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ZHU radar and associate controllers noted a potential conflict on oceanic traffic crossing a fix in their airspace and coming from mmty ARTCC's airspace. Interfacility coordination was attempted to correct the situation and 1 air carrier was late in making the frequency change. Air carrier (Y) a B737 was descended through the altitude of air carrier (X) an A320 with less than standard separation non radar separation, but did have legal separation when they were radar idented a few mins later.
| Attributes | |
| ACN | 375641 |
| Time | |
| Date | 199707 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : vuh |
| State Reference | TX |
| Altitude | msl bound lower : 33000 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zhu |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Route In Use | enroute : other oceanic enroute airway : zhu enroute airway : mmty |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | enroute : other oceanic |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : flight data |
| Qualification | controller : radar |
| Experience | controller non radar : 9 controller radar : 9 |
| ASRS Report | 375641 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 90000 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Air carrier X and air carrier Y in gulf of mexico non radar sector. Air carrier X an A320/right from MMMX to iad via A552 was coordinated at FL330 mahee estimated XA40Z. A limited data block was observed at FL350 over clonn at XA22Z. Both right and D sides initiated numerous calls to mmty center trying to verify position and altitude of air carrier X. They advised air carrier X should be in communication with us. Air carrier Y a B737 reported on from m2b2 to iah via VB753 mahee estimated XA42Z at FL350. The radar controller expedited air carrier Y from FL350 to FL310 report leaving FL330. Then the mmty controller calls back and advises they have relayed to air carrier X and we observe the limited at FL350 descending to FL310. We went back to air carrier Y and requested a report reaching FL310. Air carrier X finally checked on frequency at FL330. By this time the planes were approximately 40 mi from mahee with air carrier Y still non radar. Targets were radar idented within 10 mi of mahee with air carrier X at FL330 and air carrier Y at FL310. As the targets merged at mahee if no corrective action had been taken this would have been a midair.
Original NASA ASRS Text
Title: ZHU RADAR AND ASSOCIATE CTLRS NOTED A POTENTIAL CONFLICT ON OCEANIC TFC XING A FIX IN THEIR AIRSPACE AND COMING FROM MMTY ARTCC'S AIRSPACE. INTERFAC COORD WAS ATTEMPTED TO CORRECT THE SIT AND 1 ACR WAS LATE IN MAKING THE FREQ CHANGE. ACR (Y) A B737 WAS DSNDED THROUGH THE ALT OF ACR (X) AN A320 WITH LTSS NON RADAR SEPARATION, BUT DID HAVE LEGAL SEPARATION WHEN THEY WERE RADAR IDENTED A FEW MINS LATER.
Narrative: ACR X AND ACR Y IN GULF OF MEXICO NON RADAR SECTOR. ACR X AN A320/R FROM MMMX TO IAD VIA A552 WAS COORDINATED AT FL330 MAHEE ESTIMATED XA40Z. A LIMITED DATA BLOCK WAS OBSERVED AT FL350 OVER CLONN AT XA22Z. BOTH R AND D SIDES INITIATED NUMEROUS CALLS TO MMTY CTR TRYING TO VERIFY POS AND ALT OF ACR X. THEY ADVISED ACR X SHOULD BE IN COM WITH US. ACR Y A B737 RPTED ON FROM M2B2 TO IAH VIA VB753 MAHEE ESTIMATED XA42Z AT FL350. THE RADAR CTLR EXPEDITED ACR Y FROM FL350 TO FL310 RPT LEAVING FL330. THEN THE MMTY CTLR CALLS BACK AND ADVISES THEY HAVE RELAYED TO ACR X AND WE OBSERVE THE LIMITED AT FL350 DSNDING TO FL310. WE WENT BACK TO ACR Y AND REQUESTED A RPT REACHING FL310. ACR X FINALLY CHKED ON FREQ AT FL330. BY THIS TIME THE PLANES WERE APPROX 40 MI FROM MAHEE WITH ACR Y STILL NON RADAR. TARGETS WERE RADAR IDENTED WITHIN 10 MI OF MAHEE WITH ACR X AT FL330 AND ACR Y AT FL310. AS THE TARGETS MERGED AT MAHEE IF NO CORRECTIVE ACTION HAD BEEN TAKEN THIS WOULD HAVE BEEN A MIDAIR.
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.