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The GPWS warns the crew in case of:

1 – deviation above or below the selected altitude
2 – deviation below the selected altitude
3 – unsafe terrain clearance with flaps not in landing configuration
4 – unsafe terrain clearance with landing gear not down.

The combination that regroups all of the correct statements is:

  • A
    2, 3.
  • B
    2, 3, 4.
  • C
    1, 4.
  • D
    3, 4.

The Ground Proximity Warning System is now a required equipment that improves safety and provides numerous protections that prevent Controlled Flight Into Terrain (CFIT). It uses a lot of data coming from the Air Data Computer (ADC) such as the airspeed (CAS), the vertical speed, and baro altitude (which is sometimes not included as a valid answer in the official examination), radio altitude (height), glideslope deviation, and flaps and landing gear position. The GPWS operating range is from the ground up to 2500 ft RA and is required on jet or turboprop aircraft of more than 5 700 kg or with more than 9 seats. It must provide a distinctive aural warning and visible signal to the flight crew in case of:

Mode Meaning Initial Aural Alert Second Aural Warning
Mode 1 Excessive descent rate “SINK RATE, SINK RATE” “WHOOP WHOOP PULL UP” (twice)
Mode 2 Excessive terrain closure rate “TERRAIN TERRAIN” “WHOOP WHOOP PULL UP” (continuously until the radio altitude stopped reducing and an increase of 300’ baro is measured)
Mode 3 Altitude loss after take-off or go-around "DON`T SINK" (twice) NONE
Mode 4 Unsafe terrain clearance with flaps and landing gear NOT in landing configuration “TOO LOW GEAR,” “TOO LOW FLAPS,” “TOO LOW TERRAIN” NONE
Mode 5 Downward glideslope deviation “GLIDESLOPE, GLIDESLOPE” at half volume “GLIDESLOPE, GLIDESLOPE” at full volume
Mode 6a (not required by OPS-1) When passing the decision height “MINIMUMS, MINIMUMS” NONE
Mode 6b (not required by OPS-1) Excessive bank angle “BANK ANGLE, BANK ANGLE” NONE
Mode 7 (not required by OPS-1) When expecting or already encountering wind shear “CAUTION WINDSHEAR” “WINDSHEAR, WIDSHEAR”

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