BendixKing KFC 500 User Manual

Page 16

engages Glideslope Arm (GS ARM),
Capture and Track (GS) sequences
during ILS front course approaches.
The localizer must be captured in
order for glideslope to ARM or cou-
ple. Glideslope coupling is inhibited
during back course procedures.

Any horizontal tracking mode

may be employed during Approach
Arm phases and will cancel automat-
ically upon initiation of Approach
Capture and Track. Any vertical
mode may be used prior to glides-
lope capture or track and will auto-
matically cancel upon initiation of
glideslope capture. Activation of
Approach Capture will automatically
incorporate the default maximum
commanded bank angle, 20°, for
optimum comfort and performance.

A flashing APR lamp indicates

the loss of a sensor required to cap-
ture or track the selected nav (e.g.
invalid NAV, invalid selected course)
and continues until a second push of
the APR pushbutton (pilot acknowl-
edgement of mode loss). The APR
pushbutton also deactivates the
approach and approach arm modes.

When flying inbound on a
Backcourse Approach, the selected
course should be in the opposite
direction of the helicopter's heading.

the Approach mode engages in
either Approach Arm or Capture,
depending on the aircraft’s closure
rate and proximity to the selected
course. The flight director may initi-
ate turn commands before the
course deviation indicator displays
movement. Selecting the Approach
mode after the aircraft has already
passed the point at which Approach
Capture normally would begin may
result initially in course overshoot
due to the flight director’s roll com-
mand limits. If APR mode is called
for by the APR pushbutton and
course needle deflection exceeds the
capture requirements of the
approach mode (greater than 50%
full scale needle deviation),
Approach ARM is activated and a
compatible lateral mode may be
used to intercept the desired course.

The KFC 500 discriminates auto-

matically between front course and
back course approaches, and VOR,
LNAV, and MLS procedures. While
the KFC 500 uses this information to
determine the type of navaid
involved, front course/back course
selections are determined by the rel-
ative angle between the aircraft’s
heading and the course selected on
the EHSI. Intercept angles between
0° and 105° cause the KFC 500 to
select the ILS front course. Angles
between 106° and 180° cause the
flight director to command back
course interception and tracking.

It is essential that the course

selector arrow on the navigation dis-
play always be aligned with the ILS
front course. Failure to align the
course arrow properly may result in
erroneous front course/back course
selection by the KFC 500.

The flight director automatically

TST

BRT

1
2

SYNC

REF

DIR

A
V

A
R
C

H
S

ADF 2

CRS

179

12.6

360°