Narrative:

This report is being prepared after listening to a tape recording between our flight and cle center. Apparently what happened was: while climbing through 23000' up to our assigned altitude of 29000', I advised my copilot that I would be off center frequency to make a passenger announcement. The flight engineer handed me an ACARS message from dispatch alerting us to turbulence and wind shear for lga and all the ny area airports. He then proceeded to reload the printer. About this time the copilot accepted a center frequency change and reported leaving FL240 climbing to FL290. Cle center advised we had 'crossing 310 traffic higher when clear.' next center said, 'traffic 11 O'clock, 20 mi, wbound, 310.' copilot acknowledged, '310 large transport.' apparently that is when he set 31000' in our altitude alert. Next, center called air carrier B stating his traffic (us), '1 O'clock, 20 mi, climbing southeast 26 climbing 29.' reply was, 'air carrier B.' then center read a long SIGMET about severe turbulence from ground up to 7000' and wind shear over a large area of the northeast us climbing through about 29800' we watched the traffic pass overhead at FL310. Next, copilot reported, 'leveling 310 requesting higher.' center immediately clrd us to FL330. A little later center said we had only been clrd to FL290, and then clrd us on to FL370. Next call was for bos center on 133.95. Prior to listening to the tape, at no time during the entire flight did I believe we had deviated from an assigned altitude or pass less than 2000' vertical from the the other aircraft. No action was taken by us until arriving at the layover hotel. There, a message from dispatch was waiting for me, to call cle center about a possible altitude violation. Some possible areas to consider towards improving safety: 1) simplify routing and number of maps needed between yyz and lga. 2)proper radio terminology by copilot. 3) extra alert in monitoring of radio when 1 member is not able to listen to frequency. 4) a better way of alerting an aircraft when it enters the buffer zone around another aircraft. We were never alerted about our going through our altitude until we had actually passed the traffic. Supplemental information from acn 80431: in the climb from FL270 to FL310 I heard the cle center then clear us to continue climb to FL310. During entire time I had the traffic in sight. Passing FL298 I saw traffic pass off to our right side at approximately 1/2 mi. At that time I called cle center and reported out of FL300 for FL310 and he informed me that we had only been clrd to FL290 because of the traffic that passed us to the right. I actually thought we had been clrd to FL310 and set 310 in the altitude alert. Everyone on the flight deck also thought we were clrd to FL310. Maybe a long crew duty day (13 hours) and overanticipation to get to crs altitude caused me to hear an altitude given in an informative manner and I took it as a clearance to climb. Supplemental information from acn 80478: after level-off at FL290 center called crossing traffic at FL310. The transmission led us to believe we were clrd to FL310.

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Original NASA ASRS Text

Title: ACR LGT OVERSHOT ALT ON CLIMB RESULTING LESS THAN STANDARD SEPARATION.

