Flight crew of mdt commuter had near midair collision with small aircraft in proximity of tpa.

Attributes
ACN	173667
Time
Date	199103
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : tpa
State Reference	FL
Altitude	msl bound lower : 2000 msl bound upper : 2200
Environment
Flight Conditions	Marginal
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : tpa
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Flight Phase	descent : approach descent other
Route In Use	approach : visual arrival other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 225 flight time total : 4100 flight time type : 1000
ASRS Report	173667
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : atp
Events
Anomaly	conflict : nmac other anomaly other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Miss Distance	horizontal : 500 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Cleared for visibility approach. Began descent from 2600' MSL and slowed approach because we were ahead of schedule. As we reached 2000' MSL PIC spotted traffic 200' above us and slightly to our left front, continuing on a straight line course from our right to left. If we had maintained normal speed on descent (approximately 200 KTS) at that distance we would have been at the same place at the same time. Asked tower if he was 'painting' traffic, he said no. Our TCAS ii showed nothing. We were within TCA and assumed aircraft would have xponders. Small aircraft airplane was almost directly south of vandenburg field (civil strip) which has a n-s runway and is located north of approach to runway 27 at tampa. Believe the probably departed from there. Review of TCA 'sketch' shows a lack of clrcut definition of floor of TCA in near miss area. Pilot of small aircraft probably believes he was under 3000' floor portion, while I believe he was within 1200' floor portion. But charts do not show recognizable features (like hwys). Irregular shape precludes DME use. I am now changing my procedure on visuals to 27 and plan not to accept clearance for 2600' until west of vandenburg field even though regulations call for aircraft to have xponders within 30 NM of TCA airports.

Original NASA ASRS Text

Title: FLT CREW OF MDT COMMUTER HAD NMAC WITH SMA IN PROX OF TPA.

Narrative: CLRED FOR VIS APCH. BEGAN DSNT FROM 2600' MSL AND SLOWED APCH BECAUSE WE WERE AHEAD OF SCHEDULE. AS WE REACHED 2000' MSL PIC SPOTTED TFC 200' ABOVE US AND SLIGHTLY TO OUR L FRONT, CONTINUING ON A STRAIGHT LINE COURSE FROM OUR R TO L. IF WE HAD MAINTAINED NORMAL SPD ON DSNT (APPROX 200 KTS) AT THAT DISTANCE WE WOULD HAVE BEEN AT THE SAME PLACE AT THE SAME TIME. ASKED TWR IF HE WAS 'PAINTING' TFC, HE SAID NO. OUR TCAS II SHOWED NOTHING. WE WERE WITHIN TCA AND ASSUMED ACFT WOULD HAVE XPONDERS. SMA AIRPLANE WAS ALMOST DIRECTLY S OF VANDENBURG FIELD (CIVIL STRIP) WHICH HAS A N-S RWY AND IS LOCATED N OF APCH TO RWY 27 AT TAMPA. BELIEVE THE PROBABLY DEPARTED FROM THERE. REVIEW OF TCA 'SKETCH' SHOWS A LACK OF CLRCUT DEFINITION OF FLOOR OF TCA IN NEAR MISS AREA. PLT OF SMA PROBABLY BELIEVES HE WAS UNDER 3000' FLOOR PORTION, WHILE I BELIEVE HE WAS WITHIN 1200' FLOOR PORTION. BUT CHARTS DO NOT SHOW RECOGNIZABLE FEATURES (LIKE HWYS). IRREGULAR SHAPE PRECLUDES DME USE. I AM NOW CHANGING MY PROC ON VISUALS TO 27 AND PLAN NOT TO ACCEPT CLRNC FOR 2600' UNTIL W OF VANDENBURG FIELD EVEN THOUGH REGS CALL FOR ACFT TO HAVE XPONDERS WITHIN 30 NM OF TCA ARPTS.

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.