B737 Undifferentiated or Other Model
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 202; Flight Crew Type 557
Workload; Situational Awareness; Distraction; Confusion; Time Pressure
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Flight Crew FLC Overrode Automation
Aircraft; Environment - Non Weather Related
During our approach into PSP we were cleared for the visual so the Captain went direct to the fix JISOP; situating us so that we were on base and would turn to final over that waypoint. Crossing altitude for that fix was 2;900 and we were in VNAV and LNAV. As we approached JISOP we set touchdown elevation as we were altitude protected in the box. As we turning from base to final we heard 'Caution terrain. Caution terrain.' At that point we noticed we were about 2;700 feet. The Captain leveled off; finished turning to final; and once clear of terrain continued the decent and landing with no incident.
During approach we were cleared for the visual approach. We were cleared to the fix JISOP on the RNAV RNP 31L. Crossing altitude was 2;900 MSL or above. We were in VNAV & LNAV. As we approached JISOP we set touchdown elevation as we had altitude protection in the FMC. We were just about to make a 90 degree turn to final from JISOP. The aircraft had lost VNAV and continued a shallow decent below 2;900 feet. As we both noticed about the same time we were at 2;700 feet in the turn to final; 200 feet below JISOP. At the same time we got a terrain warning. We leveled off; made the turn to final and landed without incident. It was day VFR and we knew exactly where we were in relationship to the terrain.
B737 flight crew reported receiving a GPWS terrain warning as they descended below a crossing altitude while in VFR conditions.