Date: 201701
Local time of day: 0601-1200
Location: DEN.Airport, CO
Flight conditions: IMC
Weather elements / visibility: Fog; 1
Light: Daylight
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb; Initial Approach
Airspace: Class B DEN
ATC / advisory: TRACON D01; Tower DEN
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Human Factors; Weather
Primary problem: Human Factors

Narrative: While being vectored for ILS 35L at DEN latest ATIS indicated 900 ft ceilings and 1 mile visibility. Cat I auto flown ILS was briefed. While on final; ATC reported fog increasing in density with decreasing visibility; although still above 1800 RVR. Inside the FAF we heard flight in front of us go-around due to no ground contact at DA. I was therefore mentally ready to go-around. Captain; as PF; did not comment. Normal ILS; normal fallouts. At DA we were still IMC so at my 'minimums' call PF stated 'go-around' and selected TOGA. Initial pitch up seemed normal.  No call for flaps or setting missed approach altitude; so I prompted 'flaps 15?' and 'positive rate; gear up?' which the Captain acknowledged. As we continued the miss; pitch continued to increase and airspeed continued to decrease. I called out 'airspeed' two or three times; then when no action was taken; stated 'you need to reduce your pitch'; at which point we got an 'airspeed low' warning.  As the Captain finally reduced pitch; I advised ATC we were on the miss and they assigned a heading and altitude. As Captain began to turn; bank angle increased to 50 to 60 degrees and 'bank angle' sounded twice. I think at this point I missed a handoff to Approach Control; but I'm not sure. I called out 'watch your bank' and the Captain corrected.After the aircraft was back within parameters; acceleration and cleanup commenced.  A heading was assigned but we turned through it as the Captain kept trying to couple the autopilot with the aircraft out of trim.  Once the aircraft was trimmed; autopilot was coupled and we were vectored normally.  We discussed weather; fuel to alternate; and briefed a HGS (Heads-up Guidance System) approach to 35R as per ATC. After turning final; when Captain attempted to arm AIII mode we got an approach warning and 'NO AIII' message on the HGS control panel. We tried to recycle twice with no luck. ATC then reported weather right at CAT I minimums. We elected to re-bug CAT I minimums and flew the approach using the autopilot. Approach lights were seen right at the 'minimums' call and a normal; if firm; landing was made.At the gate; we were told by the Mechanic who came out to look at the HGS that there were no faults in the system but that exceedances in airspeed and bank had caused the system to 'lock' itself out; which was something that neither the Captain nor I knew about the system. I am not really sure how to prevent this occurrence as I have never experienced anything like this in my years of flying for 121 carriers. I think the Captain's lack of experience on the 737 and limited exposure to manually flown go-arounds were major factors.




Synopsis: B737 First Officer reported a missed approach at DEN where the aircraft experienced excessive pitch and bank. This 'locked out' the Heads-up Guidance System on the subsequent approach.