Eads eurocopter AS 365 N3 - 2.2 Lateral Upper Modes

COMPLEMENTARY FLIGHT MANUAL
AS 365 N3
7.13
10-40 Page 11
2.2 LATERAL UPPER MODES
2.2.1 General
- For all lateral modes (NAV, VOR, LOC) engagement is inhibited below 35 kt.
- For HDG, engagement is inhibited below 26 kt.
- For all lateral modes, engagement is inhibited when aircraft is on ground.
2.2.2 Heading select (HDG)
The HDG mode maintains the current heading upon engagement or
acquires and holds a pre-selected heading.
The HDG mode is engaged/disengaged by pressing the “HDG” rotary knob
on APMS.
When the HDG mode is engaged iHDGi label is displayed on AFCS strip.
Conditions that force the HDG mode disengagement:
- AP disengagement,
- AHRS discrepancy,
- loss of roll axis (loss of cyclic auto-trim or cyclic trim feel permanent
release),
- upper modes disengagement via coupler release push-button on any
cyclic grip,
- complete loss of heading for at least 30 s.
- anomaly detected by the monitoring of the data sent to the FDS for
display to the pilot.
The engagement of the NAV, VOR, LOC, HOV (*) or GSPD (*) modes
disengages the HDG mode.
(*) SAR option
2.2.3 VOR navigation mode (VOR)
The VOR mode acquires and holds a pre-selected VOR course. Coupling
can be done on ND display type.
It presents four possible different phases:
- armament when the VOR deviation is valid but too large, the pilot has to
select a heading that will enable the aircraft to intercept the desired VOR
course within a recommended range of 90 degrees,
- depending on the deviation closing rate, the mode will first align the
aircraft (capture phase), and then, again depending on the closing rate,
will complete the alignment on the selected course (tracking phase),
- loss of bearing validity or rapid deviation change: the VOR reception can
be lost for significant periods of time; also when flying above the VOR
beacon, the VOR bearing exhibits fast and large amplitudes variations.
Therefore, upon detection of this phenomenon for at least 10 s, the mode
holds a heading that aligns the aircraft’s ground speed on the course,
until the VOR signal is stabilized with a confirmation time of 10 s and
resumes the tracking. During that phase iiVORii label is displayed on
AFCS strip.