August 2012

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787 Update: What is Z18 and why does it matter?

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Across the entirety of Boeing's 787 global supply chain from Charleston to China, Nagoya to Naples and Winnipeg to Washington, executives, manufacturing planners and engineers are in the late stages in developing a document that will dictate the future of the planet's most ambitious industrial undertaking.

The document, known as Z18, the latest of 18 revisions to the 787 schedule, dictates all aspects of the fabrication, final assembly flow and customer delivery planning for each aircraft.

A preliminary version of Z18 has been examined by Boeing Commericial Airplanes CEO Scott Carson and is expected to be reviewed shortly by Boeing CEO Jim McNerney, senior program sources tell FlightBlogger.

Sources familiar with the schedule indicate that ZA001's first flight is likely to be slated for the late November/early December time frame, with first delivery to Japan's All Nippon Airways in the fourth quarter of 2010.

However, Boeing maintains that no decisions on the schedule have been made and the disclosure of the overall program timeline detailing first flight and aircraft certification will be announced by the end of September.

The development of Z18 is a closely held process that takes into account the short and long term production strategies, the ability of suppliers to ramp up and incorporate design changes, the capacity of final assembly operations, the requirements of airlines, as well as the financial considerations that impact the decision-making process.

Scott Fancher, 787 program vice president and general manager, was quoted in July as saying it was no secret that Boeing required a second final assembly line to support the production ramp up and meet the unprecedented demand for the aircraft.

Z18, as a result of this future requirement, could be the first program schedule that Boeing develops with provisions and planning for a second 787 assembly line in mind, no matter where it is located.

Fancher, who's responsible for the implementation of the schedule will require more art than science, his role likened to that of an orchestra conductor, ensuring that each of the partners moves in unison at the required tempo.

  • The latest on the Alenia/Section 46 wrinkles
  • What does Net Change 5 mean for the program?
Photo Credit Andrew Sieber

One important part of the orchestra in the minds of Boeing planners is the hold in fabrication at Alenia's Grottaglie, Italy facility, however Boeing believes it has devised a plan to ensure that the hold won't impact the planning for Z18.

Production does continue at Alenia, but Boeing confirmed that fabrication of new barrels stopped on June 23rd. The company stopped winding any new barrel sections until the stringer edge step size can be manufactured in such as way that does not wrinkle the skin of the Section 46 barrel.

Many were quick to assign blame that Boeing's outsourcing strategy was the culprit for the halt, yet Richard Aboulafia, vice president of analysis at the Teal Group explains that this explanation ignores a fundamental reality of the program.

"These are the best companies in the aerostructures world trying to grapple with building a completely new type of aircraft," says Aboulafia referring to the majority composite construction of the 787.

Yet the episode also underscores a key reality of the 787 program: The design of significant parts of the aircraft remain in flux enough to prompt an almost two-month halt in fabrication.

"The system is so fragile that it doesn't take much to knock it off course. If you're in control you can make it run properly, but there's steep learning curve here," says one industry expert.

At the time the work stop order was given, Alenia held 15 44/46 shipsets in Grottaglie. After deliveries in July and August to Global Aeronautica, that number dropped to 13, with Airplanes 17-29 currently in process in Italy.

Boeing has a devised a patch to repair the wrinkled areas Airplanes 5 through 29 to be applied in situ. The patch, Boeing says, will be applied in two locations on the Section 46 barrel, just above the frame of door number three on the port and starboard side of the aircraft. The patches, whose impact on the aerodynamics or weight of the aircraft is negligible, will be no wider than the width of the door which measures just under 50 inches wide.

Boeing says the patch "has already been designed and is being installed now at Global Aeronautica in South Carolina and will be installed at completed sections in Italy and Everett."

In order to avoid disruption in the flow of deliveries from Alenia to Global Aeronautica in Charleston, SC, Boeing will resequence work on the existing barrels sections currently in process in the factory. The Italian aerostructures manufacturer with shift resources previously allocated to winding barrels to preparing the existing shipsets for delivery.

For example, the installation of structural ribs and frames, a task previously done sequentially, will be done concurrently with the assistance of the added resources. With the structural preparation of the existing shipsets accelerating, Boeing says it intends to shift those same resources back to winding and installing structure in barrels for Airplane 30 and on once the redesign is complete, ultimately negating the halt in fabrication.

Boeing declined to specify how long barrel winding at Alenia could be halted for before the situation does impact planning for the Z18 or subsequent schedules. Though Boeing quickly adds that "there is no reason to think that it will affect schedule."

The delicate balance of shifting resources is risky, adds the industry expert, especially with the use of composite structural material from a supplier that has already demonstrated quality assurance issues in the past. Composite tape, once removed from its cold storage, will slowly cure even at room temperature if not properly handled.

"If you're going to do work on a couple of fuselages concurrently, you better have your [quality control] processes really in charge and really make sure you manage the time you have the materials on the floor and make sure there's no queuing problem in the oven, because you really can't wait."


While Z18 is being finalized, supply partners continue to deliver structural sections according to an interim Z17 schedule, which is likely to continue to dictate the final assembly schedule for up to Airplane 10, which could begin arriving as early as the end of this month.

Airplane 11 is expected to the be first 787 delivered to the Z18 schedule, says a senior program source. Airplanes 11, 12 or 13 will be first to see the cross-program implementation of what is being called Net Change 5 (NC5). NC5, among other things, includes a long-planned systematic change in the wiring definition for the 787. The decision about which of the the three aircraft will be the first to receive NC5 will be dictated by the constraints built into Z18.

Previously, suppliers like Spirit and Vought (now Boeing Charleston) had been able to deliver structural components with virtually 100% completion of assembly. However, once in Everett for final assembly, some of the internal stuffing had to be removed in order to perform design upgrades, for example the replacement of aircraft wiring.

NC5 will standardize the many aspects of the design, including structural, wiring and systems, across all the partners to reduce the amount of traveled work done in Everett and "bring some semblance of commonality between the sections arriving at Final Assembly," says one program source.

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