Copyright D.P. Browne 2011

 

 

 

 

Home.Cockpit.Aircraft Systems.Worked Example.Program Controls.Before Flight.

Altitude Constraint

 

 

Using the Vertical Revision page

 

An altitude constraint may be automatically applied to a waypoint as part of the SID or STAR procedure. A speed constraint may also be manually entered for a waypoint by the flight crew. The altitude  constraint applies to the waypoint it has been created for.

There are 2 ways to enter a altitude  constraint. It may be enter via the the altitude  constraint prompts on a vertical revision page for the waypoint or it may be entered directly ion the flight plan page for the waypoint.

 

Directly on the Flight Plan Page page

 

Select the Flight Plan page by pressing the F-PLN key on the MCDU

 

Select a vertical Revision at the required waypoint

Write the altitude  Limit  value into the scratchpad  

 

 

Enter the input at LSK3R

 

 

 

Select the Flight Plan page by pressing the F-PLN key on the MCDU

 

Write the altitude  Limit  value into the scratchpad

Ensure to write a slash “/” first or else the value will be interpreted as a speed constraint.

Examples :

/2500

/+FL320

/-1500

Enter the input using the right LSK next to the required waypoint.

 

 

 

Page the flight plan Up/Down as required to put the required waypoint in view on the flight plan page

 

A altitude  constraint may will be shown as its actual value in magenta on the flight plan, if performance calculations have not yet been enabled. Thereafter, a magenta astrix will appear by the altitude value for the waypoint with a altitude  constraint.

 

Altitude constraints are

 

 

 

At Altitude

 

At or Above Altitude

At or Below Altitude

 

 

2500

+2500

-2500

Constraints show up on the ND as circled waypoints. The actual constraint Above, At or below is shwon next to them

 

/+Altitude means At or Above

 

 

 

/-Altitude means At or Above

 

 

 

/Altitude means At altitude

 

 

 

Clearing a constraint

 

A speed, altitude or RTA constraint for any waypoint, may be cleared by selecting the CLR button and the Right LSK associated with the waypoint on the flight plan page. Note that this action clears all the constraints for the waypoint.