ISSUE DESCRIPTION
- The predicted range where the turning altitude is reached is way too close. When airborne, it starts to update the point where the constraint altitude is reached, wildly sending the point back and forward with changes in vertical rate at rotation, at acceleration altitude, then flap retraction. It keeps going back and forward.
- The real aircraft makes an accurate prediction on the ground, in flight it hardly changes position, certainly not as violently back and forward with changes in the vertical rate.
- The real aircraft anticipates the turning radius and draws it onto the map display. Because the turn is not drawn, upon reaching the constraint, this thing kind of handles it like a “FLY-OVER” waypoint, it starts turning and intercepts the track from the point the turning altitude was reached to the next waypoint, rather than turning and flying directly to the next waypoint.
- When not selecting an SID in the FMS (just departure runway without departure route), the FMS creates a 1500 ft turning altitude point. When going to the vertical revision page, this “constraint altitude” cannot be modified, it should be green not blue.
FREQUENCY OF ISSUE
Always.
REPRODUCTION STEPS
Select only the departure runway without SID. Open the vertical revision page, observe the altitude constraint can be modified (blue), should not be able to modify the altitude with NAS 3, it should be green instead.
Take-off and observe the constraint moving back and forward violently with the vertical rate changes. Because there is no turn anticipation, upon reaching the constraint altitude, it starts to turn and intercept the track to the next waypoint rather than turning and flying directly to the next waypoint.
YOUR SETTINGS
Not relevant.
MEDIA
Vertical revision page, altitude constraint is supposed to be unmodifiable (green):
On the ground before take-off, note the location of the 1500 ft point, no turning anticipation:
During vertical rate changes (acceleration after take-off and flap retraction):
What it should look like (before take-off), same range setting and flight plan. In-flight, it hardly changes, even through acceleration and flap retraction.
