A321
Human-Machine Interface; Training / Qualification; Situational Awareness
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors; Software and Automation
We were descending on the [arrival] from the northeast for an approach to [Runway] XXR in VMC. We had briefed the extensive military training and the towers in the airport area. We were on a vector of approx 260 and were cleared for the visual. I selected 2800 ft. in the FCU (Flight Control Unit) altimeter (the FAF/ALAMO altitude); and we began to descend and start the big left hand turn (120+ degrees) to final. The runway was actually behind the Captain's head and while I was looking outside and dialing in intercept headings; I noticed we were below 2800 ft. I remarked that 2200 ft. was in the altimeter; but I didn't know why. (In hindsight; I must have bumped or spun the dial as I reached up to make heading adjustments). About this time we received a GPWS obstacle alert for the tower we had briefed and was in sight. By the time we climbed back up to 2800 ft. we were high (ILS NOTAM'ed OTS) and I couldn't see [the] runway in the climb and then was slow to get speed back. We finished configuring; ran the checklist and briefed a go around if not stable by 500 ft. [Cause includes] Lack of recency of experience -- I sat for a year before Airbus training after the [other make/model] was grounded. I was on that aircraft [for about a year]; but flew 2/3 to 3/4 as the [relief pilot]. Prior to that; I was out on a 4 yr leave (not flying). Lack of time in Airbus - [this month] was my third full month of being qualified on the aircraft. Not yet comfortable with [the] concept of 'flying the FCU' on visual approaches. There is no way to 'chair fly' the approaches in an Airbus. I don't enjoy this feeling. I've looked for a simple computer simulation program for the FCU; FMA; PFD and ND that I could purchase so I could chair fly some of these situations and see what happens as different modes of speed; alt; and nav are selected; but have not found one yet.
A321 First Officer reported descending below minimum altitude on approach and receiving a GPWS obstacle alert. Reporter stated lack of recent experience and practice using the various navigation equipment contributed to the event.