Date: 201205
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: 0.75
Light: Daylight
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: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Physiological - Other; Situational Awareness; Training / Qualification
Anomaly: Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Executed Go Around / Missed Approach
Contributing factors: Weather; Staffing; Company Policy; Human Factors
Primary problem: Human Factors

Narrative: An approach was briefed for Runway 30L with the weather reported as heavy rain; but the visibility above minimums. Radar showed heavy precipitation; but no convective activity; and there were flights landing ahead of us. The First Officer was the pilot flying and since the [reported weather was better than that which would require the Captain to fly the approach per our FOM] I thought it would be a fairly straightforward event. At 1;000 FT we encountered the heavy rain; airspeed held steady with negligible wind gusts; and the wipers were selected to high. The First Officer reported to me around 600 FT that he was starting to pick up some lights; which I thought was odd since we I couldn't see any. I immediately began to think he was mistaking some lights on the ground for the approach lights and I instantly became very sensitive to the possibility that something might go wrong. At the 'approaching minimums' call; the First Officer reported 'landing' and disengaged the autopilot and autothrottles. It was raining so hard at this time that I personally could only see the runway between sweeps of the wipers; so that it was as if you were seeing a stop motion picture only about 40% of the time. I was worried about drift and our ability to assure a proper touchdown when I perceived that the VASI lights were moving towards our flight path. While the First Officer; who was flying; made no comment about the situation; I had an overwhelming sense that we were in imminent danger and without delay shouted 'go around!' The First Officer immediately performed a go-around and we climbed out. I really don't know how low we were at that moment; but I'm guessing we were below 100 FT. We leveled off at 4;000 FT and got ourselves situated. I explained my perceptions to the First Officer and stated that I would be more comfortable flying the next approach on the HUD with a flap setting of 40 vice the 30 setting we had just used. We re-briefed the approach; went through the HGS checklist; talked about our fuel state and divert options; made a PA to the passengers; and hooked back in for another go at it.I made the next approach and landing. It helped a great deal (for me anyway) to be able to have the HGS guidance and to be flying the plane. We touched down uneventfully in heavy rain and experienced fair braking; much less than you normally get on a wet runway. We pulled into the gate and shut down and I noticed my hands were shaking a bit. You know; you don't want to be mean guy to your First Officer and tell him that you'd feel more comfortable flying because he's on probation and you really don't trust him; but having the HUD and 16 years experience vice his 8 months would really give me the warm and fuzzies. This guy was a great pilot and a good guy and what happened probably had nothing to do with him; but can I be honest with you guys in safety and tell you this scared the crap out of me? I really; no kidding; thought for a moment we were about to land off the runway.I'm sure I'm not seeing the whole picture; but whatever you all find out; I'm sure I will be using this as (yet another) learning experience.In the future I could: 1. hold until heavy rain clears the final; 2. use the HUD more; 3. not be reluctant to take the aircraft and fly the approach myself if I think it would offer a better level of safety.




Synopsis: A B737-700 Captain; concerned that his First Officer was visually continuing a low minima approach in heavy rains based on inaccurate assessment of the visible runway environment; directed a go-around at low altitude. A second successful approach was flown by the Captain assisted by a HUD system accessible to him in the left seat.