Narrative:

Our flight was north of the baq VOR (barranquilla; columbia) traveling northbound on airway UG430 when we were cleared to ascend from FL340 to FL350 by barranquilla north control (124.3). Once level at FL350; the captain of our flight informed barranquilla north control that we had reached FL350. Barranquilla control acknowledged this and advised us to maintain our altitude. Approximately 10 mins later; we heard barranquilla north control clear a sbound aircraft located north of our position to FL350; and to 'report remol intersection;' which is a fix on the same airway we were on; yet located south of our position. Upon hearing this; the captain of our flight queried the ATC controller about whether he wanted us at FL350 or not; since this would obviously cause a conflict with the opposite direction traffic. The barranquilla north controller took a few moments to respond to us; and when he did; he advised us to descend to FL340 due to opposite direction traffic. We expedited our descent to FL340; and a few mins later (10 at the most) we visually observed and confirmed on TCASII the traffic at FL350; about 3 mi west of us. Less than 20 mins later; when we were handed off to kingston center (jamaica); the barranquilla controller advised; 'in the future do not deviate from your assigned altitude unless cleared to do so by a controller.' the captain of our flight responded that we had climbed from FL340 to FL350 only after being cleared by the controller. The barranquilla north controller did not respond to this reply; and we switched to kingston control (128.1). The barranquilla controller must have recognized that it was his mistake which could have caused a more serious traffic conflict at FL350 on the airway. I am certain that we were cleared to FL350. The barranquilla controller even acknowledged our reaching FL350; and advised 'roger; maintain FL350; report kiler.' (kiler is the fir boundary between barranquilla control and kingston center.) I believe that what caused the problem was the controller's seeming inattn to his traffic due to fatigue or a related physiological condition. It is not uncommon to speak to barely awake ATC controllers in the colombian airspace system. Their fatigued voices and occasional confusion make this very apparent. Possible factors include: 1) the controllers being unaccustomed to the rvsm separation minimums which recently went into effect. 2) the barriers in communication between controller and pilot due to language differences; though both were speaking english when being cleared to FL350; and when acknowledging to maintain FL350. 3) a lack of coordination between controllers when switching from one sector of barranquilla center to another. Although there were no resolution or terminal advisories given by the TCASII because both aircraft crossed each other within the criteria specified by rvsm regulations; things could have been much different had we not been listening carefully to the radios. I think it was our level of awareness; due to being unusually well rested at the time; which prevented the situation from becoming something else. Often with nighttime; unscheduled freight operations it is a hard fact that all pilots may be asleep in the cockpit at the same time; even for short moments. A final note: our flight was in radar contact at the time this occurred. I do not think the opposite direction traffic was in radar contact.

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Original NASA ASRS Text

Title: ACR FLT CREW IDENTED POTENTIAL SEPARATION PROB AT FL350 IN COLOMBIAN AIRSPACE; ADVISED ATC AND WAS ISSUED AMENDED ALT.

