Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Situational Awareness
Inflight Event / Encounter CFTT / CFIT
Flight Crew Took Evasive Action
Aircraft; Airspace Structure
The Captain was Pilot Flying and First Officer was Pilot Monitoring. Descending we were at our previously assigned altitude of 4;300 feet approximately 15 miles southeast of the field in daytime VMC conditions with unlimited visibility; where we notified Approach Control that we had the field in sight. We were given clearance for the Visual Approach. The crew had thoroughly discussed terrain around the airport and had briefed the approach plate emphasizing the terrain with the highest point of the ridge that we would be flying over being 2;381 feet and the night obstacle on the opposite side of the approach being 2;855 feet which we would not have to fly over; but is approximately 5 miles northeast of the airport and final approach course. The Captain set 3;400 feet and began a very shallow descent towards the waypoint where we would intercept the glideslope at 3;400 feet while articulating the reason was to not cause any abrupt descents in order to cause the EGPWS to set off a warning. After reaching 3;400 feet as we were approximately directly over the top of the last ridge we would cross in straight and level flight; the Terrain Warning was set off with 'Terrain...Terrain...Pull-up.'  Immediately; the Captain began a slight climb of maybe 200 feet which quickly silenced the warning. We were quickly over the ridge and the Captain descended back to 3;400 feet where he intercepted the final approach course and began his descent on the glideslope. We landed without incident. I would assume that the abruptness of the rising terrain which we were flying over set off the EGPWS warning even though we were over 1;000 feet above the highest point of the ridge. The Captain immediately climbed and the warning was silenced within a couple of seconds. It would seem that an altitude greater than 3;400 feet while crossing the ridge is necessary to suppress the EGPWS warning system. Perhaps the 3;900 feet altitude of the procedure turn would be sufficient even in VMC conditions.
An Air Carrier First Officer descending on a Visual Approach reported receiving a GPWS alert even though in their present position they were at an appropriate altitude to avoid terrain.