Date: 201201
Local time of day: 0601-1200
Location: ORD.Airport, IL
Light: Daylight
Aircraft: B777-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi; Takeoff / Launch
Airspace: Class B ORD
ATC / advisory: Ramp ORD
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Situational Awareness; Training / Qualification; Workload; Confusion; Communication Breakdown
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Dispatch; Person Ground Personnel
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Company Policy; Procedure; Chart Or Publication
Primary problem: Ambiguous

Narrative: Flight planned for max weight takeoff of 545;000#. We were delayed departing due to baggage loading. During taxi final ZFW of 396;965# given. With that ZFW weight at takeoff was 544;900# (within limits). After takeoff we were advised of an error in ZFW. New ZFW 399;532#. We were subsequently advised again of another new final ZFW of 399;532#. Based on those ZFWs we had taxied and taken off over our max allowable structural weight. We updated the ZFW in the FMC in flight. Maintenance inspection was to be accomplished after landing.  As an added note to all of this; our new performance takeoff data using SCAP data unbalances the field and reduces required takeoff thrust to a minimum. What; if any; 'pad' this offers is unknown to the crews. The actual runway or performance limits (and available 'pads') are unknown to the crews. Crews were previously more involved; and able to make 'judgment' decisions on flap / runway / takeoff power setting decisions. Crews are now more out of the loop than ever. On this day we were legal for an intersection takeoff and reduced thrust takeoff using full length at the lowest flap setting. Due to winter weather conditions we elected to takeoff full length; max thrust; flaps 15. What kind of runway limit 'pad' did that give us? Don't know under the new process other than it had to be better. How did that affect our performance limit? Don't know under the new process other than it had to be less than flaps 5. With current combination of temperature; airport; and runway we knew performance limit wouldn't be an issue (from experience). All we knew for certain from the supplied runway data was that MTOG (Maximum takeoff weight) remained at 545;000# (structural limit). The PIC is the one on site to make judgment calls. The new procedures do not give the PIC the resources or information to fully use this judgment. This can lead to perhaps less than optimum decisions. The further we take the PIC out of the process and not supply sufficient information; or resources; the worse the situation will become over time and another critical safety component (the PIC) is increasingly removed from the process.




Synopsis: A B777 was notified after takeoff that its taxi weight was over its maximum zero fuel weight (MZFW). The new Company performance data calculations leave the flight crew out of the loop about takeoff runway selection; power settings and other information.