4. GPWS

Question 1

TERR

Answer 1

On (lights out):

In addition to the basic GPWS functions, the GPWS has an enhanced function (EGPWS) which provides, based on a worldwide terrain database:

A Terrain Awareness Display (TAD), which predicts the terrain conflict, and displays the terrain on the ND.
A Terrain Clearance Floor (TCF), which improves the low terrain warning during landing.
The EGPWS uses the geometric altitude. The geometric altitude is calculated by means of a specific algorithm that uses the following as inputs: The pressure altitude, GPS altitude, radio altitude, and data from the terrain database.

Note: A number of airports throughout the world have approaches or departures that are not entirely compatible with standard GPWS operation. These airports are identified in the envelope modulation database, in such a way that, when the GPWS recognizes such an airport, it modifies the profile to avoid nuisance warnings.

OFF:

Inhibits the Terrain Awareness Display (TAD) and Terrain Clearance Floor.

(TCF) modes does not affect the basic GPWS mode 1 to 5. If OFF is selected the ECAM caution NAV GPWS TERR DET FAULT is displayed.

FAULT Light:

This amber light comes on, along with an ECAM caution, if the TAD or TCF mode fails. The terrain is not shown on the ND. The basic GPWS mode 1 to mode 5 are still operative if the SYS pushbutton OFF or FAULT lights are not illuminated.

Question 2

SYS

Answer 2

On (lights out):

Normal position. The Ground Proximity Warning System (GPWS) generates aural and visual warnings, when one of the following conditions occurs between radio altitudes 30 ft and 2 450 ft.

Mode 1: Excessive rate of descent.
Mode 2: Excessive terrain closure rate.
Mode 3: Altitude loss after takeoff, or go-around.
Mode 4: Unsafe terrain clearance when not in landing configuration.
Mode 5: Too far below glideslope.
OFF:

All basic GPWS alerts (Mode 1 to 5) are inhibited. The OFF light illuminates white.

FAULT Light:

This amber light comes on, along with an ECAM caution, if the basic GPWS mode 1 to 5 malfunctions.

NOTE: If ILS 1 fails, only mode 5 is inhibited. Consequently, the FAULT light does not come on and the GPWS FAULT warning is not triggered.

Question 3

G/S
MODE

Answer 3

On (lights out):

Normal position. Glideslope mode (mode 5) is active.

OFF:

Glideslope mode (mode 5) is inhibited. The OFF light illuminates white.

Question 4

FLAP
MODE

Answer 4

On (lights out):

Normal position. Flap mode (mode 4) is active.

OFF:

Flap mode (“TOO LOW FLAPS” mode 4) is inhibited. (To avoid nuisance warning in case of landing with flaps setting reduced). The OFF light illuminates white.

Question 5

LDG
FLAP 3

Answer 5

On (lights out):

Normal position.

ON:

Flap mode is inhibited when FLAPS CONF 3 is selected (to avoid nuisance warning in case of landing in CONF 3). In this case, LDG MEMO displays “FLAPS … 3” instead of “CONF … FULL”. The ON light illuminates white.