Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Situational Awareness
Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action
Human Factors; Airport
During approach to Runway 9R at PHL; Crew was assigned 4000 ft. altitude and vectors to intercept localizer to Runway 9R. After descending and establishing at 4000 ft. and the assigned vector; ATC instructed us to descend [to] 3000 heading 120 to intercept the localizer. As we descended from 4000 to 3000 around 3200; a GPWS alert of 'TERRAIN' came on. Pilot Flying disconnect AP (Autopilot); seconds after that another GPWS alert 'PULL UP' was received; PF (Pilot Flying) initiated escape maneuver and initiated climbed. Pilot Non-Flying contacted ATC and advised we had a GPWS alert and we were climbing. ATC asked want altitude do we want to level off; PF said 4000 and ATC assigned us 4000. ATC asked if we can continue the approach from that altitude to which PF indicated that yes we can intercept the LOC and GS. PF continued the approach hand flown to intercept the ILS and landed uneventfully.
Vectors ILS 9R; NIGHT/IMC; outside ASOCI on heading 120 approximately 3200 ft. MSL we got a terrain caution message; almost immediately followed by a terrain warning with 'pull up' command. The Captain turned off the autopilot and immediately began a full power climb. At this time we were getting ATC instructions for the approach; which I then was able to tell ATC we were climbing due to terrain warning. At 4000 ft. the warning had gone away; ATC asked if we could accept 4000 ft. Once established at 4000 ft. ATC asked if we were good to shoot the approach. We were given vectors and intercepted the localizer; then the GS at 4000 ft. and had an otherwise uneventful ILS approach and landing.We are unsure why we would have gotten the terrain caution or warning. We were on vectors and well above the obstacles in the area with a normal descent rate.
CRJ-700 Flight Crew reported receiving a Ground Proximity warning on approach to PHL.