An EMB120 flight crew feels that altitudes below dfw class B airspace could be potentially risky.

Attributes
ACN	453455
Time
Date	199909
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : ttt.vor
State Reference	TX
Altitude	msl single value : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : instrument pilot : cfi pilot : atp pilot : commercial
Experience	flight time last 90 days : 235 flight time total : 6700 flight time type : 5400
ASRS Report	453455
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Flight Crew Human Performance Airspace Structure
Primary Problem	Ambiguous
Situations
ATC Facility	procedure or policy : d10.tracon
Airspace Structure	class b : dfw.b

Narrative:

After switching to departure, we were given several vectors in a northerly direction to join the tri-gate SID. Departure kept us at 4000 ft until we were several mi past the boundary of class B airspace. The floor of the class B airspace in our area (within the class B boundaries) had been 4000 ft for about the last 10 NM. We saw several TCASII targets and were able to acquire them all visually. However, this is not always the case. Dfw's departure procedures put my passenger, my crew, and my company's aircraft at risk when we are vectored out the sides of the class B airspace at low altitudes. We do our best to see and avoid, but we can't catch every VFR target transitioning around the class B airspace, not in radio contact with our departure controller. It is only a matter of time before this practice results in an accident.

Original NASA ASRS Text

Title: AN EMB120 FLC FEELS THAT ALTS BELOW DFW CLASS B AIRSPACE COULD BE POTENTIALLY RISKY.

Narrative: AFTER SWITCHING TO DEP, WE WERE GIVEN SEVERAL VECTORS IN A NORTHERLY DIRECTION TO JOIN THE TRI-GATE SID. DEP KEPT US AT 4000 FT UNTIL WE WERE SEVERAL MI PAST THE BOUNDARY OF CLASS B AIRSPACE. THE FLOOR OF THE CLASS B AIRSPACE IN OUR AREA (WITHIN THE CLASS B BOUNDARIES) HAD BEEN 4000 FT FOR ABOUT THE LAST 10 NM. WE SAW SEVERAL TCASII TARGETS AND WERE ABLE TO ACQUIRE THEM ALL VISUALLY. HOWEVER, THIS IS NOT ALWAYS THE CASE. DFW'S DEP PROCS PUT MY PAX, MY CREW, AND MY COMPANY'S ACFT AT RISK WHEN WE ARE VECTORED OUT THE SIDES OF THE CLASS B AIRSPACE AT LOW ALTS. WE DO OUR BEST TO SEE AND AVOID, BUT WE CAN'T CATCH EVERY VFR TARGET TRANSITIONING AROUND THE CLASS B AIRSPACE, NOT IN RADIO CONTACT WITH OUR DEP CTLR. IT IS ONLY A MATTER OF TIME BEFORE THIS PRACTICE RESULTS IN AN ACCIDENT.

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.