Altitude Constraints
If necessary, the FAF altitude constraint may be modified and set above or below the published FAF altitude.
After an approach procedure has been loaded into the flight plan, any altitude constraint programmed at the airport reference point (on the flight plan just ahead of the approach procedure) will be removed if the approach procedure is changed or removed.
An altitude constraint may be displayed as a flight level (FL), height above mean sea level (MSL), or height above ground level (AGL). AGL format is only available for airport and runway waypoints when the radio altimeter is installed.
The type of altitude constraint shall be identified by the presence of constraint bars above and/or below the altitude. The vertical profile shall consider altitude constraints which must be crossed at the specified altitude, as well as complex altitude constraints (At or Above / Between / At or Below). Except during VNAV direct-to operations, the vertical profile considers all altitude constraints and creates an optimized profile descent from the TOD at the cruise altitude to the last descent constraint in the flight plan.
When creating an altitude constraint, the Phase Button will default to Climb or Descent based upon the location in the flight plan of the waypoint being modified. If the waypoint is before the last climb constraint, the phase will default to Climb. If the waypoint is after a descent constraint, the phase will default to Descent. If the waypoint is located between the last climb constraint and the first descent constraint, the default will be determined based on the aircraft altitude, length of the flight plan, and existing constraints.