-Altitude constraint
 -Speed constraint
 -Time constraint
 -Speed limit
 -Estimated takeoff time (origin only)
 -Step (climb or descent)
 -Wind. All elements can be defined or changed through the VERT REV page, but only the first three elements can be modified directly on the F-PLN page. Same mechanization, as described in the following paragraphs, applies for both primary and secondary flight-plans except that INSERT* prompt is cyan for the secondary F-PLN. Access to the VERT REV page is achieved from the F-PLN page when a right line select key is pressed with scratchpad empty at any fixed waypoint, at T/C, T/D or speed limit pseudo waypoints. Access is allowed from the FROM waypoint. After access, if a lateral leg sequence occurs such that the revise point becomes the FROM waypoint, then the revision is aborted and the display reverts to F-PLN page. Access to the VERT REV page is also achieved from the STEP page when DELETE STEP prompt (6R LS key) is selected. Following the flight phase where the revise point is predicted to be, the VERT REV page does not display all fields. Following figure shows different VERT REV pages for access through the FROM waypoint, a fixed waypoint in CLB (ROLLA) and a fixed waypoint in CRZ (PEMAR). (Ref. Fig. 041) Some other vertical revisions are performed directly on the appropriate pages. They deal with CRZ FL, Cost Index, thrust reduction and acceleration altitudes.

 (2)
 Constraints (Ref. Fig. 041) Constraints are displayed on the VERT REV page. They may be defined only at fixed waypoint except the FROM, origin and destination waypoints. In addition, the estimated takeoff time may be entered on the origin VERT REV page.

 (a) On the F-PLN A page Each defined constraint is displayed adjacent to the constrained waypoint, in magenta large font, as long as new predictions are not computed. Then the value of the constraint is replaced by the new predicted value with a star before it.

 VERT REV Pages (with time constraint)
 Figure 041

 Speed and/or altitude constraint may be entered on this page with one of the following format :
 -SPD
 -ALT
 -SPD/ALT. A minus sign must be entered before or after the value for an AT or BELOW altitude, and a plus sign for an AT or ABOVE altitude. A CLB or DES amber prompt may be displayed following the conditions described in Para. 2.B.(3). In this case, the appropriate LS key must be pressed to choose CLB or DES, in order to insert the constraint. If the CLR function is used on a right LS key, all constraints are deleted for the corresponding waypoint.
 (b) On the VERT REV page Each defined constraint is displayed on this page, in large magenta font if it is entered by the pilot or in small magenta font if it is a data base constraint. Format entry and CLB or DES amber prompt display are as described above. (Ref. Fig. 042) If the VERT REV page is exited before choosing CLB or DES for altitude on speed constraint, the prompt will no longer be displayed on the new page, and the constraint will not be accepted.
 (3) Speed Limits A speed limit is a CAS which must not be exceeded below the corresponding speed limit altitude. There can only be two speed limits in a given flight-plan; one for climb and one for descent. On the F-PLN page, both CLB and DES speed limits are displayed as pseudo waypoints when predictions are available. Figures show an example of CLB speed limit (in 4L-4R). On the VERT REV page, only one speed limit is displayed in field 2L. It is the CLB speed limit if the revise point is prior to or at the T/D but the field is dashed if there is no T/D and the aircraft is still in DONE, PREFLIGHT, TAKEOFF, CLB or CRZ flight phase. It is the DES speed limit in all other cases. (Ref. Fig. 013, 014, 041) The system default value of 250 kts below 10,000 ft. applies for both speed limits when there is a flight phase transition to DONE. When origin and destination airports are defined, these values are overwritten by data base speed limits, if they are stored with the associated airports. The pilot may then change both or either of the parameters : speed/ altitude, either on F-PLN or on VERT REV page. If the pilot clears a pseudo waypoint on the F-PLN page, the corresponding speed limit will be deleted from the system.

 Constraints and Step Insertion at CRZ Waypoint
 Figure 042

 A speed limit can also be cleared on the appropriate VERT REV page.
 (4)
 Steps The STEP PRED page is used to insert a step climb or a step descent at a fixed cruise waypoint (FROM excepted) for predictions accuracy purposes. The STEP page is accessed from the VERT REV page with the STEP PRED prompt (4R). (Ref. Fig. 042) If T/C and T/D have not yet been computed, it can be accessed at any fixed waypoint; however if the system predicts that the step cannot be reached within the cruise segment, the step is automatically deleted. Only one step is allowed to exist in a given flight plan. Both the step flight level (mandatory) and the step wind (as an option) must be entered before the step is inserted with the INSERT* prompt (6L). If the RETURN prompt (6R) is selected, the step is not inserted and the display reverts to the previous VERT REV page. A step can be cleared with the DELETE* prompt (6L) on the STEP page, or directly on the F-PLN pages by clearing the S/C or S/D pseudo waypoint. Note that the INSERT prompt is amber for the primary F-PLN and cyan for the secondary F-PLN.
　
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