12 / 20
The EGPWS may propose the Terrain Look-Ahead Alerting function, this function uses:
  • A
    the same caution and warning envelopes than the mode 2 GPWS (excessive terrain closure rate).
  • B
    a specific radar to detect any high ground in conflict with the flight path of the aircraft.
  • C
    the weather radar to detect any high ground in conflict with the flight path of the aircraft.
  • D
    an electronic map of the world giving ground elevation.
The EGPWS is an ENHANCED GPWS that has its own world terrain database. Therefore, if the aircraft experiences a position computation malfunction and is not accurate anymore, the terrain display will diverge from the real terrain environment around the aircraft position, and it will be erroneously indicated on the pilots’ Navigation Display (ND) (refer to figure). The EGPWS may contain the following additional functions:
  • Terrain Clearance Floor (TCF).
  • Terrain Look Ahead function.
  • Terrain Alerting and Display (TAD).

The simple GPWS cannot detect a rising pick and provide useful and timely alerts since its measurements are based on the RA. However, the TCF function of the EGPWS contains an electronic map with all the obstacles and terrains giving the ground elevation, which means that the system can ‘see’ what obstacles are lying ahead of the aircraft = it has a ‘look-ahead’ capability.
The terrain alerting function of the EGPWS generates a caution, which leaves the pilot with a response time between 40-60 sec, followed by a warning, which leaves the pilot between 20-30 sec to react.
 

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.