Air carrier flight crew reported receiving a low altitude alert during arrival as they descended on downwind in the vicinity of terrain.
Synopsis
Air carrier flight crew reported receiving a low altitude alert during arrival as they descended on downwind in the vicinity of terrain.
Narrative
During our arrival into ZZZ; I had planned on landing on Runway XXL. I had briefed the ILS approach since the winds were calm and that runway provided more of a straight-in approach. I had also briefed a runway change as a potential threat and that the mitigation strategy was for the FO (First Officer) to change the approach in the box and brief the high points of the appropriate approach. When we were able to get the ATIS information; we learned that the runway in use was Runway XYR. We got the runway change early enough that I was able to change the approach in the box and brief the approach. I failed; however to recognize the proximity of the terrain in relation to flying an approach using a right hand pattern. The Controller cleared us down to X;000 feet and; after clear of crossing traffic; down to maintain Y;000 feet while we were still approximately 20 miles north east of the field. We were here given vectors to set us up for a right downwind to [Runway] XYR. When asked if we had the field in sight; we said yes and were cleared for the visual approach to [Runway] XYR when we were approximately 10 miles east of the field. Then; during our downwind; approximately abeam the field; we were asked if we wanted a 5 mile or 10 mile final for planning purposes. I was already partially configured; so I opted for the 5 miles final due to the terrain that I now realized was right off the nose. It appeared to me that a 10 mile base turn would put me uncomfortably close to the terrain. I then got a bit task saturated trying to figure out what altitude I could descend to based on the intermediate fixes inside of ZZZZZ. Of course; I'm now realizing that ZZZZZ is greater that 5 miles from the runway. So I set a lower altitude; I think it was Z;ZZZ [ft]. Again; I was visual and only using the RNAV approach for lateral guidance. As I started my base turn and descent; we received an EGPWS (Enhanced Ground Proximity Warning System) terrain call followed by TERRAIN; PULL UP. I disconnected the auto pilot; added power; and started to pull up. As all of this was happening; the Tower Controller called us to tell us to check our altitude and advised us that the minimum vectoring altitude was Y;100 feet (I think). Because I was visually clearing myself from terrain; I didn't make any aggressive maneuvers. And within a few seconds; the EGPWS alerts went away. I was on glide path and on speed; maybe a little fast; but made an otherwise uneventful; stable approach to a landing. The primary cause of this event was starting my descent too early. I was unfamiliar with the airfield as it was my first time there; and I failed to recognize the scale of the terrain in the vicinity of the airfield. I was also a bit task saturated trying to get configured while figuring out how [to] make a 5 mile final work given the terrain and unfamiliarity of the approach. If I were to do this approach again; I would have asked for the entire RNAV approach starting from either ZZZZZ1 (for a right downwind) or ZZZZZ2 (for a left downwind). I'm honestly not sure how I could have flown that approach visually to a 5 or even 10 mile final and avoided the EGPWS warning and be stable. Especially starting from X;000 feet when the highest terrain in that sector is [close to that]. A left downwind would have worked much better. Or only get cleared down to Y;800 feet and start from a 15 mile final. Something in the company pages detailing the threat of the terrain during a right downwind approach to [Runway] XYR or maybe an increase of the airport risk level from a 2 would be helpful.
Second reporter narrative
Descending into ZZZ; we were cleared for the visual [Runway] XYR and cleared to descend to X;000ft. We entered a right downwind. Tower asked if we planned to join a 5 mile or 10 mile final and we said a 5 mile final. In hindsight; we set ourselves up for difficulty. There is high terrain south west of the approach course that we had to avoid. We could have stayed at the MSA (Y;100 ft) to overfly it and intercept a long final; or begin the descent and make an early base leg for a short approach. We did not do a good job of briefing this as neither of us had been to this airport before. The Captain chose to make the early turn for the short approach. I made a comment about the terrain seeming a bit close and within a minute after that; the EGPWS (Enhanced Ground Proximity Warning System) 'terrain pull up' aural sounded and Tower alerted us of our proximity to the mountain. The Captain disconnected the autopilot; stopped the descent rate; and hand flew us to the final approach course where we completed the approach without issue. The main causes were unfamiliarity with the airport and inadequate briefing regarding the terrain. Approaching an airport with nearby terrain; where neither pilot had been before; it would have been smarter to request an instrument approach for added safety. Visual approaches are difficult to replicate in the simulator; but a larger emphasis on performing them near terrain would be beneficial to new hires and new captains.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.