Narrative:

This operational error was caused by an air traffic controller blatantly disregarding control instructions imposed on him by another controller and a NAS computer malfunction. This summary must begin with a brief explanation of the 'guard dog cap.' mins prior to the operational error the guard dog cap (combat air patrol) was deactivated and determined cold. This is important because the LOA's are amended with the status of guard dog cap. All ATC parties involved with guard dog were aware that the cap was cold and original LOA directives were to be adhered to. A discussion over landlines between the potomac approach controller and myself (the ZDC controller) to verify the guard dog status and LOA status was completed prior to the operational error. With normal procedures in place the following operational error developed. Aircraft #1 and #2 filed same routes of flight out of the washington metropolitan area and requested same altitude. Aircraft #1 departed bwi and should have been climbing to FL230, (by LOA). Prior to the xfer of radar identify, I (the ZDC receiving controller) phoned the xferring controller (potomac TRACON) and instructed the controller to stop the climb of aircraft #1 at FL210. At that time aircraft #1 was climbing through FL180. Real time coordination is very common between these 2 sectors and changes like this occur frequently. The potomac controller acknowledged my communication by reading back the instruction and signed off with his initials. Aircraft #2 departs dca airport and is worked by another potomac controller. Aircraft #2 is climbed to 17000 ft via the LOA. Identify/communications xferred to me in time for an uninterrupted climb. I now have received identify xfer on both aircraft #1 and #2 but only communication xfer on aircraft #2 (the dca departure). On initial check in from aircraft #2 I issued a clearance to FL190 remembering that I had just given the potomac controller instructions to climb aircraft #1 to FL210 only. Aircraft #1 should have been in the climb and when I observed aircraft #1's mode C click out of FL190 to FL191, I understand that he is climbing and that is when aircraft #2 is cleared to FL190. I continued to scan my sector and complete other tasks. I noticed that the conflict alert had initiated between aircraft #1 and #2. It did not concern me because aircraft #1 had already vacated FL190 which was aircraft #2's assignment. What did concern me was that communication xfer on aircraft #1 had not been completed yet. As you have figured out by now the potomac controller failed to comply with the instructions imposed on him from me to assign aircraft #1 FL210. He had only assigned aircraft #1 FL190 (which happens to be the procedure for guard dog 'hot'). The potomac controller leveled off aircraft #1 at FL190 and did not climb or xfer communications until the aircraft was over 10 mi inside my airspace. The computer problem which contributed to the error was that while aircraft #1 was level at FL190 the computer showed different and in fact showed FL191 indicating a climb, just like I was expecting. Unfortunately the error was over as quickly as it began due to the altitude assignments so no corrective action could have been performed. Lessons learned: trust no one or nothing. Question everything and question it again. Do not perform your ATC job with the understanding you can rely on others to follow your instructions. Control based on what you know is being accomplished. 'Until you see it -- don't believe it.' I should have waited for aircraft #1's communication xfer prior to assigning aircraft #2 FL190. That would have erased any doubt and in fact would have been the 'legal' way to handle this situation. I have also learned that the FAA still has a long way to go in the area of 'equipment.' erroneous equipment readings, trusting fellow controllers and a departure from the rules of basic altitude assignments led to the operational error.

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Original NASA ASRS Text

Title: ZDC CTLR EXPERIENCED OPERROR AT FL190 WHEN PCT CTLR FAILED TO COMPLY WITH PREVIOUS COORDINATED ALT ASSIGNMENTS.

