Narrative:

Widebody transport X at FL350 deviating for WX. Large transport Y climbing to FL350 in conflict. I called the sector adjacent to me and provided a pointout widebody transport X and advised I was unable to accept large transport Y climbing to FL350, so we mutually agreed to stop large transport Y at FL330. The widebody transport X then requested FL310 because of turbulence. I called the adjacent sector and coordinated widebody transport X descending to FL310 and to climb large transport Y to FL350. I then coordinated a pointout widebody transport X to the sector below, since FL350 is my base altitude. Clearance was issued to widebody transport X to 'descend and maintain FL310, no delay in the descent'. Widebody transport X complied, and reached FL310 quickly. I then initiated a pointout to the low sector below the adjacent sector previously mentioned who was still working large transport Y. He responded, 'ok, I've got large transport Y heading 155 degree, should I leave him on that?' I said, 'you can turn him back', thinking since he said 'ok' and saw widebody transport X he would provide separation. Instead, he cleared the aircraft on course, and switched frequency without providing positive separation from known traffic. As I watched large transport Y climb and turn into widebody transport X, I was not concerned. Widebody transport X had been level at FL310 for several mi, and large transport Y was climbing through FL327, at about 500 FPM. Then I noticed large transport Y seemed to level off at FL328. I was still confident that the lower adjacent sector was providing separation, since large transport Y never did report on my frequency. Large transport Y was level at FL328, then went to FL327 in close proximity to widebody transport X. When I called large transport Y he was indeed on my frequency, but had not checked on. I asked the pilot 'did you at any time stop your climb for any reason'? The pilot replied, 'we leveled off to accelerate back there, but we're climbing now'. I feel, if anything, this is a pilot deviation. I cannot believe that a pilot can just level off at will, without advising ATC, not to mention descending 100 ft. Also, I feel the low adjacent sector controller was obligated to provide separation from known traffic.

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Original NASA ASRS Text

Title: LGT CLBING TO FL330 LEVELED OFF 300 FT LOW TO PICK UP SPD AND CAUSED A LTSS INCIDENT WITH A WDB BELOW HIM.

Narrative: WDB X AT FL350 DEVIATING FOR WX. LGT Y CLBING TO FL350 IN CONFLICT. I CALLED THE SECTOR ADJACENT TO ME AND PROVIDED A POINTOUT WDB X AND ADVISED I WAS UNABLE TO ACCEPT LGT Y CLBING TO FL350, SO WE MUTUALLY AGREED TO STOP LGT Y AT FL330. THE WDB X THEN REQUESTED FL310 BECAUSE OF TURB. I CALLED THE ADJACENT SECTOR AND COORDINATED WDB X DSNDING TO FL310 AND TO CLB LGT Y TO FL350. I THEN COORDINATED A POINTOUT WDB X TO THE SECTOR BELOW, SINCE FL350 IS MY BASE ALT. CLRNC WAS ISSUED TO WDB X TO 'DSND AND MAINTAIN FL310, NO DELAY IN THE DSNT'. WDB X COMPLIED, AND REACHED FL310 QUICKLY. I THEN INITIATED A POINTOUT TO THE LOW SECTOR BELOW THE ADJACENT SECTOR PREVIOUSLY MENTIONED WHO WAS STILL WORKING LGT Y. HE RESPONDED, 'OK, I'VE GOT LGT Y HDG 155 DEG, SHOULD I LEAVE HIM ON THAT?' I SAID, 'YOU CAN TURN HIM BACK', THINKING SINCE HE SAID 'OK' AND SAW WDB X HE WOULD PROVIDE SEPARATION. INSTEAD, HE CLRED THE ACFT ON COURSE, AND SWITCHED FREQ WITHOUT PROVIDING POSITIVE SEPARATION FROM KNOWN TFC. AS I WATCHED LGT Y CLB AND TURN INTO WDB X, I WAS NOT CONCERNED. WDB X HAD BEEN LEVEL AT FL310 FOR SEVERAL MI, AND LGT Y WAS CLBING THROUGH FL327, AT ABOUT 500 FPM. THEN I NOTICED LGT Y SEEMED TO LEVEL OFF AT FL328. I WAS STILL CONFIDENT THAT THE LOWER ADJACENT SECTOR WAS PROVIDING SEPARATION, SINCE LGT Y NEVER DID RPT ON MY FREQ. LGT Y WAS LEVEL AT FL328, THEN WENT TO FL327 IN CLOSE PROX TO WDB X. WHEN I CALLED LGT Y HE WAS INDEED ON MY FREQ, BUT HAD NOT CHKED ON. I ASKED THE PLT 'DID YOU AT ANY TIME STOP YOUR CLB FOR ANY REASON'? THE PLT REPLIED, 'WE LEVELED OFF TO ACCELERATE BACK THERE, BUT WE'RE CLBING NOW'. I FEEL, IF ANYTHING, THIS IS A PLTDEV. I CANNOT BELIEVE THAT A PLT CAN JUST LEVEL OFF AT WILL, WITHOUT ADVISING ATC, NOT TO MENTION DSNDING 100 FT. ALSO, I FEEL THE LOW ADJACENT SECTOR CTLR WAS OBLIGATED TO PROVIDE SEPARATION FROM KNOWN TFC.

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.