Narrative:

We departed sna via the FMS SID and received vectors to the trm VOR with a clearance to climb to 13000 ft. We were soon cleared to 14000 ft and prior to reaching 14000 ft, assigned 15000 ft. As the PNF, I set in the altitude window. Included with the clearance to climb to 15000 ft was a TA for an aircraft at 16000 ft and 2 O'clock position. I did not call out '14000 ft for 15000 ft' as I read back 'one-five thousand' to ATC and looked for traffic. While looking for the traffic, the captain called out '15000 ft for 16000 ft.' I looked back at the altitude window and saw 16000 ft set. The captain had reset the altitude to 16000 ft thinking that was the altitude we were cleared to, mistaking the other traffic altitude for our assigned altitude. There was a lag in my actions as I was confused as to 'who' had set 16000 ft in the window or if in fact this altitude was correct. We were soon informed that we should have been at 15000 ft, not 16000 ft. No conflict occurred. The captain should not have reset the altitude without checking with me or more properly, letting the PNF set altitudes, as is our policy. However, my not calling out '14000 ft for 15000 ft' due to the ATC readback and high rate of climb could have reinforced to the captain that we were indeed cleared to 16000 ft. Supplemental information from acn 481356: the clearance that I mistakenly thought was for us, was actually for our traffic to maintain 16000 ft. There was a nearly constant stream of clrncs to many aircraft in the area and I simply did not question this one carefully enough before starting the climb. The controller leveled the other aircraft at 17000 ft and no near miss occurred.

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Original NASA ASRS Text

Title: A B757 FLC CLBS ABOVE THEIR ASSIGNED ALT WHEN THE PF, THE PIC, SETS HIS OWN ALT ALERT FOR THE OTHER RPTED TFC'S ALT 25 MI SE OF PSP, CA.

Narrative: WE DEPARTED SNA VIA THE FMS SID AND RECEIVED VECTORS TO THE TRM VOR WITH A CLRNC TO CLB TO 13000 FT. WE WERE SOON CLRED TO 14000 FT AND PRIOR TO REACHING 14000 FT, ASSIGNED 15000 FT. AS THE PNF, I SET IN THE ALT WINDOW. INCLUDED WITH THE CLRNC TO CLB TO 15000 FT WAS A TA FOR AN ACFT AT 16000 FT AND 2 O'CLOCK POS. I DID NOT CALL OUT '14000 FT FOR 15000 FT' AS I READ BACK 'ONE-FIVE THOUSAND' TO ATC AND LOOKED FOR TFC. WHILE LOOKING FOR THE TFC, THE CAPT CALLED OUT '15000 FT FOR 16000 FT.' I LOOKED BACK AT THE ALT WINDOW AND SAW 16000 FT SET. THE CAPT HAD RESET THE ALT TO 16000 FT THINKING THAT WAS THE ALT WE WERE CLRED TO, MISTAKING THE OTHER TFC ALT FOR OUR ASSIGNED ALT. THERE WAS A LAG IN MY ACTIONS AS I WAS CONFUSED AS TO 'WHO' HAD SET 16000 FT IN THE WINDOW OR IF IN FACT THIS ALT WAS CORRECT. WE WERE SOON INFORMED THAT WE SHOULD HAVE BEEN AT 15000 FT, NOT 16000 FT. NO CONFLICT OCCURRED. THE CAPT SHOULD NOT HAVE RESET THE ALT WITHOUT CHKING WITH ME OR MORE PROPERLY, LETTING THE PNF SET ALTS, AS IS OUR POLICY. HOWEVER, MY NOT CALLING OUT '14000 FT FOR 15000 FT' DUE TO THE ATC READBACK AND HIGH RATE OF CLB COULD HAVE REINFORCED TO THE CAPT THAT WE WERE INDEED CLRED TO 16000 FT. SUPPLEMENTAL INFO FROM ACN 481356: THE CLRNC THAT I MISTAKENLY THOUGHT WAS FOR US, WAS ACTUALLY FOR OUR TFC TO MAINTAIN 16000 FT. THERE WAS A NEARLY CONSTANT STREAM OF CLRNCS TO MANY ACFT IN THE AREA AND I SIMPLY DID NOT QUESTION THIS ONE CAREFULLY ENOUGH BEFORE STARTING THE CLB. THE CTLR LEVELED THE OTHER ACFT AT 17000 FT AND NO NEAR MISS OCCURRED.

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.