A B757 flight crew received a TCASII RA from an aircraft climbing to a lower altitude.

Attributes
ACN	584436
Time
Date	200306
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : irq.vortac
State Reference	SC
Altitude	msl bound lower : 26000 msl bound upper : 26500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	Do 328 TP (Turboprop)
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 20000 flight time type : 4500
ASRS Report	584436
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took precautionary avoidance action
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	Ambiguous

Narrative:

Flight cruising at FL260 in day VMC. TCASII gave 1 TA, followed by an immediate RA which directed a climb in excess of 1500 FPM. Autoplt disconnected, and the first officer told ATC that we were responding to a TCASII RA and climbing. The TCASII target on the scope was observed to be 2700 ft below us and climbing. The range was hard to discern. As we passed through FL265, the RA changed to a TA and eventually to just a target on the scope. The flight returned to FL260. We never saw the conflict aircraft. ATC apologized for not calling out the traffic. He told us it was a dornier jet climbing to FL250.

Original NASA ASRS Text

Title: A B757 FLT CREW RECEIVED A TCASII RA FROM AN ACFT CLBING TO A LOWER ALT.

Narrative: FLT CRUISING AT FL260 IN DAY VMC. TCASII GAVE 1 TA, FOLLOWED BY AN IMMEDIATE RA WHICH DIRECTED A CLB IN EXCESS OF 1500 FPM. AUTOPLT DISCONNECTED, AND THE FO TOLD ATC THAT WE WERE RESPONDING TO A TCASII RA AND CLBING. THE TCASII TARGET ON THE SCOPE WAS OBSERVED TO BE 2700 FT BELOW US AND CLBING. THE RANGE WAS HARD TO DISCERN. AS WE PASSED THROUGH FL265, THE RA CHANGED TO A TA AND EVENTUALLY TO JUST A TARGET ON THE SCOPE. THE FLT RETURNED TO FL260. WE NEVER SAW THE CONFLICT ACFT. ATC APOLOGIZED FOR NOT CALLING OUT THE TFC. HE TOLD US IT WAS A DORNIER JET CLBING TO FL250.

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.