Narrative: THIS RPT IS BEING PREPARED AFTER LISTENING TO A TAPE RECORDING BTWN OUR FLT AND CLE CENTER. APPARENTLY WHAT HAPPENED WAS: WHILE CLBING THROUGH 23000' UP TO OUR ASSIGNED ALT OF 29000', I ADVISED MY COPLT THAT I WOULD BE OFF CENTER FREQ TO MAKE A PAX ANNOUNCEMENT. THE FE HANDED ME AN ACARS MESSAGE FROM DISPATCH ALERTING US TO TURBULENCE AND WIND SHEAR FOR LGA AND ALL THE NY AREA ARPTS. HE THEN PROCEEDED TO RELOAD THE PRINTER. ABOUT THIS TIME THE COPLT ACCEPTED A CENTER FREQ CHANGE AND RPTED LEAVING FL240 CLBING TO FL290. CLE CENTER ADVISED WE HAD 'XING 310 TFC HIGHER WHEN CLR.' NEXT CENTER SAID, 'TFC 11 O'CLOCK, 20 MI, WBOUND, 310.' COPLT ACKNOWLEDGED, '310 LGT.' APPARENTLY THAT IS WHEN HE SET 31000' IN OUR ALT ALERT. NEXT, CENTER CALLED ACR B STATING HIS TFC (US), '1 O'CLOCK, 20 MI, CLBING SE 26 CLBING 29.' REPLY WAS, 'ACR B.' THEN CENTER READ A LONG SIGMET ABOUT SEVERE TURBULENCE FROM GND UP TO 7000' AND WIND SHEAR OVER A LARGE AREA OF THE NE U.S. CLBING THROUGH ABOUT 29800' WE WATCHED THE TFC PASS OVERHEAD AT FL310. NEXT, COPLT RPTED, 'LEVELING 310 REQUESTING HIGHER.' CENTER IMMEDIATELY CLRD US TO FL330. A LITTLE LATER CENTER SAID WE HAD ONLY BEEN CLRD TO FL290, AND THEN CLRD US ON TO FL370. NEXT CALL WAS FOR BOS CENTER ON 133.95. PRIOR TO LISTENING TO THE TAPE, AT NO TIME DURING THE ENTIRE FLT DID I BELIEVE WE HAD DEVIATED FROM AN ASSIGNED ALT OR PASS LESS THAN 2000' VERT FROM THE THE OTHER ACFT. NO ACTION WAS TAKEN BY US UNTIL ARRIVING AT THE LAYOVER HOTEL. THERE, A MESSAGE FROM DISPATCH WAS WAITING FOR ME, TO CALL CLE CENTER ABOUT A POSSIBLE ALT VIOLATION. SOME POSSIBLE AREAS TO CONSIDER TOWARDS IMPROVING SAFETY: 1) SIMPLIFY ROUTING AND NUMBER OF MAPS NEEDED BTWN YYZ AND LGA. 2)PROPER RADIO TERMINOLOGY BY COPLT. 3) EXTRA ALERT IN MONITORING OF RADIO WHEN 1 MEMBER IS NOT ABLE TO LISTEN TO FREQ. 4) A BETTER WAY OF ALERTING AN ACFT WHEN IT ENTERS THE BUFFER ZONE AROUND ANOTHER ACFT. WE WERE NEVER ALERTED ABOUT OUR GOING THROUGH OUR ALT UNTIL WE HAD ACTUALLY PASSED THE TFC. SUPPLEMENTAL INFORMATION FROM ACN 80431: IN THE CLB FROM FL270 TO FL310 I HEARD THE CLE CENTER THEN CLR US TO CONTINUE CLB TO FL310. DURING ENTIRE TIME I HAD THE TFC IN SIGHT. PASSING FL298 I SAW TFC PASS OFF TO OUR RIGHT SIDE AT APPROX 1/2 MI. AT THAT TIME I CALLED CLE CENTER AND RPTED OUT OF FL300 FOR FL310 AND HE INFORMED ME THAT WE HAD ONLY BEEN CLRD TO FL290 BECAUSE OF THE TFC THAT PASSED US TO THE RIGHT. I ACTUALLY THOUGHT WE HAD BEEN CLRD TO FL310 AND SET 310 IN THE ALT ALERT. EVERYONE ON THE FLT DECK ALSO THOUGHT WE WERE CLRD TO FL310. MAYBE A LONG CREW DUTY DAY (13 HRS) AND OVERANTICIPATION TO GET TO CRS ALT CAUSED ME TO HEAR AN ALT GIVEN IN AN INFORMATIVE MANNER AND I TOOK IT AS A CLRNC TO CLB. SUPPLEMENTAL INFORMATION FROM ACN 80478: AFTER LEVEL-OFF AT FL290 CENTER CALLED XING TFC AT FL310. THE XMISSION LED US TO BELIEVE WE WERE CLRD TO FL310.

Data retrieved from NASA's ASRS site as of August 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.