Narrative: THIS OPERROR WAS CAUSED BY AN AIR TFC CTLR BLATANTLY DISREGARDING CTL INSTRUCTIONS IMPOSED ON HIM BY ANOTHER CTLR AND A NAS COMPUTER MALFUNCTION. THIS SUMMARY MUST BEGIN WITH A BRIEF EXPLANATION OF THE 'GUARD DOG CAP.' MINS PRIOR TO THE OPERROR THE GUARD DOG CAP (COMBAT AIR PATROL) WAS DEACTIVATED AND DETERMINED COLD. THIS IS IMPORTANT BECAUSE THE LOA'S ARE AMENDED WITH THE STATUS OF GUARD DOG CAP. ALL ATC PARTIES INVOLVED WITH GUARD DOG WERE AWARE THAT THE CAP WAS COLD AND ORIGINAL LOA DIRECTIVES WERE TO BE ADHERED TO. A DISCUSSION OVER LANDLINES BTWN THE POTOMAC APCH CTLR AND MYSELF (THE ZDC CTLR) TO VERIFY THE GUARD DOG STATUS AND LOA STATUS WAS COMPLETED PRIOR TO THE OPERROR. WITH NORMAL PROCS IN PLACE THE FOLLOWING OPERROR DEVELOPED. ACFT #1 AND #2 FILED SAME ROUTES OF FLT OUT OF THE WASHINGTON METRO AREA AND REQUESTED SAME ALT. ACFT #1 DEPARTED BWI AND SHOULD HAVE BEEN CLBING TO FL230, (BY LOA). PRIOR TO THE XFER OF RADAR IDENT, I (THE ZDC RECEIVING CTLR) PHONED THE XFERRING CTLR (POTOMAC TRACON) AND INSTRUCTED THE CTLR TO STOP THE CLB OF ACFT #1 AT FL210. AT THAT TIME ACFT #1 WAS CLBING THROUGH FL180. REAL TIME COORD IS VERY COMMON BTWN THESE 2 SECTORS AND CHANGES LIKE THIS OCCUR FREQUENTLY. THE POTOMAC CTLR ACKNOWLEDGED MY COM BY READING BACK THE INSTRUCTION AND SIGNED OFF WITH HIS INITIALS. ACFT #2 DEPARTS DCA ARPT AND IS WORKED BY ANOTHER POTOMAC CTLR. ACFT #2 IS CLBED TO 17000 FT VIA THE LOA. IDENT/COMS XFERRED TO ME IN TIME FOR AN UNINTERRUPTED CLB. I NOW HAVE RECEIVED IDENT XFER ON BOTH ACFT #1 AND #2 BUT ONLY COM XFER ON ACFT #2 (THE DCA DEP). ON INITIAL CHK IN FROM ACFT #2 I ISSUED A CLRNC TO FL190 REMEMBERING THAT I HAD JUST GIVEN THE POTOMAC CTLR INSTRUCTIONS TO CLB ACFT #1 TO FL210 ONLY. ACFT #1 SHOULD HAVE BEEN IN THE CLB AND WHEN I OBSERVED ACFT #1'S MODE C CLICK OUT OF FL190 TO FL191, I UNDERSTAND THAT HE IS CLBING AND THAT IS WHEN ACFT #2 IS CLRED TO FL190. I CONTINUED TO SCAN MY SECTOR AND COMPLETE OTHER TASKS. I NOTICED THAT THE CONFLICT ALERT HAD INITIATED BTWN ACFT #1 AND #2. IT DID NOT CONCERN ME BECAUSE ACFT #1 HAD ALREADY VACATED FL190 WHICH WAS ACFT #2'S ASSIGNMENT. WHAT DID CONCERN ME WAS THAT COM XFER ON ACFT #1 HAD NOT BEEN COMPLETED YET. AS YOU HAVE FIGURED OUT BY NOW THE POTOMAC CTLR FAILED TO COMPLY WITH THE INSTRUCTIONS IMPOSED ON HIM FROM ME TO ASSIGN ACFT #1 FL210. HE HAD ONLY ASSIGNED ACFT #1 FL190 (WHICH HAPPENS TO BE THE PROC FOR GUARD DOG 'HOT'). THE POTOMAC CTLR LEVELED OFF ACFT #1 AT FL190 AND DID NOT CLB OR XFER COMS UNTIL THE ACFT WAS OVER 10 MI INSIDE MY AIRSPACE. THE COMPUTER PROB WHICH CONTRIBUTED TO THE ERROR WAS THAT WHILE ACFT #1 WAS LEVEL AT FL190 THE COMPUTER SHOWED DIFFERENT AND IN FACT SHOWED FL191 INDICATING A CLB, JUST LIKE I WAS EXPECTING. UNFORTUNATELY THE ERROR WAS OVER AS QUICKLY AS IT BEGAN DUE TO THE ALT ASSIGNMENTS SO NO CORRECTIVE ACTION COULD HAVE BEEN PERFORMED. LESSONS LEARNED: TRUST NO ONE OR NOTHING. QUESTION EVERYTHING AND QUESTION IT AGAIN. DO NOT PERFORM YOUR ATC JOB WITH THE UNDERSTANDING YOU CAN RELY ON OTHERS TO FOLLOW YOUR INSTRUCTIONS. CTL BASED ON WHAT YOU KNOW IS BEING ACCOMPLISHED. 'UNTIL YOU SEE IT -- DON'T BELIEVE IT.' I SHOULD HAVE WAITED FOR ACFT #1'S COM XFER PRIOR TO ASSIGNING ACFT #2 FL190. THAT WOULD HAVE ERASED ANY DOUBT AND IN FACT WOULD HAVE BEEN THE 'LEGAL' WAY TO HANDLE THIS SIT. I HAVE ALSO LEARNED THAT THE FAA STILL HAS A LONG WAY TO GO IN THE AREA OF 'EQUIP.' ERRONEOUS EQUIP READINGS, TRUSTING FELLOW CTLRS AND A DEP FROM THE RULES OF BASIC ALT ASSIGNMENTS LED TO THE OPERROR.

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.