B757-200 captain was concerned about operating below las class B on the VOR DME-a approach.

Attributes
ACN	536809
Time
Date	200201
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl single value : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : l30.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 14000 flight time type : 2000
ASRS Report	536809
Person 2
Affiliation	government : faa
Function	controller : supervisor
Events
Anomaly	non adherence : published procedure non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance Airspace Structure Chart Or Publication FAA
Primary Problem	ATC Human Performance
Air Traffic Incident	other
Situations
Chart	approach : vor dme a

Narrative:

Inadvertent descent below the floor of las class B airspace by approximately 300 ft before mistake was recognized and corrected by the PNF (captain). Las class B airspace commercial chart is too complex. Also the VOR DME-a approach has stepdown altitudes that are below the class B airspace floors. This adds to confusion. Callback conversation with reporter revealed the following information: the las TRACON supervisor indicated the next revision of las class B will correct the idented problem, by dropping the 800 ft floor to a lower altitude. He also indicated that currently the approach controller is supposed to advise the crew that the VOR DME-a approach calls for operation that is below the class B floor.

Original NASA ASRS Text

Title: B757-200 CAPT WAS CONCERNED ABOUT OPERATING BELOW LAS CLASS B ON THE VOR DME-A APCH.

Narrative: INADVERTENT DSCNT BELOW THE FLOOR OF LAS CLASS B AIRSPACE BY APPROX 300 FT BEFORE MISTAKE WAS RECOGNIZED AND CORRECTED BY THE PNF (CAPT). LAS CLASS B AIRSPACE COMMERCIAL CHART IS TOO COMPLEX. ALSO THE VOR DME-A APCH HAS STEPDOWN ALTS THAT ARE BELOW THE CLASS B AIRSPACE FLOORS. THIS ADDS TO CONFUSION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE LAS TRACON SUPVR INDICATED THE NEXT REVISION OF LAS CLASS B WILL CORRECT THE IDENTED PROB, BY DROPPING THE 800 FT FLOOR TO A LOWER ALT. HE ALSO INDICATED THAT CURRENTLY THE APCH CTLR IS SUPPOSED TO ADVISE THE CREW THAT THE VOR DME-A APCH CALLS FOR OP THAT IS BELOW THE CLASS B FLOOR.

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.