Vertical command control, Normal operation – BendixKing KFC 500 User Manual

Page 17

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Normal Operation

Normal Operation

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June 15, 1999

006-18081-0000

006-18081-0000

June 15, 1999

existing roll attitude if greater than 6°.
Roll attitudes of less than six degrees of
bank will cause the Flight Director to
revert to commands for roll-level flight
with heading hold. When heading select
(HDG) mode is engaged, the heading
bug on the EHSI may be re-positioned
to a new heading using the CBT switch.
Moving the CBT switch to the left will
slew the heading bug counterclockwise
while movement to the right will slew the
bug clockwise. The AFCS is designed
with absolute attitude limits and rate lim-
its. During fly through or other modes of
operation , the aircraft attitude/rate must
be less than + or - 45°/15° per second in
roll and + or - 15°/10° per second in pitch and 15° per second in yaw for the
AP mode to remain engaged. If these limits are exceeded the autopilot will
automatically disconnect.

Activating Discrete or Continuous Lateral Command has the following effect
upon command values in flight director operations:

Vertical Command Control

Using the same cyclic switch as
mentioned in the previous para-
graph, vertical commands can be
modified by moving the CBT switch
fore or aft. Operation of the Vertical
Command Control depends on the
flight director mode engaged.

Flight Director Lateral Command Values

Discrete Command

System Response

Roll Attitude Hold

First Click=6°, Subsequent=1° per click

Heading Select

1° Heading Bug novement per click

Continuous Command

Roll Attitude Hold

Roll Rate of 7° per second

Heading Select

16° Heading Bug movement per second

Moving the switch forward adjusts
the helicopter’s pitch attitude down-
ward, while moving it aft (rearward)
adjusts the attitude upward.
Activating Vertical Command has
the following effect on flight director
vertical modes: has no effect on ALT

ARM (altitude preselect arm), ALTC
(altitude capture), GS (glideslope),
GA (go around), overspeed protec-
tion (nose down or increasing air-
speed), and autolevel. To use
Vertical Command Control when
these modes are engaged, first des-
elect the mode. Vertical Command
will trim or modify the reference for
PIT (pitch attitude hold), ALT (alti-
tude hold), VS (vertical speed hold),
IAS (indicated airspeed hold) and
overspeed protection (nose up or
decreasing airspeed). Attitude Hold,
Altitude Hold, Indicated Airspeed
Hold, and Vertical Speed Hold will
remain coupled throughout Vertical
Command (CBT) operation.

CBT

Flight Director Vertical Command Values

Discrete Command

System Response

Pitch Attitude

0.5° per click

Altitude Hold

10 feet per click

Indicated Airspeed Hold

1 Knot per Click

Vertical Speed Hold

100 feet per minute per click

Continuous Command

Pitch Attitude

Maintains constant. acceleration profile

of 0.1 g or 2° per second whichever is

greater until released and then holds the

attitude at release

Altitude Hold

50 feet per second until release

Indicated Airspeed Hold

5 knots per second until release

Vertical Speed Hold

300 feet per minute per second until

release

AFCS DISC

FD OFF

CYCLIC GRIP SWITCHES

CBT

FTR

Activating Discrete or Continuous Vertical command Control has the following
effect upon command values in flight director operations:

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