TAWS Flashcards
TAWS
TERRAIN AVOIDANCE WARNING SYSTEM
3 alerting functions of TAWS?
- Ground Proximity Warning (including altitude awareness callouts and bank angle alerting)
- Terrain (or Obstacle) Awareness and Display (TAD)
- Terrain Clearance Floor (TCF)
The TAWS comprises the following groups of components:
Aircraft sensors and other systems input signals
The Enhanced Ground Proximity Warning Computer
Cockpit Audio Systems (Speakers and Headphones)
Alert Annunciators, Button Lights and Terrain Display Units
How does TAWS extends the Ground Proximity Warning functions of the standard GPWS?
By adding
Terrain (or Obstacle) Awareness and Display (TAD) & Terrain Clearance Floor (TCF) functions and
modulating the Modes 1-6 as required reducing nuisance warnings.
6 Ground proximity warning modes?
MODE 1 -
EXCESSIVE DECENT RATE
CAUTION “SINKRATE”
WARNING “PULL UP!!”
MODE 2 -
EXCESSIVE TERRAIN
CLOSURE RATE
CAUTION “TERRAIN..TERRAIN”
WARNING “PULL UP!!”
MODE 3 -
SINK AFTER TAKE-OFF
CAUTION “DON’T SINK”
MODE 4 -
TOO CLOSE TO TERRAIN
CAUTION “TOO LOW- TERRAIN”
CAUTION “TOO LOW-GEAR!”
CAUTION “TO LOW- FLAPS”
MODE 5 -
EXCESSIVE DEVIATION
BELOW GLIDESLOPE
CAUTION “GLIDESLOPE!”
MODE 6 -
EXCESSIVE BANK ANGLE
CAUTION “BANK ANGLE”
ALTITUDE CALL-OUT- ““500””
CAUTION “…FIVE HUNDRED…”
GPWS MODE 1
EXCESSIVE DECENT RATE
CAUTION “SINKRATE”
WARNING “PULL UP!!”
GPWS MODE 2
EXCESSIVE TERRAIN
CLOSURE RATE
CAUTION “TERRAIN..TERRAIN”
WARNING “PULL UP!!”
GPWS MODE 3
SINK AFTER TAKE-OFF
CAUTION “DON’T SINK”
GPWS MODE 4
TOO CLOSE TO TERRAIN
CAUTION “TOO LOW- TERRAIN”
CAUTION “TOO LOW-GEAR!”
CAUTION “TO LOW- FLAPS”
GPWS MODE 5
EXCESSIVE DEVIATION
BELOW GLIDESLOPE
CAUTION “GLIDESLOPE!”
GPWS MODE 6
EXCESSIVE BANK ANGLE
CAUTION “BANK ANGLE”
ALTITUDE CALL-OUT- ““500””
CAUTION “…FIVE HUNDRED…”
The “enhanced” functions of the TAWS are
Terrain (or Obstacles) Alerting and Display (TAD)
and the Terrain Clearance Floor (TCF).
TADS
Compute 2 envelops
1 Terrain caution alerts
2 Terrain warning alerts
Terrain Clearance Floor
Terrain Clearance Floor (TCF) function (enabled with TAD) enhances the basic GPWS Modes
by alerting the pilot of descent below a defined “Terrain Clearance Floor” regardless of the aircraft
configuration
TCF is active during take off
Mode 4 protection is not
available, and during cruise and final approach.
When the aircraft penetrates the TCF alert envelope, the aural message “Too Low Terrain”
The aural message is
repeated for each 20% degradation in Radio Altitude from the initial penetration.
TA MODE (Terrain Look-Ahead Alerting)
TERRAIN AWARENESS
CAUTION “Caution Terrain, Caution Terrain”
WARNING “Terrain, Terrain, Pull Up”
TA MODE (Terrain Look-Ahead Alerting)
OBSTACLE AWARENESS
CAUTION “Caution Obstacle, Caution Obstacle”
WARNING “Caution Obstacle, Obstacle, Pull Up”
TCF MODE (Terrain Clearance Floor)
CAUTION “Too Low Terrain”
TAWS computer power supply fault
– All modes inhibited.
– Loss of Radio Altitude Mode 1-6 and TCF are inhibited. Note- TAD will be
available
Loss of Radio Altitude
Mode 1-6 and TCF are inhibited. Note- TAD will be
available
Loss of position data
– Terrain awareness functions, TCF and Mode 6 altitude callout inhibited. FAULT
light illuminated.
Test
Perform a system self test on the ground prior to the first flight of the day to verify proper operation
of the TAWS.
Fault light
Fault light to be EXTINGUISHED before every take-off unless the applicable MEL has been
invoked.
