HIGH SPEED WINGS-LEVEL YAW HEADING HOLD
The High Speed Wings-Level Yaw Heading Hold function is active when the
aircraft is flying at high speed (IAS > 45 KIAS) with no FD roll mode engaged
and the selected roll attitude is less than 3°: the function automatically
reduces the roll attitude to 0° (wings level) and then holds new aircraft
heading through the yaw channel.
Yaw channel is also used to correct for heading errors when HDG mode is
engaged on FD (coupled), if the roll attitude is less than 0.5° and heading
error is less than 2°.
The roll attitude is commanded to wings level while yaw is driving heading.
COLLECTIVE CONTROL
The Collective Control function is activated by selecting 3-cue FD operation
or by activating a collective only mode (RHT) while the CLTV/YAW TRIM
switch on the Miscellaneous panel is at ON.
The Collective Control function provides automatic vertical control of the
helicopter by means of a rotary Collective Actuator connected in parallel with
the collective mechanical control system.
When the CLTV/YAW TRIM switch is turned OFF, the collective (and yaw)
Force Trims are disengaged.
Changes to collective reference settings can be performed by repositioning
the collective lever with the collective FTR pressed or using the CLTV beep
switch on the collective grips.
The Collective Control function is disabled by deselecting the mode,
uncoupling the FD from the AP or selecting the SAS mode.
The AP that is controlling the collective actuator is the Trim Master.
The Collective Control function limits collective position to prevent engine or
mast torque exceedances. This limiting function will only be active when the
automatic collective control function is engaged.