Flight Crew Air Transport Pilot (ATP)
Workload
Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Unstabilized Approach
Flight Crew Overcame Equipment Problem; Flight Crew Executed Go Around / Missed Approach
Weather; Aircraft; Human Factors
On approach vectors; autopilot was not capturing the LOC; so I; PF; clicked off the autopilot. As soon as I did; I lost my flight director. I was immediately faced with a raw data; in the weather; hand flown; instrument approach. The approach was not stable so we executed a go-around. During the miss; still hand flown; assigned 2500 ft; I climbed to 2900 ft. The controller didn't say anything so I don't think there was a conflict. The second approach was similar to the first. The third approach resulted in a successful approach and landing.I really had my hands full of airplane and the normal automation was unavailable. Attempts to reestablish the autopilot were unsuccessful until being vectored for the third approach. More aggressive attention to the altitude. Maybe let my copilot fly while I tried to troubleshoot.
B737-800 Captain reported going around after an autopilot anomaly resulted in an unstable hand-flown instrument approach.