Date: 201512
Local time of day: 1201-1800
Location: HSV.TRACON, AL
Flight conditions: VMC
Light: Night
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Ambulance
Flight phase: Final Approach
Airspace: Class C HSV
ATC / advisory: TRACON HSV
Reporter organization: Air Taxi
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Not Flying; First Officer
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: We were vectored by approach to the East for runway 18L. We were vectored well North of the airport; and then to the west. We were then given traffic; and then cleared for a visual approach. At some point; we lost sight of HSV; and acquired HUA by mistake. As we proceeded inbound to the runway; we had traffic called to us; and then were given a go-around. It was at this point that we realized we had the wrong airport identified. We were given straight ahead to 4;000 feet; and then heading 090. The first officer and I are filling this out together; and after discussion we believe the biggest contributing factor in this situation is that we fly international missions frequently. So in this case; we failed to put proper emphasis on this flight as we naturally do in all of our flights. This is; of course; not an excuse; just that we could have put more emphasis on this flight so as not to become complacent.  Further contributing factors were several. First; the lights on runway 18L at HSV were not very brightly lit. The lights of runway 17 at Redstone; HUA; were lit to full intensity. So as we were vectored to the west and given the traffic the brighter runway visually prevailed.  Also there was a shift change with the approach controller we were talking to. This happened when we were on the downwind leg. We believe this extended our downwind leg further; and thus caused two things: first; for us; that as close as the two airports are together; by the time we were turned back to where we could see the runway; visually; the two airports seemed way closer together. Secondly; at some point; the new controller asked which airport we were going to; so we believe there was confusion there; as well; which allowed the approach to continue maybe a bit further than would have otherwise.After much discussion; we believe in moving forward; what we will do to prevent further occurrence; is; #1...that we will not consider any flight of lesser importance. We will consider every takeoff and landing to be of utmost importance. Complacency is not an option. #2...We intend to; whenever going in to a runway served by an approach; to shoot that approach even if in VFR.


Second narrative: [Report narrative contained no additional information.]


Synopsis: Flight crew reported lining up for HUA airport instead of their destination; HSV; during a night visual approach.