A319
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness; Workload
ATC Issue All Types; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Aircraft; Human Factors
After being vectored off the SILCN 4 arrival into San Jose; we were given direct to the fix GGUGL and instructed to descend via the SILCN 4 for Runway 12R. The next Controller cleared us to descend to 5;100 ft. and shortly after reaching that altitude; we responded to an EPGWS warning 'Terrain Terrain Pull Up'. I told ATC that we were responding to a terrain warning and after we'd climbed about 1;500 ft.; we were out of the clouds & could see we were above any possible obstacles. Out of an abundance of caution & because it took a while to put the aircraft back into a more normal posture; we climbed to 10;000 ft. before getting vectors for the approach. Task saturation was definitely a factor in why this happened. The Captain and I were so inundated with tasks that we were unable to detect ATCs mistake.Mistakes happen. Updating the old 319 EPGWS systems will detect conflicts sooner and more accurately.
A319 First Officer reported that an erroneous GPWS warning during initial descent resulted in an altitude deviation.