Narrative:

We were cleared at FL310 and were climbing through FL293 when center called and said to descend and maintain FL290 at the next controller's request. I made a smooth transition and started back down to FL290, but not before reaching FL295. The controller also stated for us to descend to FL290 'whenever we could get pointed back down.' I assumed he meant we could switch from our climb to descent in a reasonable time. I was slightly uncomfortable with the fact that I went to FL295 though. The controller never said a word and we leveled at FL290 where we were soon turned over to the next controller. I don't think there was any problem and we had been cleared up to FL310 before being asked to descend back down. At the same time, I find this happening more and more where controllers amend altitude assignments as we are passing the altitude they want to change us to, or we are already above an altitude when they amend our clearance and expect us to stop our climb immediately. This controller appeared to be giving us room to arrest our climb and start back down, by the way he worded our clearance. He also said to descend and maintain FL290 indicating he knew we were already higher. Also, I cannot remember if it was FL310 or FL330 we were originally cleared to, before being asked to descend to FL290. It does not matter though because we were cleared above FL290 either way, before the amended clearance. This sort of last min clearance change has happened to me at least 3 times in the last month.. In all cases, we were already cleared to a higher altitude when the controller either asked us to descend back down or asked us to maintain an altitude we were already above. Is this just a case of controllers just realizing a possible conflict at the last min, or maybe it is just the fact that there is more and more aircraft in flight levels? Thanks for the reporting form.

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Original NASA ASRS Text

Title: ZLA CTLR AMENDS CLB ALT OF LJ35 AND RPTR WONDERS WHY.

Narrative: WE WERE CLRED AT FL310 AND WERE CLBING THROUGH FL293 WHEN CTR CALLED AND SAID TO DSND AND MAINTAIN FL290 AT THE NEXT CTLR'S REQUEST. I MADE A SMOOTH TRANSITION AND STARTED BACK DOWN TO FL290, BUT NOT BEFORE REACHING FL295. THE CTLR ALSO STATED FOR US TO DSND TO FL290 'WHENEVER WE COULD GET POINTED BACK DOWN.' I ASSUMED HE MEANT WE COULD SWITCH FROM OUR CLB TO DSCNT IN A REASONABLE TIME. I WAS SLIGHTLY UNCOMFORTABLE WITH THE FACT THAT I WENT TO FL295 THOUGH. THE CTLR NEVER SAID A WORD AND WE LEVELED AT FL290 WHERE WE WERE SOON TURNED OVER TO THE NEXT CTLR. I DON'T THINK THERE WAS ANY PROB AND WE HAD BEEN CLRED UP TO FL310 BEFORE BEING ASKED TO DSND BACK DOWN. AT THE SAME TIME, I FIND THIS HAPPENING MORE AND MORE WHERE CTLRS AMEND ALT ASSIGNMENTS AS WE ARE PASSING THE ALT THEY WANT TO CHANGE US TO, OR WE ARE ALREADY ABOVE AN ALT WHEN THEY AMEND OUR CLRNC AND EXPECT US TO STOP OUR CLB IMMEDIATELY. THIS CTLR APPEARED TO BE GIVING US ROOM TO ARREST OUR CLB AND START BACK DOWN, BY THE WAY HE WORDED OUR CLRNC. HE ALSO SAID TO DSND AND MAINTAIN FL290 INDICATING HE KNEW WE WERE ALREADY HIGHER. ALSO, I CANNOT REMEMBER IF IT WAS FL310 OR FL330 WE WERE ORIGINALLY CLRED TO, BEFORE BEING ASKED TO DSND TO FL290. IT DOES NOT MATTER THOUGH BECAUSE WE WERE CLRED ABOVE FL290 EITHER WAY, BEFORE THE AMENDED CLRNC. THIS SORT OF LAST MIN CLRNC CHANGE HAS HAPPENED TO ME AT LEAST 3 TIMES IN THE LAST MONTH.. IN ALL CASES, WE WERE ALREADY CLRED TO A HIGHER ALT WHEN THE CTLR EITHER ASKED US TO DSND BACK DOWN OR ASKED US TO MAINTAIN AN ALT WE WERE ALREADY ABOVE. IS THIS JUST A CASE OF CTLRS JUST REALIZING A POSSIBLE CONFLICT AT THE LAST MIN, OR MAYBE IT IS JUST THE FACT THAT THERE IS MORE AND MORE ACFT IN FLT LEVELS? THANKS FOR THE RPTING FORM.

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.