Narrative:

I was working the north en route departure sector on this night. My sector owns FL230 and below north of the houston; tx terminal area (with the exception of the approach control airspace that covers the south side of my sector 15000 ft and below). Air carrier X1 checks on my frequency leaving 14400 ft for 15000 ft. I do not know this aircraft because he is actually switched to my frequency in error by the I90 approach controller. This aircraft should be talking to the wbound en route sector. I do not notice the full call sign or altitude because I am consumed with many of the other details and duties of my sector at the time of his check-in. I am however waiting on the check in of a northbound departure with the call sign of air carrier X2 who is out of approximately 8500 ft at the time of this call. I take normal action to climb air carrier X2 to FL230 at 280 KTS to see if it was him who called. The pilot answers back; 'FL230 and 280 KTS air carrier X1.' as I am listening to his readback; I am also scanning around my sector for my next move or 3 and exactly 4 seconds after hearing his call sign this time with no talking inbtwn; I think something sounded wrong so I say: 'that was air carrier X2 correct?' and get no reply. I then immediately say; 'confirm that call sign climbing to 23000 at 280 KTS was air carrier X2?' the pilot keys up and says; 'uuh; air carrier X1.' I key up and say; 'ok; air carrier X1 disregard my last clearance and identify for me; what were you climbing to previously fifteen?' he responds 'ah yes sir we're up to one five thousand.' I then have confidence that he is still in his original climb profile to 15000 and say; 'ok; maintain one five thousand air carrier X1 calling houston center; you're on the wrong frequency.' I then begin a fast search around the sector to the west of me to see where this aircraft is at. I initiate a 'quick-look' feature which allows me to look at all of the west departure traffic and see the air carrier X1 and can tell he is separated safely from all aircraft. I also notice that he is above the altitude that he told me he was 'we're up to 15000' as the pilot calls me up and says; 'we're out of 16000 for 15000 air carrier X1.' I did not process his last communication but was already in the process of dialing the sector to the west of me to alert them of the encroachment saying; 'hey 80; air carrier X1 took a wrong clearance; he's climbing to twenty three it looks clean is that right?' the other controller confirmed that with me and we felt that we saved this pilot from a very huge error since he read back a clearance for another company aircraft. I then switched the aircraft to the appropriate controller and moved on with working the planes in my sector again. This was a huge distraction for me but I regained my composure; informed my supervisor that I think we just had a pilot deviation and continued to work traffic for the rest of the night. 2 nights later; I was informed that I was being charged with an airspace deviation because our qa department feels that by me saying; 'maintain one five thousand' I gave him a clearance to descend. The fact is that the pilot told me that 'we're up to one five thousand' which means something entirely different in the world of ATC...so I simply restated his previously assigned altitude. Our qa department feels that they have no way of not submitting this as a controller deviation instead of purely as a pilot deviation due to a bad readback at first and then a poorly chosen set of words later. I could not see this aircraft the entire time up until 3 seconds prior to coordinating with the receiving sector 80 just to make sure that life and limb was protected first. Safety was in question and therefore the top priority. I am not educated on nor familiar with the approach control boundaries to the west of my airspace because it is not a normal part of my job duties to know that airspace or the name of the sector working the approach control on that side of houston. Even if I would have known to call him to tell him the air carrier X was descending; I would not have known how to call him or what to call him to get his attention on the shout line. My entire management staff at ZHU to include numerous outside front line mgrs; our qa department and operations mgrs do not have issue with what I did because it was the absolute best choice for this impossible situation. By the time the air carrier X1 tells me his real altitude at the end; he tells me he is out of 16000 ft for 15000 ft which is already in violation of the approach control airspace since he has climbed out of it and now is descending back into it. There was absolutely nothing I could do at any time in order to avoid the airspace deviation.

