Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Time Pressure; Workload; Human-Machine Interface
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Human Factors
Unanticipated GPWS warning on approach requiring crew action. We were flying the freighter (tail); second leg ZZZ-ZZZ1 (1.5 hr delayed at start of day); 5-6 hours into the flight duty period (~XA:00 pm local time). Night IMC w/moderate to heavy rain showers in vicinity. I was Pilot Flying PF (Captain).Clearance was ZZZ...ZZZ1. On the ground at ZZZ we planned and briefed the departure and RNAV (RNP) Rwy XX from the ZZZZZ1 transition. De-iced; taxied; departed; climbed to cruise at FL280.Enroute to ZZZZZ1 at cruise; Center warned of areas of moderate to extreme precipitation from ZZZZZ1 fix to the airport and advised of better weather to the Northeast. After discussing a change to the arrival; we both agreed to request radar vectors to the approach segment from ZZZZZ (IAF). Center agreed to vector us around and down to put us on the published portion of the arrival with the stated intention of joining us to the approach path at ZZZZZ2. FO (First Officer) made the changes in the FMS and we briefed and then ran the Decent Checklist Change Triangles.Radar vectors included a descent and vectors resulting in established on published segment near ZZZZZ2 at 5000 and given approach clearance from center (I had directed PM to reset FMS Cruise Alt to 8;000 feet when we were on vectors). Once established near ZZZZZ2 at 5;000 cleared us for the approach. I engaged LNAV/VNAV and set airport elevation; but was high on the vertical path. I continued to slow to final configuration (gear down; Flaps 40) by ZZZZZ1; stable; but still 1;400 feet above the path in VNAV SPD (vertical navigation speed). After the turn at ZZZZZ1 I set 1;600 feet in the MCP ALT window (FAP 1;600 MSL) and at approximately 2;300 MSL; engaged Vertical Speed down in order to regain the VNAV Path before the FAP. As I approached the path; I reset MCP altitude to airfield elevation and engaged VNAV while pitch mode was in ALT ACQ (altitude acquire); resulting in an unrecognized mode change to V/S (2;100 ft/min) and projected vertical path well before the airport. It was at this point; we received a GPWS 'Caution Terrain' followed shortly by GPWS Warning 'Terrain Fly UP.'  I immediately executed an escape maneuver/go-around; climbing and flying the go-around flight path to ZZZ2 and mistakenly climbed to 5;000 MSL (missed approach alt 3;000 MSL); entering the hold as published. I requested and was given a descent to 3;000 MSL in holding.We then built and briefed the RNAV (RNP) Rwy XX from ZZZ2; ran the Descent Change Triangles; received our approach clearance; and executed the approach to landing uneventfully. The FO and I thoroughly debriefed the events of the flight. I then called the Duty Pilot and DISPATCH to report the incident. I should have requested radar vectors ZZZZZ1 for the best opportunity to acquire the VNAV path. I allowed the Controller to compress and to keep me high on my approach; and reducing my situational awareness. I configured very early; but it still wasn't enough to regain the VNAV path. In the future; I will not allow the ATC Controller to dictate the terms of my energy management and will give myself the Flight Handbook recommended 3 miles per 1;000 descent planning as a minimum starting point.Because we compressed our arrival and ended up high above the VNAV path I attempted to use the Vertical Speed method on LNAV/VNAV Approach rules to regain VNAV path prior to the FAP. Had I cross-checked my FMA after selecting VNAV; I would have noticed the V/S mode and perhaps executed an uneventful go-around. In the future; I will make sure to always verify my FMA mode on the PFD after making a selection on the MCP.Lastly; after fully configuring and still not descending to the path; I might have been able to acquire VNAV path prior to the FAP using Speed Intervention. There was chance we were light enough (low Ref Speed) to accelerate the idle pitch descent to regain the path; ensuring the pitch FMA remained in VNAV and avoiding the unrecognized and inadvertent V/S mode descent that caused the GPWS Warning. Recommend expanding the understanding of VNAV speed during initial and continuing qualification training in the B737.
