Initialization and Flight Planning
Figure 009
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The altitude constraints at the waypoints
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The speed constraints also at the waypoints
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The CMS (Constant Mach Segment) for the cruise phase only
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The time constraint the pilot may introduce (NOTE 1)
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The speed limits (e.g. 250 kts below 10,000 ft.) in climb and descent phase
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The cruise flight levels and possibly step climb/descent
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The cost index for this flight plan, which permits to take into account both time cost and fuel cost in optimization computation.
All these lateral and vertical elements are or may be defined during initialization. They may be included in the navigation data base which is resident in the FMS. They may also be contained in a specific record with a specific name (Company route) and therefore can be initialized by entering the company route number in the INIT page.
NOTE : The whole paragraph above does not apply to these elements.
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It has to be noted that the navigation data base includes therefore all the elements allowing the construction of company routes. In addition, to allow flight plan modifications by the crew, the data base contains also a set of waypoints, navaids and airports in the region covered by the data base. Together with the airports, the departure/arrival procedures are also defined even if not part of any company route. The file of navaids is also used for the navaid autotune function described later. Besides the nav data base, there is a performance data base containing various data corresponding to the aircraft and engine models. This performance data base is used for the performance functions.
Once introduced in the system, the flight plan may be displayed on the MCDU (F. PLN pages) and on the ND in the ARC, ROSE-NAV and PLAN modes.
(3) Flight plan modifications Flight plan modifications can then be performed by the crew.
Two types of F-PLN revisions exist:
(a) Lateral revisions
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Insertion or deletion of a waypoint in the F-PLN.
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Insertion of a leg to fly direct to a waypoint (NOTE 2).
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Introduction or modification of a departure procedure either partially or entirely.
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Introduction or modification of an arrival procedure either partially or entirely.
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Modification of the destination.
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Modification of the alternate F-PLN.
-Activation of the alternate F-PLN.
-Insertion of an airway from a F-PLN waypoint down to a specific waypoint or down to intersection of another airway.
-Creation of an offset path.
-Insertion or deletion of a holding pattern.
-Activation of the engine out SID.
NOTE : All the modifications of the lateral F-PLN except DIRECT
____ TO require the insertion of a temporary F-PLN which is displayed on the MCDU and the ND.
(b) Vertical revisions
-Insertion, modification or deletion of any altitude or speed or time constraints or Constant Mach Segment (CMS) in the F-PLN.
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The same for speed limits in climb and/or descent phase.
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The same for a step climb or descent in cruise.
In addition the crew can modify the cruise flight level, the cost index, the takeoff/go around altitudes and insert estimated winds along the F-PLN.
(4) Secondary flight plan The crew has also the possibility
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to init the F-PLN ground request
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to create a SECONDARY FLIGHT PLAN.
This SEC F.PLN which has exactly the same structure as the ACTIVE
F.PLN may be used for several functions:
-Preparation of a second departure procedure before takeoff, when this one is defined late.
-Evaluation of alternate performance functions, in particular, in view of reclearance flights.
-Preparation of the next flight while in flight. This includes the fuel planning function.
-Training.
The SEC F.PLN may be created either by copying the active F.PLN or by initialization as for the active F.PLN. It may then be displayed on the MCDU (SEC F.PLN pages) and on the ND with a specific color. When created, the SEC F.PLN may be activated under certain conditions.
B. Lateral Functions Three main items make part of the FMS lateral functions. They are:
-Navigation (aircraft position)
-Radio navigation and tuning
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