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Original NASA ASRS Text

Title: ZHU CONTROLLER DESCRIBED SUSPECTED OPERATIONAL DEVIATION EVENT WHEN AIRCRAFT WAS EITHER GIVEN THE WRONG CENTER FREQUENCY AND/OR SWITCHED TO THE INCORRECT FREQUENCY; ALL LEADING TO SUSPECTED AIRSPACE VIOLATION.

Narrative: I WAS WORKING THE N ENRTE DEP SECTOR ON THIS NIGHT. MY SECTOR OWNS FL230 AND BELOW N OF THE HOUSTON; TX TERMINAL AREA (WITH THE EXCEPTION OF THE APCH CTL AIRSPACE THAT COVERS THE S SIDE OF MY SECTOR 15000 FT AND BELOW). ACR X1 CHKS ON MY FREQ LEAVING 14400 FT FOR 15000 FT. I DO NOT KNOW THIS ACFT BECAUSE HE IS ACTUALLY SWITCHED TO MY FREQ IN ERROR BY THE I90 APCH CTLR. THIS ACFT SHOULD BE TALKING TO THE WBOUND ENRTE SECTOR. I DO NOT NOTICE THE FULL CALL SIGN OR ALT BECAUSE I AM CONSUMED WITH MANY OF THE OTHER DETAILS AND DUTIES OF MY SECTOR AT THE TIME OF HIS CHK-IN. I AM HOWEVER WAITING ON THE CHK IN OF A NBOUND DEP WITH THE CALL SIGN OF ACR X2 WHO IS OUT OF APPROX 8500 FT AT THE TIME OF THIS CALL. I TAKE NORMAL ACTION TO CLB ACR X2 TO FL230 AT 280 KTS TO SEE IF IT WAS HIM WHO CALLED. THE PLT ANSWERS BACK; 'FL230 AND 280 KTS ACR X1.' AS I AM LISTENING TO HIS READBACK; I AM ALSO SCANNING AROUND MY SECTOR FOR MY NEXT MOVE OR 3 AND EXACTLY 4 SECONDS AFTER HEARING HIS CALL SIGN THIS TIME WITH NO TALKING INBTWN; I THINK SOMETHING SOUNDED WRONG SO I SAY: 'THAT WAS ACR X2 CORRECT?' AND GET NO REPLY. I THEN IMMEDIATELY SAY; 'CONFIRM THAT CALL SIGN CLBING TO 23000 AT 280 KTS WAS ACR X2?' THE PLT KEYS UP AND SAYS; 'UUH; ACR X1.' I KEY UP AND SAY; 'OK; ACR X1 DISREGARD MY LAST CLRNC AND IDENT FOR ME; WHAT WERE YOU CLBING TO PREVIOUSLY FIFTEEN?' HE RESPONDS 'AH YES SIR WE'RE UP TO ONE FIVE THOUSAND.' I THEN HAVE CONFIDENCE THAT HE IS STILL IN HIS ORIGINAL CLB PROFILE TO 15000 AND SAY; 'OK; MAINTAIN ONE FIVE THOUSAND ACR X1 CALLING HOUSTON CTR; YOU'RE ON THE WRONG FREQ.' I THEN BEGIN A FAST SEARCH AROUND THE SECTOR TO THE W OF ME TO SEE WHERE THIS ACFT IS AT. I INITIATE A 'QUICK-LOOK' FEATURE WHICH ALLOWS ME TO LOOK AT ALL OF THE W DEP TFC AND SEE THE ACR X1 AND CAN TELL HE IS SEPARATED SAFELY FROM ALL ACFT. I ALSO NOTICE THAT HE IS ABOVE THE ALT THAT HE TOLD ME HE WAS 'WE'RE UP TO 15000' AS THE PLT CALLS ME UP AND SAYS; 'WE'RE OUT OF 16000 FOR 15000 ACR X1.' I DID NOT PROCESS HIS LAST COM BUT WAS ALREADY IN THE PROCESS OF DIALING THE