Escape Maneuver occurred at approximately (time) local time on (date). Flight conditions at the time were night; IMC; rain; light turbulence.Leg 2 of a planned 4 leg day. Leg 1 was delayed 1 hours due to cargo loading. The flight was uneventful. Deiced in ZZZ after aircraft pushback. Filed route was ZZZ...ZZZ1. We planned and briefed the RNAV Rwy XX from ZZZZZ. Cruise was at FL280. PF (pilot flying) MFD was in WX Radar mode due to significant weather in the area. PM (pilot monitoring) was in TERR (terrain) mode with VSD (vertical speed) displayed. Cruise was at dusk. Shortly after starting the descent; ATC notified us that he saw an area of Moderate to Extreme precipitation ahead of us. ATC said it looked clearer to the north and asked if we would like vectors to the north for an approach via ZZZZZ1. We responded yes and he started vectoring us north. PF flew while PM loaded the arrival from ZZZZZ1 (via IAF ZZZZZ1). PM briefed the new approach and called for change triangles; which we accomplished. ATC had us do intermediate level-offs at 8;000 feet; then 7;000 feet. PF asked PM to reset the cruise altitude to provide an accurate flight path. In anticipation of being high on flight path; PF configured early to flaps 40. PM was actively monitoring the VSD and flight path; and requested lower when able from ATC. ATC said he would give us lower in a few miles. He then gave us a short vector prior to ZZZZZ2 with a descent to 6;500 feet. At approx 0.5 miles before ZZZZZ2 at 6;500 feet; ATC cleared us 'to cross ZZZZZ2 at or above 5;000 feet; cleared RNAV Rwy XX at ZZZ1'. When cleared for the approach over ZZZZZ2; PF dialed in field elevation in the MCP and descended towards the flight path. Flight conditions were night; IMC; rain; light turbulence. Approximately 1 mile prior to ZZZZZ3; we were still high on flight path so PF verbalized and set Vertical Speed down and reset MCP to 1;600 feet. PM saw the downward vector on the VSD and monitored it for approaching the flight path. Almost immediately thereafter; we received a 'Caution; Terrain' and the depicted island terrain went yellow on PM's MFD. This was quickly followed by a 'Terrain; Pull up' and the depicted terrain on the MFD went red. PF called for go-around and executed the escape maneuver. After aircraft was climbing; PF asked PM to reset MCP for missed approach altitude of 3;000 feet. PF initially had difficulty verifying the missed approach altitude on the EFB due to turbulence; transition to nighttime; and prioritizing monitoring the aircraft state while performing aircraft cleanup. PF put and verbalized 5;000 feet in the MCP window; thinking 5;000 feet was better in case 3;000 feet was incorrect. PMs intent was to devote more brain cells to performing the aircraft cleanup items and monitoring the safe aircraft state as we climbed. Aircraft was cleaned up; leveled at 5;000 feet and continued to holding at ZZZ2. We then queried ATC for a descent to 3;000 feet; setup the RNAV Rwy XX from ZZZ2. Approach was briefed by Captain; flown; and landed uneventfully. Once the aircraft reached parking and shutdown at ZZZ1; Captain and FO debriefed the events. Captain called and briefed Duty Officer; who approved continuing to the remaining 2 destinations. Captain also called and spoke with Dispatch. The remaining flights to were flown with minimal changes. Post flight; the Captain called Quality Assurance to see what they could tell us; so that we could learn further from this experience.Stay on the magenta line; and if vectored off; get back on it as early as possible. Even though the controller had plans to vector us back onto the RNP approach; a better outcome likely would have resulted if we started at the IAP. This way we would have been able to descend on a normal flight path; with adequate time and pacing; vs. having to stay higher due to the controllers higher vectoring altitudes. Request the IAP next time.At nighttime in IMC; I need to have a faster response timecalling for the escape maneuver/go-around. I should clarify this maneuver more; particularly the triggers. I should have been the first to call for it since the Captain was the PF. Instead of trying to salvage a bad or difficult approach; make the decision to go-around earlier. Memorize the missed approach altitude prior to each approach; or ensure my EFB chart is not zoomed-in so far that I cannot see it without a quick glance.Clarify various 'what-if scenarios' on RNP approaches; Escape Maneuvers; Go-Arounds. If I haven't flown as much recently; spend extra time clarifying. Communicate with Center that 6;500 feet at ZZZZZ2 creates a very difficult approach to accomplish. Recommend to them that vectoring to the IAF is likely a better option.
B737-700 flight crew reported executing an escape maneuver due to a CFIT event resulting from a compressed approach clearance. Crew completed subsequent approach in an uneventful landing.