Flight crew receives TCASII TA then RA. Climbs, near midair collision.

Attributes
ACN	215440
Time
Date	199207
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : nas
State Reference	FO
Altitude	msl bound lower : 10700 msl bound upper : 11700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : nas tower : lvk
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 6200 flight time type : 400
ASRS Report	215440
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 270 flight time total : 2700 flight time type : 1450
ASRS Report	215678
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : nmac other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 0 vertical : 400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

Flight from miami, fl, to governor's harbor, bahamas. Cruising at 11000 ft MSL under nassau, bahamas approach control. The controller issued a traffic (1 O'clock). We search for it did not see it. Next came a TA issued by the TCASII showing the traffic at 10500 ft on a collision course then an RA was issued with the traffic being at 10600 ft and climbing now. We followed the RA and climb to avoid the traffic. After we passed that traffic the 'clear of traffic' was issued at that time the traffic was showing an altitude of 10700 ft climbing. We then resumed the previously assigned cruising altitude of 11000 ft, notified nassau, bahamas approach control of the encounter. We never saw the traffic. I believe, even though we did not see the traffic, the aircraft was there and the TCASII worked as advertised, tracking it up to maximum range.

Original NASA ASRS Text

Title: FLC RECEIVES TCASII TA THEN RA. CLBS, NMAC.

Narrative: FLT FROM MIAMI, FL, TO GOVERNOR'S HARBOR, BAHAMAS. CRUISING AT 11000 FT MSL UNDER NASSAU, BAHAMAS APCH CTL. THE CTLR ISSUED A TFC (1 O'CLOCK). WE SEARCH FOR IT DID NOT SEE IT. NEXT CAME A TA ISSUED BY THE TCASII SHOWING THE TFC AT 10500 FT ON A COLLISION COURSE THEN AN RA WAS ISSUED WITH THE TFC BEING AT 10600 FT AND CLBING NOW. WE FOLLOWED THE RA AND CLB TO AVOID THE TFC. AFTER WE PASSED THAT TFC THE 'CLR OF TFC' WAS ISSUED AT THAT TIME THE TFC WAS SHOWING AN ALT OF 10700 FT CLBING. WE THEN RESUMED THE PREVIOUSLY ASSIGNED CRUISING ALT OF 11000 FT, NOTIFIED NASSAU, BAHAMAS APCH CTL OF THE ENCOUNTER. WE NEVER SAW THE TFC. I BELIEVE, EVEN THOUGH WE DID NOT SEE THE TFC, THE ACFT WAS THERE AND THE TCASII WORKED AS ADVERTISED, TRACKING IT UP TO MAX RANGE.

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.