Narrative:

Operating an aircraft as flight XXX from norfolk, va, to atl, GA. While climbing through approximately 22000' en route to 25000' assigned, I began to make preparations to make a welcome aboard passenger announcement. During the passenger announcement, ZDC called and assigned FL270 as our next altitude. Out of the corner of my eye, I noticed the captain reach up and change the altitude command window on the flight guidance computer panel. I also heard him acknowledge the climb to FL270 on the cockpit speakers (I had my headset on and had deselected the VHF-1 receiver). After completing the passenger announcement, I pulled out the high chart to get a VOR frequency for another NAVAID down the flight planned route. After getting the frequency, I then got back in the loop as far as monitoring the aircraft and navigation. ZDC called back and told us of traffic at 12 O'clock for some distance at FL280 and stated 'higher when clear.' my first indication of a potential problem was when the TCAS alerted 'traffic, traffic.' I looked at the display and noted the opposing traffic was indicating only about 600' above us and on a converging heading. I asked center the assigned altitude of the opposing traffic and was told FL280. The captain then disconnected the autoplt and descended back to FL270. At this point, we finally noticed the altitude in the command window to be 28000'. My mistake was not backing up the captain on the altitude set in the window. When I heard him read back FL270 and saw his hand move to change the altitude in the command window, I 'ass U me D' he had set the correct altitude. Even though involved in some other cockpit crew duty, once back in the loop it is imperative to check all parameters of altitude, airspeed and heading that have been assigned by ATC.

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Original NASA ASRS Text

Title: TCAS ALERT CAUSED FLT CREW TO BECOME AWARE OF ALT DEVIATION.

Narrative: OPERATING AN ACFT AS FLT XXX FROM NORFOLK, VA, TO ATL, GA. WHILE CLBING THROUGH APPROX 22000' ENRTE TO 25000' ASSIGNED, I BEGAN TO MAKE PREPARATIONS TO MAKE A WELCOME ABOARD PAX ANNOUNCEMENT. DURING THE PAX ANNOUNCEMENT, ZDC CALLED AND ASSIGNED FL270 AS OUR NEXT ALT. OUT OF THE CORNER OF MY EYE, I NOTICED THE CAPT REACH UP AND CHANGE THE ALT COMMAND WINDOW ON THE FLT GUIDANCE COMPUTER PANEL. I ALSO HEARD HIM ACKNOWLEDGE THE CLB TO FL270 ON THE COCKPIT SPEAKERS (I HAD MY HEADSET ON AND HAD DESELECTED THE VHF-1 RECEIVER). AFTER COMPLETING THE PAX ANNOUNCEMENT, I PULLED OUT THE HIGH CHART TO GET A VOR FREQ FOR ANOTHER NAVAID DOWN THE FLT PLANNED RTE. AFTER GETTING THE FREQ, I THEN GOT BACK IN THE LOOP AS FAR AS MONITORING THE ACFT AND NAV. ZDC CALLED BACK AND TOLD US OF TFC AT 12 O'CLOCK FOR SOME DISTANCE AT FL280 AND STATED 'HIGHER WHEN CLR.' MY FIRST INDICATION OF A POTENTIAL PROB WAS WHEN THE TCAS ALERTED 'TFC, TFC.' I LOOKED AT THE DISPLAY AND NOTED THE OPPOSING TFC WAS INDICATING ONLY ABOUT 600' ABOVE US AND ON A CONVERGING HDG. I ASKED CENTER THE ASSIGNED ALT OF THE OPPOSING TFC AND WAS TOLD FL280. THE CAPT THEN DISCONNECTED THE AUTOPLT AND DSNDED BACK TO FL270. AT THIS POINT, WE FINALLY NOTICED THE ALT IN THE COMMAND WINDOW TO BE 28000'. MY MISTAKE WAS NOT BACKING UP THE CAPT ON THE ALT SET IN THE WINDOW. WHEN I HEARD HIM READ BACK FL270 AND SAW HIS HAND MOVE TO CHANGE THE ALT IN THE COMMAND WINDOW, I 'ASS U ME D' HE HAD SET THE CORRECT ALT. EVEN THOUGH INVOLVED IN SOME OTHER COCKPIT CREW DUTY, ONCE BACK IN THE LOOP IT IS IMPERATIVE TO CHK ALL PARAMETERS OF ALT, AIRSPD AND HDG THAT HAVE BEEN ASSIGNED BY ATC.

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.