Section 8 Terrain Awareness Warning System
8-18
IDU-450 EFIS Software Version 8.0H (Rotorcraft)
1
st
Ed Nov 2018
4)
GPWS Mode 5
is inhibited below 200’ AGL. This form of automatic
inhibit remains active until the aircraft climbs above 1000’ AGL and
prevents nuisance alarms on missed approach when glideslope
receiver detects glideslope sidelobes.
5)
FLTA function
is automatically inhibited when indicated airspeed or
groundspeed is below the HTAWS FLTA inhibit speed.
8.11.1. TAWS Automatic Inhibit Functions (Abnormal Operation)
The following automatic inhibit functions occur during the specified
abnormal operations:
1)
Autorotation detection
: When the low torque sensor is active, an
Enhanced HTAWS enters autorotation mode. In this mode:
a) FLTA is inhibited;
b) GPWS Mode 1 is inhibited;
c) GPWS Mode 2 is inhibited; and
d) GPWS Mode 4 uses a modified envelope (see § 8.7).
2)
System Sensor/Database Failures
Modes for system sensor failure results.
Table 8-13: TAWS Automatic Inhibit Functions
Sen
sor
Para
me
ters
Los
t
Te
rra
in
D
is
p
lace
d
FLTA
GPWS Mode
1 2 3 4 5
GPS/S
BAS (H)
AC P
os
iti
on
Inhibit
Inhibit
TD
Te
rrain
Elev.
Inhibit
Inhibit