Narrative:

We received a message from ZLA that we had been involved in a potential pilot deviation because of a loss of separation during our time with ZAB and that they requested we call when we got on the ground. My first officer and I surmised that the only potential conflict was on climb out when we received a time restr climb to FL350 from FL310. The controller queried our ascent time to FL350 and upon our concurrence, the first officer replied that we could be level in 2 mins. The controller responded with a clearance to be level at FL350 and gave us a zulu time and followed that up with the current center time. The first officer replied 'to be at FL350 in 2 mins or less.' at which time he placed his clock in 'et' mode and began the count up, as per our sops, and I noted the time indication on my clock in order to reference the 2 mins as well. I made a mental note that my clock was off slightly from center time and needed to be reset, which I would do later in-flight. I initiated a climb, which resulted in a climb rate well in access of 3000 FPM. Then out of 34000 ft, I began reducing the climb rate to 1000 FPM, also in accordance with our SOP. I initiated the leveloff phase at 34700 ft, which was the last time I referenced the first officer's clock and it indicated 1 hour 50 mins. At about the same time my first officer spotted traffic at our 10 O'clock position, 2000 ft below us and about 4-5 mi, and we heard a transmission with our call sign, something garbled, and then cut off in mid phrase. A few mins later we received a frequency change. We never received any traffic information or any indication that there had been a loss of separation. I feel, if there would have been any potential for separation loss, we should have received a traffic alert, an inquiry as to our climb status, or at least after the fact, some notification from that controller or supervisor, not 30 mins later from another center all together. In retrospect, since this clearance restr was such a short time span, there was a potential for conflicting information. I don't feel it is logical to give short time span clrncs in reference to specific times. Since clocks are set differently this leads to confusing time restrs and possible asking pilots to reset clocks during a critical phase of flight. So we revert to the more manageable value, 2 mins, which will be the same everywhere. The only problem I see now is when does the time start. Our SOP starts the time after unkeying the microphone from accepting the clearance, but what does the controller expect? Either way, on short time restr clearance this can lead to several seconds of climb time and several hundred ft in altitude. If we had had more information, that the controller felt there was a possible loss of separation, ie, a traffic alert, traffic information on initial clearance, or maybe a TCASII requirement, this would have increased our situational awareness and I could have briefed a deviation from our climb SOP, requested a turn, or something else. As it turns out, I still feel we met the requirement of the clearance and our SOP.

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Original NASA ASRS Text

Title: ENRTE LR24 EXPERIENCE POSSIBLE LOSS OF SEPARATION IN ZAB AIRSPACE.

Narrative: WE RECEIVED A MESSAGE FROM ZLA THAT WE HAD BEEN INVOLVED IN A POTENTIAL PLTDEV BECAUSE OF A LOSS OF SEPARATION DURING OUR TIME WITH ZAB AND THAT THEY REQUESTED WE CALL WHEN WE GOT ON THE GND. MY FO AND I SURMISED THAT THE ONLY POTENTIAL CONFLICT WAS ON CLBOUT WHEN WE RECEIVED A TIME RESTR CLB TO FL350 FROM FL310. THE CTLR QUERIED OUR ASCENT TIME TO FL350 AND UPON OUR CONCURRENCE, THE FO REPLIED THAT WE COULD BE LEVEL IN 2 MINS. THE CTLR RESPONDED WITH A CLRNC TO BE LEVEL AT FL350 AND GAVE US A ZULU TIME AND FOLLOWED THAT UP WITH THE CURRENT CTR TIME. THE FO REPLIED 'TO BE AT FL350 IN 2 MINS OR LESS.' AT WHICH TIME HE PLACED HIS CLOCK IN 'ET' MODE AND BEGAN THE COUNT UP, AS PER OUR SOPS, AND I NOTED THE TIME INDICATION ON MY CLOCK IN ORDER TO REF THE 2 MINS AS WELL. I MADE A MENTAL NOTE THAT MY CLOCK WAS OFF SLIGHTLY FROM CTR TIME AND NEEDED TO BE RESET, WHICH I WOULD DO LATER INFLT. I INITIATED A CLB, WHICH RESULTED IN A CLB RATE WELL IN ACCESS OF 3000 FPM. THEN OUT OF 34000 FT, I BEGAN REDUCING THE CLB RATE TO 1000 FPM, ALSO IN ACCORDANCE WITH OUR SOP. I INITIATED THE LEVELOFF PHASE AT 34700 FT, WHICH WAS THE LAST TIME I REFED THE FO'S CLOCK AND IT INDICATED 1 HR 50 MINS. AT ABOUT THE SAME TIME MY FO SPOTTED TFC AT OUR 10 O'CLOCK POS, 2000 FT BELOW US AND ABOUT 4-5 MI, AND WE HEARD A XMISSION WITH OUR CALL SIGN, SOMETHING GARBLED, AND THEN CUT OFF IN MID PHRASE. A FEW MINS LATER WE RECEIVED A FREQ CHANGE. WE NEVER RECEIVED ANY TFC INFO OR ANY INDICATION THAT THERE HAD BEEN A LOSS OF SEPARATION. I FEEL, IF THERE WOULD HAVE BEEN ANY POTENTIAL FOR SEPARATION LOSS, WE SHOULD HAVE RECEIVED A TFC ALERT, AN INQUIRY AS TO OUR CLB STATUS, OR AT LEAST AFTER THE FACT, SOME NOTIFICATION FROM THAT CTLR OR SUPVR, NOT 30 MINS LATER FROM ANOTHER CTR ALL TOGETHER. IN RETROSPECT, SINCE THIS CLRNC RESTR WAS SUCH A SHORT TIME SPAN, THERE WAS A POTENTIAL FOR CONFLICTING INFO. I DON'T FEEL IT IS LOGICAL TO GIVE SHORT TIME SPAN CLRNCS IN REF TO SPECIFIC TIMES. SINCE CLOCKS ARE SET DIFFERENTLY THIS LEADS TO CONFUSING TIME RESTRS AND POSSIBLE ASKING PLTS TO RESET CLOCKS DURING A CRITICAL PHASE OF FLT. SO WE REVERT TO THE MORE MANAGEABLE VALUE, 2 MINS, WHICH WILL BE THE SAME EVERYWHERE. THE ONLY PROB I SEE NOW IS WHEN DOES THE TIME START. OUR SOP STARTS THE TIME AFTER UNKEYING THE MIKE FROM ACCEPTING THE CLRNC, BUT WHAT DOES THE CTLR EXPECT? EITHER WAY, ON SHORT TIME RESTR CLRNC THIS CAN LEAD TO SEVERAL SECONDS OF CLB TIME AND SEVERAL HUNDRED FT IN ALT. IF WE HAD HAD MORE INFO, THAT THE CTLR FELT THERE WAS A POSSIBLE LOSS OF SEPARATION, IE, A TFC ALERT, TFC INFO ON INITIAL CLRNC, OR MAYBE A TCASII REQUIREMENT, THIS WOULD HAVE INCREASED OUR SITUATIONAL AWARENESS AND I COULD HAVE BRIEFED A DEV FROM OUR CLB SOP, REQUESTED A TURN, OR SOMETHING ELSE. AS IT TURNS OUT, I STILL FEEL WE MET THE REQUIREMENT OF THE CLRNC AND OUR SOP.

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.