TCASII RA creates a potential conflict situation with other opposite direction traffic.

Attributes
ACN	266896
Time
Date	199403
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pvd
State Reference	RI
Altitude	msl bound lower : 20000 msl bound upper : 20500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 80 flight time total : 7000 flight time type : 80
ASRS Report	266896
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : took evasive action other
Consequence	Other
Miss Distance	vertical : 500
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

On a flight from bos to phl at FL200 we received a TA on our TCASII. We noticed an aircraft climbing 2600 ft below us. As we got closer, we received an RA to climb. We followed the RA. As soon as we could get a word into ZNY, we told them we were following an RA on our TCASII. The controller told us to descend immediately. We were at 20500 ft, and that other air carrier was at FL210, coming the opposite direction. The other air carrier was told to climb immediately and we descended back to FL200. ATC advised other air carrier that we received an 'erroneous TCASII.' I believe it was not an erroneous TCASII but, I believe that the TCASII was monitoring the aircraft climbing rate of climb and thought there would be a conflict. This is a problem I believe with TCASII. The TCASII did not take into account the other air carrier, only the aircraft climbing below us.

Original NASA ASRS Text

Title: TCASII RA CREATES A POTENTIAL CONFLICT SIT WITH OTHER OPPOSITE DIRECTION TFC.

Narrative: ON A FLT FROM BOS TO PHL AT FL200 WE RECEIVED A TA ON OUR TCASII. WE NOTICED AN ACFT CLBING 2600 FT BELOW US. AS WE GOT CLOSER, WE RECEIVED AN RA TO CLB. WE FOLLOWED THE RA. AS SOON AS WE COULD GET A WORD INTO ZNY, WE TOLD THEM WE WERE FOLLOWING AN RA ON OUR TCASII. THE CTLR TOLD US TO DSND IMMEDIATELY. WE WERE AT 20500 FT, AND THAT OTHER ACR WAS AT FL210, COMING THE OPPOSITE DIRECTION. THE OTHER ACR WAS TOLD TO CLB IMMEDIATELY AND WE DSNDED BACK TO FL200. ATC ADVISED OTHER ACR THAT WE RECEIVED AN 'ERRONEOUS TCASII.' I BELIEVE IT WAS NOT AN ERRONEOUS TCASII BUT, I BELIEVE THAT THE TCASII WAS MONITORING THE ACFT CLBING RATE OF CLB AND THOUGHT THERE WOULD BE A CONFLICT. THIS IS A PROB I BELIEVE WITH TCASII. THE TCASII DID NOT TAKE INTO ACCOUNT THE OTHER ACR, ONLY THE ACFT CLBING BELOW US.

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.