Narrative:

On the third of 4 legs following a stand-up overnight shift, cruising at 9000 ft, I received clearance to 11000 ft. I read back 'one-one' thousand and set 11000 ft in the alerter. At 10400 ft ZLA queried as to whether we were leveling at 10000 ft. I responded that I had been cleared to 11000 ft and was climbing to 11000 ft. Center then advised that the clearance had actually been to 10000 ft, and instructed me to return to 10000 ft. Virtually coincidental to the correction, center also advised of traffic at 12 O'clock (emb 120) and suggested a right turn 'about 10 degrees' heading change for separation. The emb 120 also turned to its respective right. The separation distance at point of passage was in excess of 1 NM and approximately 500 vertical ft.my recollection of center communications just prior to and during these events was the center controller had not communicated other xmissions to other aircraft clearly, as certain xmissions added some degree of confusion, requiring callbacks. After (subsequent leg) landing I was advised by area control land-line that the tapes revealed the controller had originally issued 10000 ft and that I had originally read back 10000 ft. However, I have not myself heard those recordings. Supplemental information from acn 292384: if we did deviate from our assigned altitude, then we need to listen to the radio more closely. Especially in very congested areas such as lax. There's so little room for mistakes. Secondly, commuter airlines scheduling issues such as stand-up overnight trips and ridiculous rest requirements as they are today should be overhauled to a less volatile system. A system where crew scheduling departments can no longer take advantage of gray areas. By this I am referring their interpretation of reduced rest as a tool, etc, in aviation accidents is bound to occur, but lack of rest is ctlable and should be no reason. Lastly, in our case, if the captain did read back one-one thousand, the controller should have corrected the captain's readback, all of which (standard procedure) would help us ascertain our goals towards safety, nonetheless, currently, the cards are stacked against us.

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Original NASA ASRS Text

Title: PLTDEV INCORRECT ALT.

Narrative: ON THE THIRD OF 4 LEGS FOLLOWING A STAND-UP OVERNIGHT SHIFT, CRUISING AT 9000 FT, I RECEIVED CLRNC TO 11000 FT. I READ BACK 'ONE-ONE' THOUSAND AND SET 11000 FT IN THE ALERTER. AT 10400 FT ZLA QUERIED AS TO WHETHER WE WERE LEVELING AT 10000 FT. I RESPONDED THAT I HAD BEEN CLRED TO 11000 FT AND WAS CLBING TO 11000 FT. CTR THEN ADVISED THAT THE CLRNC HAD ACTUALLY BEEN TO 10000 FT, AND INSTRUCTED ME TO RETURN TO 10000 FT. VIRTUALLY COINCIDENTAL TO THE CORRECTION, CTR ALSO ADVISED OF TFC AT 12 O'CLOCK (EMB 120) AND SUGGESTED A R TURN 'ABOUT 10 DEGS' HDG CHANGE FOR SEPARATION. THE EMB 120 ALSO TURNED TO ITS RESPECTIVE R. THE SEPARATION DISTANCE AT POINT OF PASSAGE WAS IN EXCESS OF 1 NM AND APPROX 500 VERT FT.MY RECOLLECTION OF CTR COMS JUST PRIOR TO AND DURING THESE EVENTS WAS THE CTR CTLR HAD NOT COMMUNICATED OTHER XMISSIONS TO OTHER ACFT CLRLY, AS CERTAIN XMISSIONS ADDED SOME DEG OF CONFUSION, REQUIRING CALLBACKS. AFTER (SUBSEQUENT LEG) LNDG I WAS ADVISED BY AREA CTL LAND-LINE THAT THE TAPES REVEALED THE CTLR HAD ORIGINALLY ISSUED 10000 FT AND THAT I HAD ORIGINALLY READ BACK 10000 FT. HOWEVER, I HAVE NOT MYSELF HEARD THOSE RECORDINGS. SUPPLEMENTAL INFO FROM ACN 292384: IF WE DID DEVIATE FROM OUR ASSIGNED ALT, THEN WE NEED TO LISTEN TO THE RADIO MORE CLOSELY. ESPECIALLY IN VERY CONGESTED AREAS SUCH AS LAX. THERE'S SO LITTLE ROOM FOR MISTAKES. SECONDLY, COMMUTER AIRLINES SCHEDULING ISSUES SUCH AS STAND-UP OVERNIGHT TRIPS AND RIDICULOUS REST REQUIREMENTS AS THEY ARE TODAY SHOULD BE OVERHAULED TO A LESS VOLATILE SYS. A SYS WHERE CREW SCHEDULING DEPTS CAN NO LONGER TAKE ADVANTAGE OF GRAY AREAS. BY THIS I AM REFERRING THEIR INTERP OF REDUCED REST AS A TOOL, ETC, IN AVIATION ACCIDENTS IS BOUND TO OCCUR, BUT LACK OF REST IS CTLABLE AND SHOULD BE NO REASON. LASTLY, IN OUR CASE, IF THE CAPT DID READ BACK ONE-ONE THOUSAND, THE CTLR SHOULD HAVE CORRECTED THE CAPT'S READBACK, ALL OF WHICH (STANDARD PROC) WOULD HELP US ASCERTAIN OUR GOALS TOWARDS SAFETY, NONETHELESS, CURRENTLY, THE CARDS ARE STACKED AGAINST US.

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.