GPWS

Question 1

What are the five basic modes of the GPWS?

Answer 1

1. Excessive rate of descent (Mode 1)
2. Excessive terrain closure rate (Mode 2)
3. Altitude loss after takeoff or go-around (Mode 3)
4. Terrain clearance not sufficient, if not in landing configuration (Mode 4)
5. Excessive descent below the glide slope (Mode 5)

Question 2

What is Mode 1 of the GPWS?

Answer 2

Excessive rate of descent

Question 3

What is Mode 2 of the GPWS?

Answer 3

Excessive terrain closure rate

Question 4

What is Mode 3 of the GPWS?

Answer 4

Altitude loss after takeoff or go-around

Question 5

What is Mode 4 of the GPWS?

Answer 5

Terrain clearance not sufficient, if not in landing configuration

Question 6

What is Mode 5 of the GPWS?

Answer 6

Excessive descent below the glide slope

Question 7

What is a predictive GPWS function?

Answer 7

A predictive GPWS function is based on a GPWS database to display terrain inform
EGPWS has look ahead function

Question 8

Who provides the predictive GPWS function?

Answer 8

It can be provided by Honeywell through Enhanced GPWS (EGPWS).

Question 9

Which altitude does GPWS use ?

Answer 9

GEometric altitude

Question 10

How does GPWS computes the geometric altitude of the aircraft

Answer 10

• Pressure altitude
• Radio altitude
• Temperature
• Barometric references
• GPS altitude for predictive GPWS

Question 11

What is the caution & warning for GPWS MODE 1 ?

Answer 11

CAUTION-SINK RATE, SINK RATE
WARNING- PULL UP

Question 12

What is the caution & warning for GPWS MODE 2 ?

Answer 12

CAUTION-TERRAIN TERRAIN
WARNING - TERRAIN PULL UP PULL UP

Question 13

What is the caution & warning for GPWS MODE 3 ?

Answer 13

ONLY CAUTION
“DON’T SINK, DON’T SINK”

Question 14

What is the caution & warning for GPWS MODE 4 ?

Answer 14

ONLY CAUTION
TOO LOW
GEAR”
“TOO LOW
TERRAIN”
“TOO LOW
FLAPS

Question 15

What is the caution & warning for GPWS MODE 5 ?

Answer 15

ONLY CAUTION “GLIDESLOPE’”

Question 16

Difference between GPWS & EGPWS ?

Answer 16

GPWS - is limited to look down functionality
EGPWS - has look ahead functionality because of the terrai ndatabase provided by honeywell

In EGPWS , if the aicraft Terrain awareness Display envelope conflicts with terrain database then warning or caution triggers

CAUTION - 60 seconds to impact
warnign - 30 seconds to impact

Question 17

IF EGPWS is active, which mode of Basic GWPS is inhibited ?

Answer 17

MODE 2 - excessive terrain closure of GPWS is inhibited

Question 18

Which provides terrain display Gpws or Egpws ?

Answer 18

EGPWS provides terrain display

Question 19

If EGPWS warning tirggers what is shown on ND ?

Answer 19

Automatic terrain display

Solid red / yellow areas

TERR AHEAD/ OBST AHEAD

Question 20

If EGPWS warning tirggers what is shown AS LOCAL WARNING ?

Answer 20

On each pilot’s instrument
panel, the pushbutton light
comes on.

Question 21

What does Geometric Altitude function can protect against

Answer 21

Some BARO setting errors,

Question 22

For TAD and TCF how is lateral positon obtained

Answer 22

The TAD and TCF functions operate with the use of the pure lateral GPS position. The
FMS1 position provides the backup

Question 23

WHat happens to EGPWS is FMGC dietects low accuracy

Answer 23

the FMGC detects low-navigation accuracy, then the enhanced modes of the EGPWS are
automatically deactivated.
( some aircraft the pilot puts the TERR pb to OFF)

The 5 GPWS modes remain active

Question 24

WHat are the different enevelope the EGPWS uses to trigger warning

Answer 24

TAD –> envelope around the airtcraft to trigger caution (60 seconds) and warning (30 seconds)

TCF –> terrain clearance envelope around airport . This gives enhanced GPWS MODE 4 warnign when there is terrai nclosure when not in landing configuration and when the aircraft descneds belwo the protected envelope
TCF also protects against an attempt to land when there is no airfield ( or no airfield in the database)

RCF –> Table top runways
Runway Field Clearance Floor (RFCF) provides protection envelope for runways that are at an elevation that is significantly more than the surrounding terrain.
The envelope is a circular band that starts within a specific distance of 5 nm from the runway.

