Date: 201310
Local time of day: 0601-1200
Location: D01.TRACON, CO
Flight conditions: VMC
Light: Night
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
ATC / advisory: TRACON D01
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Situational Awareness
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: We were on a STAR coming into DEN when we were given vector off of the STAR.  We were then cleared to descend to 9;000 feet.  As we approached the airport (approximately 15-20 miles out) ATC asked if we had the airport in sight. The Captain was the non-flying pilot and he told ATC that we had the field in sight.  We were then cleared for a visual approach to Runway 35L.  We were set up to intercept the localizer at approximately a 65 degree angle from the southeast. I checked the approach plate for the ILS RWY35L approach and saw that the FAF was at 7;000 feet.  I dialed 7;000 feet into the altitude pre-select and started a shallow descent.  We were approximately 11 miles from the airport and I had stopped the descent at 7;500 feet when ATC issued us an altitude alert and advised us the minimum vectoring altitude for that area was 8;000 feet.  I had the airport and the ground in sight the entire time; however due to the bright lights on the runway and the dark area to the southeast of the runway I had the illusion that we were closer to the airport than we really were.  I initiated a climb back to 8;000 feet and we intercepted the glide slope at 8;000 feet.  We landed safely without further incident. The root cause of this incident was a momentary lack of situational awareness with my exact distance from the airport and further compounded by the fact that we were approaching the airport/localizer from a sharp angle that was in between two fixes.  A contributing factor was the night time illusion or 'black hole effect'. Those factors led me to believe that the FAF altitude was the better choice rather than an altitude of a fix further out on the approach.   To avoid this from occurring in the future I will pick the more conservative of the altitudes when intercepting a localizer between two fixes to ensure I never get too low on an approach.  I also will include any potential night time illusions during my approach briefing to make the other pilot in the cockpit aware of the potential hazard. Also; if there is any doubt as to what a safe altitude for a particular area would be when not on an instrument approach; the MSA or the MVA should be used.




Synopsis: CRJ-200 First Officer reported he descended below MVA on a night visual to DEN; citing lack of situational awareness as a causal factor.