Narrative: OUR FLT WAS N OF THE BAQ VOR (BARRANQUILLA; COLUMBIA) TRAVELING NBOUND ON AIRWAY UG430 WHEN WE WERE CLRED TO ASCEND FROM FL340 TO FL350 BY BARRANQUILLA N CTL (124.3). ONCE LEVEL AT FL350; THE CAPT OF OUR FLT INFORMED BARRANQUILLA N CTL THAT WE HAD REACHED FL350. BARRANQUILLA CTL ACKNOWLEDGED THIS AND ADVISED US TO MAINTAIN OUR ALT. APPROX 10 MINS LATER; WE HEARD BARRANQUILLA N CTL CLR A SBOUND ACFT LOCATED N OF OUR POS TO FL350; AND TO 'RPT REMOL INTXN;' WHICH IS A FIX ON THE SAME AIRWAY WE WERE ON; YET LOCATED S OF OUR POS. UPON HEARING THIS; THE CAPT OF OUR FLT QUERIED THE ATC CTLR ABOUT WHETHER HE WANTED US AT FL350 OR NOT; SINCE THIS WOULD OBVIOUSLY CAUSE A CONFLICT WITH THE OPPOSITE DIRECTION TFC. THE BARRANQUILLA N CTLR TOOK A FEW MOMENTS TO RESPOND TO US; AND WHEN HE DID; HE ADVISED US TO DSND TO FL340 DUE TO OPPOSITE DIRECTION TFC. WE EXPEDITED OUR DSCNT TO FL340; AND A FEW MINS LATER (10 AT THE MOST) WE VISUALLY OBSERVED AND CONFIRMED ON TCASII THE TFC AT FL350; ABOUT 3 MI W OF US. LESS THAN 20 MINS LATER; WHEN WE WERE HANDED OFF TO KINGSTON CTR (JAMAICA); THE BARRANQUILLA CTLR ADVISED; 'IN THE FUTURE DO NOT DEVIATE FROM YOUR ASSIGNED ALT UNLESS CLRED TO DO SO BY A CTLR.' THE CAPT OF OUR FLT RESPONDED THAT WE HAD CLBED FROM FL340 TO FL350 ONLY AFTER BEING CLRED BY THE CTLR. THE BARRANQUILLA N CTLR DID NOT RESPOND TO THIS REPLY; AND WE SWITCHED TO KINGSTON CTL (128.1). THE BARRANQUILLA CTLR MUST HAVE RECOGNIZED THAT IT WAS HIS MISTAKE WHICH COULD HAVE CAUSED A MORE SERIOUS TFC CONFLICT AT FL350 ON THE AIRWAY. I AM CERTAIN THAT WE WERE CLRED TO FL350. THE BARRANQUILLA CTLR EVEN ACKNOWLEDGED OUR REACHING FL350; AND ADVISED 'ROGER; MAINTAIN FL350; RPT KILER.' (KILER IS THE FIR BOUNDARY BTWN BARRANQUILLA CTL AND KINGSTON CTR.) I BELIEVE THAT WHAT CAUSED THE PROB WAS THE CTLR'S SEEMING INATTN TO HIS TFC DUE TO FATIGUE OR A RELATED PHYSIOLOGICAL CONDITION. IT IS NOT UNCOMMON TO SPEAK TO BARELY AWAKE ATC CTLRS IN THE COLOMBIAN AIRSPACE SYS. THEIR FATIGUED VOICES AND OCCASIONAL CONFUSION MAKE THIS VERY APPARENT. POSSIBLE FACTORS INCLUDE: 1) THE CTLRS BEING UNACCUSTOMED TO THE RVSM SEPARATION MINIMUMS WHICH RECENTLY WENT INTO EFFECT. 2) THE BARRIERS IN COM BTWN CTLR AND PLT DUE TO LANGUAGE DIFFERENCES; THOUGH BOTH WERE SPEAKING ENGLISH WHEN BEING CLRED TO FL350; AND WHEN ACKNOWLEDGING TO MAINTAIN FL350. 3) A LACK OF COORD BTWN CTLRS WHEN SWITCHING FROM ONE SECTOR OF BARRANQUILLA CTR TO ANOTHER. ALTHOUGH THERE WERE NO RESOLUTION OR TERMINAL ADVISORIES GIVEN BY THE TCASII BECAUSE BOTH ACFT CROSSED EACH OTHER WITHIN THE CRITERIA SPECIFIED BY RVSM REGS; THINGS COULD HAVE BEEN MUCH DIFFERENT HAD WE NOT BEEN LISTENING CAREFULLY TO THE RADIOS. I THINK IT WAS OUR LEVEL OF AWARENESS; DUE TO BEING UNUSUALLY WELL RESTED AT THE TIME; WHICH PREVENTED THE SIT FROM BECOMING SOMETHING ELSE. OFTEN WITH NIGHTTIME; UNSCHEDULED FREIGHT OPS IT IS A HARD FACT THAT ALL PLTS MAY BE ASLEEP IN THE COCKPIT AT THE SAME TIME; EVEN FOR SHORT MOMENTS. A FINAL NOTE: OUR FLT WAS IN RADAR CONTACT AT THE TIME THIS OCCURRED. I DO NOT THINK THE OPPOSITE DIRECTION TFC WAS IN RADAR CONTACT.

Data retrieved from NASA's ASRS site as of January 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.