Narrative:

At approximately XA58Z, we were switched to ZBW on frequency 124.52. We were aircraft #1 atl/zrh on dec/xa/98 between rbv VORTAC and yahoo intersection. We had trouble getting checked in on the frequency due to controller handling too many frequencys and calls to a large number of aircraft. At XB00Z, we received and responded to a TCASII RA and immediately turned left and climbed as directed by the RA, leveled off at FL336. Conflicting traffic was aircraft #2 at FL330. He also received a TCASII RA. Supplemental information from acn 422090: I was the relief pilot on a B767ER en route from atl to zurich. I was on break. I felt the aircraft climb and then several seconds later descend. After completing my break, I returned to the cockpit and was told by the captain and the other first officer they had responded to a TCASII RA while at FL330. Supplemental information from acn 422080: the system engineer advised us mins before this error that we were to transition to our radar backup system. This system locked up and prevented me from moving data blocks, making inputs, or taking/giving handoffs. Also, we had 3 sectors combined with 14 aircraft on frequency and we had 2 frequencys on, when normally there is only 1. The 2 aircraft involved advised me that they were taking action due to TCASII alert. Supplemental information from acn 422689: aircraft #1 was IFR over rbv toward ack. Aircraft #2 was nebound on J174 toward hto. At approximately XA15Z, the system engineer came through the control room and announced we needed to go the backup system darc. We transitioned to darc and shortly afterwards, we received an electronic message at the d-pos that darc is disabled. We questioned which system to use. We then completely lost the NAS computer and the radar side buttons were disabled/intermittent. The d-side buttons did not work in darc at all during the confusion of: 1) still working airplane, 2) not knowing which system to use, 3) problems with the system we were using, 4) conflict alert is not active in darc. Aircraft #1 and aircraft #2 were merging and TCASII took over.

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Original NASA ASRS Text

Title: ACR B767 FLC INITIATES TCASII RA CLB FOR AN ACR L1011 CONFLICTING AT SAME ALT. ZBW CTLRS EXPERIENCING RADAR FAILURE EQUIP PROBS AND DO NOT OBSERVE THE POTENTIAL CONFLICT.

Narrative: AT APPROX XA58Z, WE WERE SWITCHED TO ZBW ON FREQ 124.52. WE WERE ACFT #1 ATL/ZRH ON DEC/XA/98 BTWN RBV VORTAC AND YAHOO INTXN. WE HAD TROUBLE GETTING CHKED IN ON THE FREQ DUE TO CTLR HANDLING TOO MANY FREQS AND CALLS TO A LARGE NUMBER OF ACFT. AT XB00Z, WE RECEIVED AND RESPONDED TO A TCASII RA AND IMMEDIATELY TURNED L AND CLBED AS DIRECTED BY THE RA, LEVELED OFF AT FL336. CONFLICTING TFC WAS ACFT #2 AT FL330. HE ALSO RECEIVED A TCASII RA. SUPPLEMENTAL INFO FROM ACN 422090: I WAS THE RELIEF PLT ON A B767ER ENRTE FROM ATL TO ZURICH. I WAS ON BREAK. I FELT THE ACFT CLB AND THEN SEVERAL SECONDS LATER DSND. AFTER COMPLETING MY BREAK, I RETURNED TO THE COCKPIT AND WAS TOLD BY THE CAPT AND THE OTHER FO THEY HAD RESPONDED TO A TCASII RA WHILE AT FL330. SUPPLEMENTAL INFO FROM ACN 422080: THE SYS ENGINEER ADVISED US MINS BEFORE THIS ERROR THAT WE WERE TO TRANSITION TO OUR RADAR BACKUP SYS. THIS SYS LOCKED UP AND PREVENTED ME FROM MOVING DATA BLOCKS, MAKING INPUTS, OR TAKING/GIVING HDOFS. ALSO, WE HAD 3 SECTORS COMBINED WITH 14 ACFT ON FREQ AND WE HAD 2 FREQS ON, WHEN NORMALLY THERE IS ONLY 1. THE 2 ACFT INVOLVED ADVISED ME THAT THEY WERE TAKING ACTION DUE TO TCASII ALERT. SUPPLEMENTAL INFO FROM ACN 422689: ACFT #1 WAS IFR OVER RBV TOWARD ACK. ACFT #2 WAS NEBOUND ON J174 TOWARD HTO. AT APPROX XA15Z, THE SYS ENGINEER CAME THROUGH THE CTL ROOM AND ANNOUNCED WE NEEDED TO GO THE BACKUP SYS DARC. WE TRANSITIONED TO DARC AND SHORTLY AFTERWARDS, WE RECEIVED AN ELECTRONIC MESSAGE AT THE D-POS THAT DARC IS DISABLED. WE QUESTIONED WHICH SYS TO USE. WE THEN COMPLETELY LOST THE NAS COMPUTER AND THE RADAR SIDE BUTTONS WERE DISABLED/INTERMITTENT. THE D-SIDE BUTTONS DID NOT WORK IN DARC AT ALL DURING THE CONFUSION OF: 1) STILL WORKING AIRPLANE, 2) NOT KNOWING WHICH SYS TO USE, 3) PROBS WITH THE SYS WE WERE USING, 4) CONFLICT ALERT IS NOT ACTIVE IN DARC. ACFT #1 AND ACFT #2 WERE MERGING AND TCASII TOOK OVER.

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.