CL65 crew descended below the configns of class B airspace. They did not descend on the GS.

Attributes
ACN	594936
Time
Date	200309
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : den.airport
State Reference	CO
Altitude	msl bound lower : 7000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d01.tracon
Operator	common carrier : air carrier
Make Model Name	Regional Jet CL65, Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 4300 flight time type : 500
ASRS Report	594936
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	airspace violation : exit altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : far non adherence : company policies non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : dme other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : returned to assigned airspace
Supplementary
Problem Areas	Airspace Structure Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On visual approach to runway 35L at 250 KIAS, I descended to the minimum GS intercept altitude of 7000 ft about 15 mi from the airport. Once there, I thought it seemed a little low and possibly below the class B floor, so I started an immediate speed reduction, and had the first officer turned to the den class B chart. He confirmed we were below the floor. We needed to be at least 8000 ft until 10 mi. By then we were below 200 KIAS and had re-entered the class B airspace. During this approach, I was referring to the ILS runway 35L chart to back up the visual approach. I should have reviewed the class B chart as part of my approach planning. I also should have used the normal GS intercept altitude instead of the minimum, which I shall in the future. Doing so will safely keep me within the appropriate airspace.

Original NASA ASRS Text

Title: CL65 CREW DSNDED BELOW THE CONFIGNS OF CLASS B AIRSPACE. THEY DID NOT DSND ON THE GS.

Narrative: ON VISUAL APCH TO RWY 35L AT 250 KIAS, I DSNDED TO THE MINIMUM GS INTERCEPT ALT OF 7000 FT ABOUT 15 MI FROM THE ARPT. ONCE THERE, I THOUGHT IT SEEMED A LITTLE LOW AND POSSIBLY BELOW THE CLASS B FLOOR, SO I STARTED AN IMMEDIATE SPD REDUCTION, AND HAD THE FO TURNED TO THE DEN CLASS B CHART. HE CONFIRMED WE WERE BELOW THE FLOOR. WE NEEDED TO BE AT LEAST 8000 FT UNTIL 10 MI. BY THEN WE WERE BELOW 200 KIAS AND HAD RE-ENTERED THE CLASS B AIRSPACE. DURING THIS APCH, I WAS REFERRING TO THE ILS RWY 35L CHART TO BACK UP THE VISUAL APCH. I SHOULD HAVE REVIEWED THE CLASS B CHART AS PART OF MY APCH PLANNING. I ALSO SHOULD HAVE USED THE NORMAL GS INTERCEPT ALT INSTEAD OF THE MINIMUM, WHICH I SHALL IN THE FUTURE. DOING SO WILL SAFELY KEEP ME WITHIN THE APPROPRIATE AIRSPACE.

Data retrieved from NASA's ASRS site as of July 2007 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.