Air carrier crew reported receiving a terrain alert from ATC after performing a missed approach due to wind shear; and losing situational awareness while flying a visual traffic pattern. The Captain readjusted the flight path; then returned for a stabilized approach and landing.
Synopsis
Air carrier crew reported receiving a terrain alert from ATC after performing a missed approach due to wind shear; and losing situational awareness while flying a visual traffic pattern. The Captain readjusted the flight path; then returned for a stabilized approach and landing.
Narrative
While flying the approach into STL Runway 11 we received wind shear roughly 400 feet above touchdown. The wind shear resulted in a -15 knot loss resulting in the CA (PF) to initiate a Go around procedure. Upon calling go around (GA) the airspeed quickly returned to normal causing us to not follow normal wind shear escape procedures and instead use normal GA procedures. It was my first GA procedure as PM; so I believe it didn't go great but remained within standards for our GA criteria. We advised Tower; and Tower offered we could either stay with him or proceed onto departure to be brought back around for the approach. Captain opted to stay with Tower so I relayed that information on. He asked us to descend and maintain 2000 feet which we were already above at the time. So as we leveled and began our decent back down we were at flaps 2 and 180 knots. Tower immediately gave us a turn to crosswind followed by a downwind turn as soon as we were wings level. This resulted in us having the aircraft back in a clean configuration on downwind with roughly 2-3 miles between us and the runway. We ran the after takeoff checklist and immediately began rebuilding the approach to fly back into STL. Roughly 30 seconds to a minute later we were instructed by Tower to begin our base turn. The Captain realized we were still too close to the runway and opted to ask for a few more miles before turning. I requested and was approved by Tower. Once we were a little beyond abeam the F.A.F. the CA turned base and began a decent to 1000 feet AGL as it was a visual approach back into STL. At the same time we also realized the we had a strong tailwind that has been pushing us away from the airport; resulting in us being roughly 8 miles out from the airport descending and reaching 1600 feet MSL or 1000 feet AGL. This resulted in the Tower advising us of a terrain alert and then clearing us to land Runway 11. The Captain; continuing his turn onto final; adjusted the altitude to 1300 feet AGL and set a FLCH up to that altitude. With the close proximity to the Final for the runway; we ended up overshooting the approach course but were able to readjust and rejoin prior the F.A.F for the ILS. The Captain armed the approach and was able to be stable for the remainder of the approach into landing. At roughly 400 AGL we again entered the area of wind shear and had a -10/+10 knot change in airspeed but were able to correct and continue in. However; during this gain the Captain inadvertently bumped the power levers past toga resulting in autothrottles (A/T) disconnection. He quickly corrected the throttles and was stable. We decided to continue and landed in STL with no further issue. Suggestions: The correct decision would have been to proceed onto departure instead of staying with Tower. Having to deal with reconfiguring the aircraft as well as fly a pattern resulted in us not being able to properly divide our attention. It also led to us feeling rushed and slightly uncomfortable; but not unsafe; with the 2nd approach into landing. This issue could be resolved by just continuing onto departure to then be brought back around on a normal/stable approach to landing
Second reporter narrative
During approach into STL Runway 11; around 400 ft; got -10kts for extended period; perhaps 3-4 seconds. I called go around (GA). The airspeed quickly returned to positive performance so I chose not to do the windshear escape. The GA went okay; not perfect but within standards. It was my FOs first GA as PM; so I had to help him through a few of the steps. I had the autopilot and autothrottles off at this point.Tower offered to not send to Departure; and keep us in the pattern. I've never been offered this suggestion before and I accepted. I should have declined this clearance. He instructed us to descend to 2000 ft; as we had already climbed through 2000 ft. As we leveled off; 180 and flaps 2; he instructed us to turn crosswind; and then immediately turn downwind. So we had a 1500 ft. AGL pattern at about 2 miles instead of our normal 3000 ish and 5 miles. Passing abeam the runway; we went flaps up; autopilot and autothrottles on; 210kts and clean; after take off checklist.Before I knew it; we were instructed to turn base. I had my FO ask to extend a few miles which was approved. Not realizing how far the winds had pushed us from the runway; I turned final around 6 miles; set 1000 agl (1600 ft.) and FLCH. This was my big mistake. I mistakenly assumed we were closer to the runway than we were. Leveling at 1600 ft; we received a low altitude alert from ATC; but he said you are still cleared to land; and no warning to climb. I initiated a climb back to 1200-1300 above field. During this time; we checked the approach chart; and only one obstacle at <100 ft. above field; so no issues with terrain. I quickly turned to intercept final. At this point; I overshot final due to a tailwind and the very close base leg. A few moments later; I intercepted the path and final. We met stabilized approach criteria after getting on final.At the 400 ft. mark again; I got -10kts again and quickly recovered; but inadvertantly pushed the throttles into MAX and the system disconnected the auto throttles (Ats). Winds quickly switched to headwind and with ATs off; I went +14kts briefly before recovering to within +10kts.I discussed with my FO; we agreed to continue and land. From there we landed and parked without further incident.Suggestions: I believe I made the right decision to go around on the first approach. My FO had never done a PM go around so I was distracted helping him remember the steps. I had autopilot off during the approach and GA; and I didn't get the autopilot (AP) on until crosswind turn. This set me up to be distracted and behind the airplane for the second approach. After the distraction of the GA; I allowed ATC to rush us into a tight pattern. I should've asked for an even longer downwind and gotten my bearings instead of rushing back to the runway. I knew we had enough gas but I allowed myself to be rushed anyway. Once I made the turn and realized I was low and going across final; I fought to recover the approach and not go around again. In the future; if I find myself in a position to be rushed by ATC; I will stand my ground and not be rushed. And if I need to go around a second time; I will.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.