Date: 201401
Local time of day: 1201-1800
Location: D01.TRACON, CO
Flight conditions: VMC
Light: Dusk
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B DEN; Class E D01
ATC / advisory: TRACON D01; Tower DEN
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Situational Awareness; Distraction
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action; Flight Crew Returned To Departure Airport; Flight Crew Became Reoriented; Flight Crew FLC complied w / Automation / Advisory
Contributing factors: Weather; Airport; Procedure
Primary problem: Ambiguous

Narrative: I was the pilot monitoring and we were descending via the BOSSS 1 Arrival into DEN.  ATC then cleared us direct to DYMON (Runway 35L Final Approach Fix) and told us to descend and maintain 9;000 FT.  Approximately 20 NM south of the airport; and as we were descending between 12;000 FT and 9;000 FT; the First Officer and I confirmed that we had the field in sight.  I advised this to ATC; and they cleared us for the visual approach to Runway 35L.  The First Officer set 7;000 FT (the GS intercept altitude at DYMON) in the altitude selector and began slowing and configuring for the approach.  He called for Flaps 1 after we had slowed to 210 KIAS.  My eyes were focused mainly outside the aircraft scanning for traffic; as conditions were VMC and we were in a busy terminal environment.  I began to notice that we were descending rather rapidly and were still pretty far from the airport.  As we began to level off at 7;000 FT; ATC issued us a low altitude alert.  They also notified us that we had descended below the floor of the Class B airspace and told us that the Minimum Vectoring Altitude in that sector was 7;500 FT.  We climbed back up to 7;500 FT and they informed us that we reentered the Class B airspace.  The Controller then handed us off to Denver Tower and we continued the approach and landing in an uneventful manner.  The number one thing was that both of us should have maintained better situational awareness though out the whole approach sequence.  We were descending in FLCH mode; which is pretty common in the terminal environment.  Unfortunately; I didn't notice right away that we had a 30 knot headwind.  This headwind; combined with the Flaps 1 configuration; caused our descent profile to steepen way more that the typical 3-3.5 degrees one would expect with the throttles at flight idle.  By the time I noticed the unusually steep descent angle; we were already too low.  Selecting a shallower descent angle in VS or FPA mode would have prevented this from happening.


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


Synopsis: An air carrier crew flying a DEN Runway 35L visual was about sixteen miles from the runway when they descended to 7;000 FT and out of Class B airspace where ATC notified them about the error which they corrected by climbing to 7;500 FT.