Date: 201712
Local time of day: 1801-2400
Location: ZZZ.Tower, US
Flight conditions: IMC
Weather elements / visibility: 3
Light: Night
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Human-Machine Interface; Communication Breakdown; Workload
Second reporter function: Pilot Flying; Captain
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Aircraft Terrain Warning; Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Executed Go Around / Missed Approach; Flight Crew Became Reoriented
Contributing factors: Weather; Procedure; Human Factors
Primary problem: Human Factors

Narrative: While on arrival an hour prior to landing; I (PM) retrieved the ATIS and the Performance W&B for a south landing. Coming from the west; I figured 20R was the obvious choice of runway and with the current weather conditions on the field; I assumed we would be doing the ILS to 20R. As nearly the entire flight was a sterile cockpit except a few conversations about turbulence and weather; I had set myself up for the ILS to 20R and waited for the Captain to brief it. As we approached the top of descent; the Captain stated that he was planning the RNP Z to 20L and told me that he wanted me to request that with approach. He briefed the approach; we discussed a few details about RNP value to input and accomplished the descent checklist. The Captain; for some reason; seemed adamant about landing on the left side.When I checked in with Approach; I gave him our request. Their reply was; 'You can expect 20L. I'll have to see about the RNP approach.' Figuring we would not get the RNP approach; I went ahead and tuned in the ILS frequency on my side to 20L. As we entered the downwind; Approach said they were unable the RNP approach; plan the ILS. The Captain then briefed the ILS approach to 20L. As we were being vectored; we were going in and out of heavy rain and turbulence. As we were getting close to turning base leg; Approach came on the frequency and stated that the braking action for Runway 20L was reported poor by a 737. Approach then told another aircraft to plan runway 20R. The Captain was adamant to me he still wanted Runway 20L. Approach called us on our base leg to 20L and restated the braking action for 20L was poor and to turn to a heading and intercept the LOC to 20R and gave us the frequency. The Captain went heads down in the FMC to program the approach. At this point; I already had the frequency in standby on my side so I switched the frequency; then turned to my iPad to pull up the approach. As this was all taking place; we were cleared to 2000 ft; cleared for the ILS; and handed off to Tower. As we continued; the Captain was calling for flaps and trying to quickly configure the airplane while I was contacting Tower. I noticed the Captain had LNAV engaged on the panel; so I was assuming he was intercepting the LOC course with that. The next thing I knew; we blew through the LOC and the Captain had clicked off the autopilot and was rejoining. At this same time; Tower stated that he showed us left of course. I stated that we were correcting. The Captain then reengaged the autopilot and was still configuring the airplane. While all this was going on; I'm still trying to reset the baro for the minimums and the next thing I know; the Captain turned off the autopilot again. While I was looking to try to double check his frequency; Tower said they were showing us off course and I believed he asked us if we wanted to go around.The Captain stated to me; 'I've got it now;' so I assumed that meant he had the LOC and the GS captured. So while I'm looking at my PFD; I'm relaying to ATC that we got it. By the time I was done with my transmission to ATC; the Captain was diving the aircraft to the ground I saw at least a 1500 fpm descent all at the same time my LOC guidance was gone. I heard sink rate; and I told the Captain to go around. ATC is calling us saying they have a low altitude alert; go around; and I hear CAUTION TERRAIN; TOO LOW TERRAIN; PULL UP. I'm now yelling at the Captain to 'GO AROUND PULL UP!' I'm grabbing for the controls because I don't see him reacting. My display now has red terrain on it and I don't have any lateral guidance on my flight director. The Captain said he was going around and told me he was climbing. Tower then told us to climb to 3000 ft and gave us a heading. We still don't have any lateral guidance and HDG mode won't engage. We finally get the aircraft stable; cleaned up on the right heading; and the Captain was now telling me I WANT 20L. I request 20L and then I have to listen to ATC telling us about the same braking action report on 20L and when they say poor; the Captain is saying 4. Then the Captain wants to argue out loud with me about he's saying '4' not 'poor'. I go ahead and just start briefing the ILS approach to 20L and making sure all the Captain was doing was flying the airplane. I programmed the FMC; made sure we both had the right frequency; and then landed without incident. The braking action was good. When we got to the gate; the Captain apologized for putting us in that position.I believe ATC put us in a bad position by not giving us a choice or time to make a decision. By turning us and clearing us for an approach we were not prepared for; this put us immediately into the red. Even though he was trying to be helpful by giving us the LOC frequency; there was not enough time to brief and make sure we were prepared to fly the approach in IMC conditions. We failed to recognize the threat and stop the approach right there. With the current weather conditions being an additive; I\'m sure getting on the ground was a priority rather than getting beat up by the turbulence and heavy rain with extended vectors. I was immediately overloaded by changing frequencies; talking to Tower; and trying to configure the aircraft and pull up the right approach plate on my iPad. Then with the distraction of flying through the LOC; the Captain disconnecting the autopilot; and hand flying; I never finished what I was doing.


