Pct controller issuing a visual approach to dca noted the aircraft departing the confines of class B...

Narrative:

I issued air carrier X to 'cross 10 DME at or above 2;500 ft; cleared mount vernon visual runway one.' this clearance would never have taken the pilot outside of the class bravo airspace. A VFR aircraft on the sfra frequency was flying right below the class bravo at 2;400 ft. I issued timely traffic to the air carrier X pilot. The pilot received a TCAS RA from the VFR aircraft. I verified with the pilot that the TCAS told him to descend and he said yes. I informed him that he was now outside of the class bravo. At the time of the event; I was on position for well over an hour and a half. And there was a class bravo airwork plane that was flying east/west lines for the duration of my time on position that made the session very difficult. That is why it was necessary not to have the arrivals into dca too high at all. And as I stated; I never issued anything that would have taken the aircraft outside of the bravo and issued a traffic call about the VFR sfra traffic. No error was made. Expand the class bravo 1;500 ft shelf much further south of dca. The pilots for dca need to be able to get low enough to make a stabilized approach.

Original NASA ASRS Text

Title: PCT Controller issuing a Visual Approach to DCA noted the aircraft departing the confines of Class B in response to a TCAS RA; the reporter advocated expansion of the existing Class B airspace.

Narrative: I issued Air Carrier X to 'Cross 10 DME at or above 2;500 FT; cleared Mount Vernon Visual Runway One.' This clearance would never have taken the pilot outside of the Class Bravo airspace. A VFR aircraft on the SFRA frequency was flying right below the Class Bravo at 2;400 FT. I issued timely traffic to the Air Carrier X pilot. The pilot received a TCAS RA from the VFR aircraft. I verified with the pilot that the TCAS told him to descend and he said yes. I informed him that he was now outside of the Class Bravo. At the time of the event; I was on position for well over an hour and a half. And there was a Class Bravo airwork plane that was flying East/West lines for the duration of my time on position that made the session very difficult. That is why it was necessary not to have the arrivals into DCA too high at all. And as I stated; I never issued anything that would have taken the aircraft outside of the Bravo and issued a traffic call about the VFR SFRA traffic. No error was made. Expand the Class Bravo 1;500 FT shelf much further south of DCA. The pilots for DCA need to be able to get low enough to make a stabilized approach.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1118406
Time
Date	201309
Local Time Of Day	0001-0600
Place
Locale Reference	PCT.TRACON
State Reference	VA
Aircraft 1
Make Model Name	EMB ERJ 190/195 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Amateur/Home Built/Experimental
Operating Under FAR Part	Part 91
Route In Use	None
Flight Plan	VFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	No Specific Anomaly Occurred All Types

Pct controller issuing a visual approach to dca noted the aircraft departing the confines of class B in response to a TCAS RA; the reporter advocated expansion of the existing class B airspace.