This type of RA occurs when at the closest point of approach (CPA) the present vertical speed results in a safe altitude separation from the threat airplane. When this happens, the aural advisory comes on.
These are the aural messages for the preventive action RA:
· MONITOR VERTICAL SPEED
· MAINTAIN VERTICAL SPEED, MAINTAIN
· MAINTAIN VERTICAL SPEED, CROSSSING MAINTAIN.
The preventive action RA messages tell the flight crew to do these things:
· Maintain the flight path
· Do not fly into the area of RA pitch symbol on the ADI
· Maintain the vertical speed rate.