Second narrative: Third leg of the third and last day of the pairing. As the weather in ZZZ was low and light rain was reported; I briefed the STAR and the desired approach; the RNAV Z to 20L. ATC told us he could get us the left; but wasn't sure if we could get the RNAV approach; so we went over the ILS to 20L as the backup approach. After crossing the final point on the STAR; ATC told us we would fly the ILS approach. At this point we were essentially on a downwind leg. We quickly reprogrammed the box; reset the DA; and prepared for the ILS approach.While descending to 3000 ft MSL; ATC gave us a base turn. Almost immediately thereafter we heard that a Company aircraft had reported braking action 'Poor' on 20L; and ATC asked us what we wanted to do. The FO and I briefly discussed it; and I said I wanted to continue to 20L. I thought it was extremely unlikely that the report was accurate; when only light rain was falling. It didn't matter; however; as ATC directed us to the ILS to 20R; gave us a dogleg turn; told us to descend to 2000 ft MSL; and cleared us for the approach. At this point; we were only 10 miles out; and unprepared for this approach.While the better course of action would have been to go around early and set up more deliberately for the new approach; we tried to quickly reprogram and reset once again. We were partially configured with landing gear down and flaps 15. I selected VOR/LOC; and the flight director indicated VOR/LOC capture. However; the aircraft didn't appear to capture the final approach course; flying through it to the left of course. I attempted to correct back as (now) Tower informed us of our drift. I then noticed that we were starting to go above glide path as well. I clicked off the autopilot while the FO was trying to find out why our course guidance didn't appear to be working. Distracted by these several issues; I inadvertently entered a much steeper descent than I had intended. Within a few seconds; we had gone from fully automated and on course to fully manual with no reliable course or vertical guidance. The first indication of trouble was Tower telling us we were below glide path. Then the GPWS gave me its several warnings in rapid order: SINK RATE; TOO LOW TERRAIN; and PULL UP. The FO also strongly directed a go-around. I applied maximum power and performed the escape maneuver. I don't know our altitude or sink rate during these brief hectic moments. I do know that I was well behind the aircraft; and was; in our current language; 'in the red.' The FO; as Pilot Monitoring; by his forceful intervention; helped bring me back toward the green; and the rest of the story is uneventful: we followed directions to downwind; calmly briefed and flew the ILS approach to 20L (it turns out the Company aircraft had called the braking action as '4;' not 'poor'); and landed (we reported the braking action as 'good').There were several points at which I now recognize that I should have gone around or made other arrangements with ATC. I allowed myself to be pushed into a corner with artificial time constraints; and tried to make everything work. A calmer; and much safer; alternative would have been to extend the timeline by overflying the airport and coming back again more prepared.


Synopsis: B737 flight crew reported that during a rapid descent in IMC they flew through the localizer and received several warnings in rapid order 'SINK RATE'; 'TOO LOW TERRAIN'; and 'PULL UP'.