An air carrier pilot on approach to den 35L descended below the glideslope setting off ATC's low alt...

Attributes
ACN	862115
Time
Date	200911
Local Time Of Day	0001-0600
Place
Locale Reference	DEN.Airport
State Reference	CO
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 35 Flight Crew Total 12000 Flight Crew Type 4000
Events
Anomaly	Deviation - Altitude Undershoot Deviation - Procedural Clearance Flight Deck / Cabin / Aircraft Event Other / Unknown Inflight Event / Encounter CFTT / CFIT

Narrative:

Cleared direct to OM for visual approach to runway 35L den. Acquired the airport and runway 35R. Initiated a turn inbound to the facility and started a descent. Commanded stop descent at 6;000 ft MSL realizing visual picture and altitude were incorrect for our position on the approach. Subsequently received glideslope alert and tower called low altitude alert. Commanded an immediate climb to 7;000 ft MSL and completed a stable approach to landing. Contributing factors: black hole approach. Perception of being high for the arrival. Time of day with both crew being up most of the previous day. Momentary distraction of visually acquiring the designated runway and a possible false glideslope in the cockpit. In debriefing this event we identified several indicators that should have alerted us to our loss of situational awareness. It was apparent we were seeing all the indications of our low approach but for a few moments we were not making the connection that was what was occurring. For just a few moments on the approach we both became subtly incapacitated.

Original NASA ASRS Text

Title: An Air Carrier pilot on approach to DEN 35L descended below the glideslope setting off ATC's Low Altitude Alert. The crew reported fatigue and the black hole effect as contributory factors.

Narrative: Cleared direct to OM for visual approach to Runway 35L DEN. Acquired the airport and Runway 35R. Initiated a turn inbound to the facility and started a descent. Commanded stop descent at 6;000 FT MSL realizing visual picture and altitude were incorrect for our position on the approach. Subsequently received glideslope alert and Tower called low altitude alert. Commanded an immediate climb to 7;000 FT MSL and completed a stable approach to landing. Contributing Factors: Black Hole Approach. Perception of being high for the arrival. Time of day with both crew being up most of the previous day. Momentary distraction of visually acquiring the designated runway and a possible false glideslope in the cockpit. In debriefing this event we identified several indicators that should have alerted us to our loss of situational awareness. It was apparent we were seeing all the indications of our low approach but for a few moments we were not making the connection that was what was occurring. For just a few moments on the approach we both became subtly incapacitated.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

An air carrier pilot on approach to den 35L descended below the glideslope setting off ATC's low altitude alert. The crew reported fatigue and the black hole effect as contributory factors.