Narrative:

I was the low altitude controller working air carrier X inbound to mia from england. Air carrier Y climbing out from mia to curacao. Upon realizing the conflict, I issued descent to fl 200 (amended from descent to 16000 ft) to X -- no response. Issued Y climb to fl 190 (amended from climb to FL230). Issued descent to FL200 and heading 180 degrees (70 degrees left) to X. Reads back þhdg 190 degrees and do we have traffic below us?' I acknowledged and advised maintain FL200 and fly heading 180 degrees. X's mode C indicates still descending through FL200, so I turn air carrier Y 35 degrees left (heading 090 degrees). Y advises 'traffic in sight.' after lateral separation is established, X is at FL180 descending to 16000 ft. I asked if he heard me clear him to fl 200? Negative. After being relieved due to loss of separation (3.25 NM and 100 ft) I felt that X was utilizing TCASII information because of his verbal and X's performance response. He never advised me of responding to a TCASII RA. We talked to the pilot after landing and he advised that he was indeed responding to a descend RA of 2200 FPM or greater. I support TCASII as a collision avoidance tool, but by not advising of RA maneuvering, controllers will utilize extreme control actions to try and prevent collision. This may lead to 'losing control' of other portions of their sector. I also feel for the pilot. During an RA, he/they are trying to acquire the TCASII traffic, respond to and perform the RA maneuver, fly the aircraft, communication with ATC. The workload is significant. I think, in this case, he 'forgot' to advise me of the RA and didn't 'hear' FL200 (3 times) because of the workload and fatigue (england to mia). Supplemental information from acn 279191: X, while descending to 16000 ft going direct to junior at 8000 ft, we received TCASII RA alert. TCASII directed us to descend at 2000 FPM. We were already descending at 2200 FPM from mia approach. Mia approach then cleared us to turn left to a 180 degree heading for traffic. We turned to a 180 heading and the TCASII reported we were clear of traffic. We continued descent and reported we were clear of traffic. We continued descent to 16000 ft. Mia approach then asked if we heard a clearance to level at FL200. We advised mia approach. He advised me they checked the approach control recording tape and it showed we never acknowledged a clearance to level at FL200. Supplemental information from acn 279190: X, while descending into mia cleared to 16000 ft we received a TCASII TA followed by an RA to monitor vertical speed not less than 2000 FPM. We were already descending at 2200 FPM. The controller gave us a left turn to 180 degrees and asked why we did not level at FL200 as requested. We did not receive or acknowledge this clearance. We also did not see the other aircraft. On the TCASII screen -- on 40 NM range, the target looked to be within 1 mi. The first officer was not in his seat at the time. I was the io on this trip.

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Original NASA ASRS Text

Title: ACR X TCASII RA WITH Y NON ADHERENCE TO ATC CLRNC HAD LTSS FROM Y. SYS ERROR.

Narrative: I WAS THE LOW ALT CTLR WORKING ACR X INBOUND TO MIA FROM ENGLAND. ACR Y CLBING OUT FROM MIA TO CURACAO. UPON REALIZING THE CONFLICT, I ISSUED DSCNT TO FL 200 (AMENDED FROM DSCNT TO 16000 FT) TO X -- NO RESPONSE. ISSUED Y CLB TO FL 190 (AMENDED FROM CLB TO FL230). ISSUED DSCNT TO FL200 AND HDG 180 DEGS (70 DEGS L) TO X. READS BACK þHDG 190 DEGS AND DO WE HAVE TFC BELOW US?' I ACKNOWLEDGED AND ADVISED MAINTAIN FL200 AND FLY HDG 180 DEGS. X'S MODE C INDICATES STILL DSNDING THROUGH FL200, SO I TURN ACR Y 35 DEGS L (HDG 090 DEGS). Y ADVISES 'TFC IN SIGHT.' AFTER LATERAL SEPARATION IS ESTABLISHED, X IS AT FL180 DSNDING TO 16000 FT. I ASKED IF HE HEARD ME CLR HIM TO FL 200? NEGATIVE. AFTER BEING RELIEVED DUE TO LOSS OF SEPARATION (3.25 NM AND 100 FT) I FELT THAT X WAS UTILIZING TCASII INFO BECAUSE OF HIS VERBAL AND X'S PERFORMANCE RESPONSE. HE NEVER ADVISED ME OF RESPONDING TO A TCASII RA. WE TALKED TO THE PLT AFTER LNDG AND HE ADVISED THAT HE WAS INDEED RESPONDING TO A DSND RA OF 2200 FPM OR GREATER. I SUPPORT TCASII AS A COLLISION AVOIDANCE TOOL, BUT BY NOT ADVISING OF RA MANEUVERING, CTLRS WILL UTILIZE EXTREME CTL ACTIONS TO TRY AND PREVENT COLLISION. THIS MAY LEAD TO 'LOSING CTL' OF OTHER PORTIONS OF THEIR SECTOR. I ALSO FEEL FOR THE PLT. DURING AN RA, HE/THEY ARE TRYING TO ACQUIRE THE TCASII TFC, RESPOND TO AND PERFORM THE RA MANEUVER, FLY THE ACFT, COM WITH ATC. THE WORKLOAD IS SIGNIFICANT. I THINK, IN THIS CASE, HE 'FORGOT' TO ADVISE ME OF THE RA AND DIDN'T 'HEAR' FL200 (3 TIMES) BECAUSE OF THE WORKLOAD AND FATIGUE (ENGLAND TO MIA). SUPPLEMENTAL INFO FROM ACN 279191: X, WHILE DSNDING TO 16000 FT GOING DIRECT TO JUNIOR AT 8000 FT, WE RECEIVED TCASII RA ALERT. TCASII DIRECTED US TO DSND AT 2000 FPM. WE WERE ALREADY DSNDING AT 2200 FPM FROM MIA APCH. MIA APCH THEN CLRED US TO TURN L TO A 180 DEG HDG FOR TFC. WE TURNED TO A 180 HDG AND THE TCASII RPTED WE WERE CLR OF TFC. WE CONTINUED DSCNT AND RPTED WE WERE CLR OF TFC. WE CONTINUED DSCNT TO 16000 FT. MIA APCH THEN ASKED IF WE HEARD A CLRNC TO LEVEL AT FL200. WE ADVISED MIA APCH. HE ADVISED ME THEY CHKED THE APCH CTL RECORDING TAPE AND IT SHOWED WE NEVER ACKNOWLEDGED A CLRNC TO LEVEL AT FL200. SUPPLEMENTAL INFO FROM ACN 279190: X, WHILE DSNDING INTO MIA CLRED TO 16000 FT WE RECEIVED A TCASII TA FOLLOWED BY AN RA TO MONITOR VERT SPD NOT LESS THAN 2000 FPM. WE WERE ALREADY DSNDING AT 2200 FPM. THE CTLR GAVE US A L TURN TO 180 DEGS AND ASKED WHY WE DID NOT LEVEL AT FL200 AS REQUESTED. WE DID NOT RECEIVE OR ACKNOWLEDGE THIS CLRNC. WE ALSO DID NOT SEE THE OTHER ACFT. ON THE TCASII SCREEN -- ON 40 NM RANGE, THE TARGET LOOKED TO BE WITHIN 1 MI. THE FO WAS NOT IN HIS SEAT AT THE TIME. I WAS THE IO ON THIS TRIP.

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.