Narrative:

Air carrier X flight from las to jfk departed las apr/thu/98, 2 hours late, on a red eye to ny. We leveled off at FL370 and experienced light chop so we decided to block FL370 to FL390. After trying different altitudes we leveled off at FL390. Later in the flight we climbed to find a better ride when center asked our altitude. Then it occurred to us we were block from FL370 to FL390 instead of FL390 to FL410. The controller realized what we did and asked if we wanted to block FL390 to FL410. We elected to maintain FL410 instead of a block altitude. The controller said there was no problem and gave us FL410.

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Original NASA ASRS Text

Title: FLC OF A B757 CLBED ABOVE ASSIGNED CRUISING ALT TO FIND SMOOTHER AIR NOT REALIZING THAT THEY HAD NOT BEEN ASSIGNED A HIGHER 'BLOCK OF ALTS' BY ARTCC RADAR CTLR. WHEN ATC QUESTIONED THEIR ALT THEY REALIZED THAT THEY HAD DEVIATED FROM THEIR CLRNC. CTLR THEN ASSIGNED THEM THE HIGHER ALTS AND SAID THAT THERE HAD BEEN NO CONFLICT.

Narrative: ACR X FLT FROM LAS TO JFK DEPARTED LAS APR/THU/98, 2 HRS LATE, ON A RED EYE TO NY. WE LEVELED OFF AT FL370 AND EXPERIENCED LIGHT CHOP SO WE DECIDED TO BLOCK FL370 TO FL390. AFTER TRYING DIFFERENT ALTS WE LEVELED OFF AT FL390. LATER IN THE FLT WE CLBED TO FIND A BETTER RIDE WHEN CTR ASKED OUR ALT. THEN IT OCCURRED TO US WE WERE BLOCK FROM FL370 TO FL390 INSTEAD OF FL390 TO FL410. THE CTLR REALIZED WHAT WE DID AND ASKED IF WE WANTED TO BLOCK FL390 TO FL410. WE ELECTED TO MAINTAIN FL410 INSTEAD OF A BLOCK ALT. THE CTLR SAID THERE WAS NO PROB AND GAVE US FL410.

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.