B737NG captain reported exceeding 200 kts below den class B airspace while being vectored by ATC.

Attributes
ACN	1620690
Time
Date	201902
Place
Locale Reference	DEN.Airport
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737 Next Generation Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Last 90 Days 120 Flight Crew Type 2996
Person 2
Function	First Officer Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 146.78 Flight Crew Type 4153
Events
Anomaly	ATC Issue All Types Airspace Violation All Types Deviation - Procedural FAR Deviation - Speed All Types

Narrative:

We were told to descend with at least 2;000 FPM at roughly the same time a heading to the southwest was issued as initial vectors for the runway. To comply; we kept the speed high (320 knots or so). After leveling at 10;000 feet; approach gave us a descent to 9000 feet and then switched us to another approach control frequency. The first officer slowed to 250 knots and began the descent while I tuned the radio and switched frequencies. Upon check in; the new controller asked; 'did anyone tell you that you exited the class bravo?' I replied that I was not aware of that. Immediately; I asked the first officer to slow to 200 knots in case we were in fact below the class B airspace. I looked at the 10-1B chart; entered our destination in the fix page; and noted that we were on the 140 radial and 21NM; just 1 mile outside the class B section where our speed would have been appropriate. Admittedly; this felt to me very much like a setup by the controllers. In no way did we intend to exceed the class B boundaries. But their requests for expedited descents and their vectors to final placed us just slightly outside the class B boundaries. With few other airplanes in our area (based on TCAS display); it would have been easy for the controllers to have at least prompted us prior to exiting the bravo or to have vectored us just slightly farther west in order to stay inside the appropriate class B boundaries.

Original NASA ASRS Text

Title: B737NG Captain reported exceeding 200 kts below DEN Class B airspace while being vectored by ATC.

Narrative: We were told to descend with at least 2;000 FPM at roughly the same time a heading to the southwest was issued as initial vectors for the runway. To comply; we kept the speed high (320 Knots or so). After leveling at 10;000 feet; Approach gave us a descent to 9000 feet and then switched us to another Approach Control frequency. The First Officer slowed to 250 knots and began the descent while I tuned the radio and switched frequencies. Upon check in; the new Controller asked; 'Did anyone tell you that you exited the Class Bravo?' I replied that I was not aware of that. Immediately; I asked the First Officer to slow to 200 knots in case we were in fact below the Class B airspace. I looked at the 10-1B chart; entered our destination in the fix page; and noted that we were on the 140 radial and 21NM; just 1 mile outside the Class B section where our speed would have been appropriate. Admittedly; this felt to me very much like a setup by the controllers. In no way did we intend to exceed the Class B boundaries. But their requests for expedited descents and their vectors to final placed us just slightly outside the Class B boundaries. With few other airplanes in our area (based on TCAS display); it would have been easy for the controllers to have at least prompted us prior to exiting the Bravo or to have vectored us just slightly farther west in order to stay inside the appropriate Class B boundaries.

Data retrieved from NASA's ASRS site 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.