BLOCK fuel as these parameters are used by the FMS to compute guidance speeds and predictions.
The last two functions being self-explanatory, the following explains what a flight plan consists of for the FMS.
(2) Flight plan A flight plan is composed of various elements which indicate the routes the aircraft must follow and the limitations along these routes.
The lateral elements are:
-Origin airport and runway
-Departure procedure including optionally a RWY-SID transition, a SID and an En route transition. The procedures are defined by the various legs and the waypoints between these legs.
-En route airways and waypoints
-Arrival procedure including optionally an En route transition, a STAR (STAR common route + STAR RWY transition), STAR-approach transition, an approach and a missed approach.
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