B737-200 crew had a near midair collision with an unknown aircraft in tpa class B.

Attributes
ACN	577726
Time
Date	200303
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : tpa.airport
State Reference	FL
Altitude	agl bound lower : 900 agl bound upper : 1600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : tpa.tracon tower : tpa.tower
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude climbout : initial ground : preflight
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : private pilot : multi engine pilot : instrument pilot : flight engineer pilot : commercial pilot : atp pilot : cfi
Experience	flight time last 90 days : 61 flight time total : 7500 flight time type : 61
ASRS Report	577726
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : nmac non adherence : required legal separation non adherence : published procedure
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb
Resolutory Action	flight crew : took evasive action
Miss Distance	vertical : 400
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Inter Facility Coordination Failure Operational Error

Narrative:

Climbing through 900 ft AGL out of tampa international, TCASII gave an instruction to descend. The climb was stopped at 1600 ft AGL, and we descended to 1000 ft MSL, at which time the conflict was resolved. This event could have been avoided if the tower had advised us of the VFR traffic crossing the field at the time we were cleared for takeoff.

Original NASA ASRS Text

Title: B737-200 CREW HAD A NMAC WITH AN UNKNOWN ACFT IN TPA CLASS B.

Narrative: CLBING THROUGH 900 FT AGL OUT OF TAMPA INTL, TCASII GAVE AN INSTRUCTION TO DSND. THE CLB WAS STOPPED AT 1600 FT AGL, AND WE DSNDED TO 1000 FT MSL, AT WHICH TIME THE CONFLICT WAS RESOLVED. THIS EVENT COULD HAVE BEEN AVOIDED IF THE TWR HAD ADVISED US OF THE VFR TFC XING THE FIELD AT THE TIME WE WERE CLRED FOR TKOF.

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.