King Air C90GTi, Pilot Training Manual

Page: 422 / 557

Figure 16-159. TAWS Buttons
ENHANCED GROUND
PROXIMITY WARNINGS
(PREDICTIVE)
The enhanced features of the TAWS+ system
allows look-ahead protection for terrain and
obstacles that are currently within the flight
path or expected to be in the flight path due to
current descent profile. This is referred to as
Collision Prediction Alerting (CPA). Terrain
for the entire world and obstacles of 250 feet
or more in height are contained in the TAWS+
unit (the obstacle coverage is primarily US
and parts of Canada and Mexico but is gradu-
ally expanding). These functions require GPS1
latitude/longitude, airplane altitude, and the
terrain/airport database.
Note that the database is ACSS specific and
contained within the ground proximity unit lo-
cated in the nose of the aircraft. It is not
mandatory to update this database however it
will help eliminate nuisance alerts by updating
airport and obstacle information. The update
procedure requires access to the aircraft nose
avionics section and must be accomplished by
qualified personnel. After downloading the
database from the ACSS website a compact
flash (CF) card is used to transport data to the
aircraft. A series of lights on the unit will indi-
cate successful or unsuccessful loading.
Terrain display can be selected manually at
any time. Areas of terrain sufficiently close to
the airplane that do not penetrate the terrain
caution or warning envelopes are depicted by
16-89
FOR TRAINING PURPOSES ONLY
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
16
A
VIONICS
Table 16-2. TAWS BUTTONS
Switch/
Annunciator Color Function
FLAP
OVRD
AMBER Pressing the switch disables the TOO LOW FLAPS portion of the TAWS+ Mode 4b alert
boundaries and also desensitizes the Mode 2 envelope. The annunciator illuminates
when the switch is pressed.
G/S
INHIBIT
AMBER Illuminates to indicate the TAWS+ Mode 5 glideslope alert has been inhibited. While
the airplane is on the ground, this switch is used to initiate the TAWS+ system self-
test. The “ACTIVE” annunciator illuminates amber momentarily when pressed and then
extinguishes when released. However the glideslope alerting will remain inhibited al-
though the “ACTIVE” legend will be extinguished. The inhibit function is enabled below
2000ft AGL and disabled at 30ft AGL or after climbing above 2000ft AGL.
TERR
INHIB
GREEN Pressing the switch deselects all enhanced functions of the TAWS+ system. The an-
nunciator illuminates when the switch is pressed.