If the aircraft descends below this protection envelope, the “TOO LOW TERRAIN” aural and visual
alerts are triggered

Question 25

WHat does **SYS Pb** on GPWS panel do , when put to OFF ? ANd what does it mean when FAULT light illuminates ?

Answer 25

OFF - All basic GPWS alerts (mode 1 to 5) are inhibited FAULT - Basic GPWS modes 1 to 5 are failed. **The NAV GPWS FAULT alert is triggered**. Note: If ILS 1 fails, only GPWS mode 5 is lost. The NAV GPWS FAULT alert does not trigger. On ground, the GPWS FAULT light turns on. In flight, the GPWS FAULT light does not turn on, while GPWS modes 1 to 4 are operative.

Question 26

WHat does **TERR Pb** on GPWS panel do , when put to OFF ? ANd what does it mean when FAULT light illuminates ?

Answer 26

OFF - The predictive modes of the GPWS are inhibited. The basic GPWS modes 1 to 5 are operative. The inhibition of predictive GPWS modes may lead to nuisance alerts of the basic GPWS mode 2 alerts on approaches with sudden radio altitude changes (e.g. cliff on the approach path FAULT -Predictive GPWS modes are failed. **The NAV GPWS TERR DET FAULT alert is triggered.** The terrain is not shown on the ND. Note: The basic GPWS modes 1 to 5 are still operative when the SYS pb-sw OFF light or the SYS pb-sw FAULT light are not illuminated.

Question 27

what does G/S mode pn sw do when put to OFF ?

Answer 27

ON - Glide slope mode (mode 5) is active. OFF - Glide slope mode (mode 5) is inhibited

Question 28

what does FLAP mode pn sw do when put to OFF ?

Answer 28

OFF- Flap mode ("TOO LOW FLAPS" mode 4) is inhibited (to avoid nuisance warning in the case of landing with flaps setting reduced). ON - Flap mode ("TOO LOW FLAPS" mode 4) is active

Question 29

what does LDG FLAP 3 pb-sw do when put to ON?

Answer 29

OFF - There is no OFF Position ON - Flap mode is inhibited when CONF 3 is selected (to avoid nuisance warning in the case of landing in CONF 3). LDG MEMO displays FLAPS...3 instead of FLAPS...FULL

Question 30

How to do GPWS test ?

Answer 30

On the ground only, the flight crew presses PULLup/gpws (above pfd nd brightness) pb to test the GPWS.

Question 31

WHat to do when MODE 5 alert GLIDE SLOPE is heard , and you want to silcence it ?

Answer 31

If the flight crew briefly presses the PULL UP – GPWS pb when mode 5 alert is heard, the GPWS light goes off and the aural alert stops

Question 32

How to Identify the difference between the terrain and the weather display

Answer 32

To be able to identify the difference between the terrain and the weather display, the terrain display goes from the center outward to both sides of the ND

Question 33

WHen terrai non ND Pressed . when will the terrain display appear on ND (at what height of terrain) ?

Answer 33

The terrain and obstacles image appears on the ND if: - The aircraft is within 2 000 ft above the terrain

Question 34

When does TERR ON ND pb display terrain on ND ?

Answer 34

The terrain appears on the ND if all of the following apply: - TERR ON ND pb-sw is set to ON - TERR FAULT light is not on - TERR STBY ECAM memo does not appear - The FMGS navigation accuracy is high.

Question 35

What ECAM memo TERR STBY means ?

Answer 35

Airborne TERR STBY memo appears in green when the aircraft position accuracy (computed by the EGPWS) is not sufficient to allow the enhanced TCF and TAD modes to operate. These modes are not available until the TERR STBY memo disappears. If selected, the terrain data display on ND is automatically deselected when the TERR STBY memo is triggered