Date: 201310
Local time of day: 1201-1800
Location: CYYZ.Airport, ON
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Other All
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Second reporter function: Captain; Pilot Flying
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Detector: Person Maintenance
When detected: Taxi
Result: Flight Crew Returned To Gate; General Flight Cancelled / Delayed
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: The aircraft we flew from ORD to YYZ had just come from heavy maintenance following a seat reconfiguration. We flew the leg by SOP and in accordance with the FARs and company policy. However; when we were taxiing out for our return leg; Load Planning said that we had to return to the gate as they had determined that the engineering tables in the computer didn't match the new configuration of the airplane. The Captain and I then determined that we had flown the previous leg most likely with improper weight and balance information since the engineering tables had not been updated at that time. After a 90 minute delay; the Captain; Maintenance Control; Dispatch; and Load Planning coordinated to have the proper engineering tables inserted into the computer for the new configuration. We then received the correct weights for our flight back.


Second narrative: THE AIRCRAFT HAD COME TO US FROM HEAVY MAINTENANCE AND SEATING CONFIGURATION CHANGE. ALL WENT AS PLANNED ON THE FIRST LEG; SO WE THOUGHT. IT WAS ON THE TAXI OUT ON THE RETURN FLIGHT THAT MY FIRST OFFICER AND I WERE TOLD THAT WE HAD TO RETURN TO THE GATE DUE TO THE FACT THAT LOAD PLANNING COULD NOT SEND US OUR FINAL WEIGHT AND BALANCE FIGURES. THEY DID NOT HAVE THE CURRENT SEATING CONFIGURATION AND ENGINEERING GRAPHS FOR OUR NEWLY CONFIGURED AIRCRAFT. WE HAD TO WAIT APPROXIMATELY 1 HOUR BEFORE WE RECEIVED THE OK FROM MAINTENANCE; A NEW DISPATCH RELEASE; AND AN ACCURATE FINAL WEIGHT MANIFEST AND WERE LEGAL FOR DISPATCH. DURING THIS PROCESS; I REALIZED THAT WE HAD DEPARTED IN THIS SAME AIRCRAFT. THERE WAS NO MENTION OF ANY ISSUES OR DISCREPANCIES ON THAT LEG BUT IT QUITE EVIDENT TO ME THAT IF WE DIDN'T HAVE THE PROPER ENGINEERING GRAPHS FOR THE SECOND LEG OUT AFTER THE AIRCRAFT'S RETURN TO SERVICE THEN WE DIDN'T HAVE THEM FOR THE FIRST LEG EITHER. MY FIRST OFFICER AND I WERE OF COURSE COMPLETELY UNAWARE OF ANY POSSIBLE ERROR; DISCREPANCY; ILLEGALITY UNTIL WE WERE BROUGHT INTO THE LOOP ON THE TAXI OUT. HAD I ANY CLUE THAT THE PROPER FINAL WEIGHTS WERE IN QUESTION; I WOULD HAVE NOT TAKEN OFF. TO THIS POINT; I'M STILL NOT SURE WHAT THE SOURCE OF THE ERROR WAS AND HOW DEEP DOES THIS 'RABBIT HOLE' GO. THE LOAD PLANNER SAID THAT WE WERE LEGAL BUT HAD THE WRONG NUMBERS. HOW COULD WE BE LEGAL THEN? HOW WRONG WERE THE NUMBERS? THE AIRCRAFT HANDLED FINE ON THE ENTIRE FLIGHT. ARICRAFT TRIMMING WAS IN A NORMAL RANGE THROUGH OUT THE FLIGHT SO I DON'T SUSPECT THAT WE WERE OUTSIDE OF THE NORMAL CG ENVELOPE BUT UNTIL THE NUMBERS ARE CRUNCHED; ONE CAN'T BE SURE. SINCE WE HAD NOT PASSED OUR POINT OF DISPATCH ON THE RETURN FLIGHT; THERE IS NO REPORT FOR THAT LEG.


Synopsis: A320 flight crew reports accepting an aircraft out of heavy maintenance after a seating configuration change and flying their first leg. Prior to the next leg it is discovered that the weight and balance data has not been change to reflect the new configuration.