GPWS
From Rise: The Vieneo Province
The GPWS (Ground Proximity Warning System) is a safety device factory standard in aircraft and aerospace vehicles to alert the flight crew when one of the following thresholds are exceeded.
Mode 1 - Excessive Decent Rate
Has two (2) boundaries and is independent of vehicle configuration. Penetration of the first boundary generates the repeated aural alert of "sink rate". Penetrating the second boundary causes the repeated aural warning of "WOOP WOOP, pull up", until the rte of decent has been corrected.