SECTOR TO THE W OF ME TO ALERT THEM OF THE ENCROACHMENT SAYING; 'HEY 80; ACR X1 TOOK A WRONG CLRNC; HE'S CLBING TO TWENTY THREE IT LOOKS CLEAN IS THAT RIGHT?' THE OTHER CTLR CONFIRMED THAT WITH ME AND WE FELT THAT WE SAVED THIS PLT FROM A VERY HUGE ERROR SINCE HE READ BACK A CLRNC FOR ANOTHER COMPANY ACFT. I THEN SWITCHED THE ACFT TO THE APPROPRIATE CTLR AND MOVED ON WITH WORKING THE PLANES IN MY SECTOR AGAIN. THIS WAS A HUGE DISTR FOR ME BUT I REGAINED MY COMPOSURE; INFORMED MY SUPVR THAT I THINK WE JUST HAD A PLTDEV AND CONTINUED TO WORK TFC FOR THE REST OF THE NIGHT. 2 NIGHTS LATER; I WAS INFORMED THAT I WAS BEING CHARGED WITH AN AIRSPACE DEV BECAUSE OUR QA DEPT FEELS THAT BY ME SAYING; 'MAINTAIN ONE FIVE THOUSAND' I GAVE HIM A CLRNC TO DSND. THE FACT IS THAT THE PLT TOLD ME THAT 'WE'RE UP TO ONE FIVE THOUSAND' WHICH MEANS SOMETHING ENTIRELY DIFFERENT IN THE WORLD OF ATC...SO I SIMPLY RESTATED HIS PREVIOUSLY ASSIGNED ALT. OUR QA DEPT FEELS THAT THEY HAVE NO WAY OF NOT SUBMITTING THIS AS A CTLR DEV INSTEAD OF PURELY AS A PLTDEV DUE TO A BAD READBACK AT FIRST AND THEN A POORLY CHOSEN SET OF WORDS LATER. I COULD NOT SEE THIS ACFT THE ENTIRE TIME UP UNTIL 3 SECONDS PRIOR TO COORDINATING WITH THE RECEIVING SECTOR 80 JUST TO MAKE SURE THAT LIFE AND LIMB WAS PROTECTED FIRST. SAFETY WAS IN QUESTION AND THEREFORE THE TOP PRIORITY. I AM NOT EDUCATED ON NOR FAMILIAR WITH THE APCH CTL BOUNDARIES TO THE W OF MY AIRSPACE BECAUSE IT IS NOT A NORMAL PART OF MY JOB DUTIES TO KNOW THAT AIRSPACE OR THE NAME OF THE SECTOR WORKING THE APCH CTL ON THAT SIDE OF HOUSTON. EVEN IF I WOULD HAVE KNOWN TO CALL HIM TO TELL HIM THE ACR X WAS DSNDING; I WOULD NOT HAVE KNOWN HOW TO CALL HIM OR WHAT TO CALL HIM TO GET HIS ATTN ON THE SHOUT LINE. MY ENTIRE MGMNT STAFF AT ZHU TO INCLUDE NUMEROUS OUTSIDE FRONT LINE MGRS; OUR QA DEPT AND OPS MGRS DO NOT HAVE ISSUE WITH WHAT I DID BECAUSE IT WAS THE ABSOLUTE BEST CHOICE FOR THIS IMPOSSIBLE SITUATION. BY THE TIME THE ACR X1 TELLS ME HIS REAL ALT AT THE END; HE TELLS ME HE IS OUT OF 16000 FT FOR 15000 FT WHICH IS ALREADY IN VIOLATION OF THE APCH CTL AIRSPACE SINCE HE HAS CLBED OUT OF IT AND NOW IS DSNDING BACK INTO IT. THERE WAS ABSOLUTELY NOTHING I COULD DO AT ANY TIME IN ORDER TO AVOID THE AIRSPACE DEV.

Data retrieved from NASA's ASRS site as of May 2009 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.