Climb-out/Enroute
3-11
NOTE
Altitude Capture Needs Achievable Commands
Care should be taken such that a logical set of IAS
(or VS) and ALT targets are selected in order to
capture the desired altitude. For example, if a
negative vertical speed is selected and an altitude
above present aircraft altitude is selected, and then
an Altitude Capture commanded, the autopilot will
attempt to fly at the commanded negative vertical
speed and never cross the targeted altitude, thereby
never transitioning to Altitude Hold mode.
There is also a ‘black out’ period where the autopilot will ignore
the commanded target altitude if it is being edited as the original
target altitude is approached. For example, if the system is
currently performing an altitude capture on departure leg to an
ATC assigned altitude, and as the aircraft is approaching that
original assigned altitude, ATC issues a new assigned altitude
that the pilot is in the process of entering into the system, the
autopilot will ignore the original target and keep climbing to the
new target. As soon as the edit mode is exited, as indicated by
the altitude bug value no longer being reverse-highlighted, the
autopilot will honor whatever target altitude is active in the
system.
The autopilot modes annunciator indication for altitude captures
are a green “
IAS
” or “
VS
” and a cyan “
ALT
”. As the target
altitude is approached, the “IAS” or “VS” annunciators and
buttons on the autopilot control panel extinguish and the “
ALT
”
annunciator and button turns green and flashes for up to 10
seconds indicating the system is capturing the target altitude. At
the end of the flashing period, both the modes annunciator and
the control panel button are displayed in steady green.
