Boeing's two-week hold on 787 shipments has overshadowed an even longer period of non-movement in the final assembly line, as the company works to address lingering horizontal stabiliser issues.

Driving the latest hold -- the third this year -- is a shifted delivery schedule of the Alenia Aeronautica-built 787 horizontal stabiliser and the need to deliver a shipset free of workmanship issues, first disclosed in June, that would need time consuming rework at Boeing's Everett, Washington, final assembly facility, says Boeing.

Yet, as Boeing disclosed the two two-week hold on shipset deliveries, structural sections had already been accumulating in the back of the factory as the assembly line has not advanced since early October for Airplane 28. The line is not set to pulse again until early November and could stretch to the middle of the month, according to those working on the program.

As recently as August, when Boeing slid first delivery to All Nippon Airways to mid-first quarter 2011, Boeing Commercial Airplanes chief executive Jim Albaugh expressed confidence in the recovery plan, saying "horizontal stabiliser 27 and on we're not too worried about, we've got that one pretty well overwhelmed."

Though horizontal stabilisers 28 and 29 will still require inspection and potentially significant rework. Boeing now expects the first "clean" stabiliser free of workmanship issues to be delivered from Italy starting with Airplane 30.

The US airframer has found itself in a complicated dance of horizontal stabilisers inside the factory as they are reworked. Boeing, meanwhile, is making provisions to support the rework required to fix the Alenia workmanship issues.

"Detailed inspections [of the horizontal stabilisers] are continuing at the same time we are building," says Boeing.

The four-position 787 line is stocked with Airplanes 25 (Air India), 26 (Air India), 27 (JAL) and 28 (Air India) at assembly positions, while a near-complete complement of parts for Airplane 29 waits in pieces at the rear of the factory along with the wings for Airplane 30.

Notably missing from both planes are the horizontal stabilisers for Airplanes 29 and 30, two shipsets behind.

Another programme source expects the horizontal stabiliser for Airplane 29 to arrive in the coming days, with number 30 to arrive in Everett once the delivery hold is lifted early next month.

The remaining parts for Airplane 30, the forward and aft fuselage, are being stored in a Dreamlifter away from the elements.

Airplanes 25, 27 and 28 all have horizontal stabilisers, though each is heavily stripped down while being reworked. Airplane 26 remains without a horizontal stabiliser as the line-move trumped the installation, which occurred while it was being reworked.

After Airplane 26 advanced to position two, Airplane 27 was fitted with the horizontal stabiliser intended for Airplane 26 after preliminary rework was complete, while the airplane was in position one inside the factory.

The stabiliser originally meant for Airplane 27 is now installed on Airplane 28.

The horizontal stabiliser for Airplane 29, when it arrives from Italy, is likely to be installed on Airplane 26 before it leaves the factory prior to loading of Airplane 30 into final body join.

Boeing's first delivery hold, announced in late April, stretched into early June, with a second lasting a total of 28 days split between 10 manufacturing days preceding delivery of Airplane 26, and another covering 18 manufacturing days following the arrival of the wings of Airplane 28.

Horizontal stabiliser 28 remains in the horizontal stabiliser integration (HSI) tool on the factory floor, and will likely be loaded on Airplane 29 once the line advances forward. Boeing will re-sync the horizontal stabilisers beginning again with Airplane 30 when deliveries resume again.

The last time Boeing's line advanced was on 3 October, and the shifting of the 787 line forward was initially scheduled for 13 October, followed by another move on 25 October, though neither took place opting to hold the line in place on both occasions. The company says the line won't move again until November 4 at the earliest, despite a complete shipset for Airplane 29, which now includes Airplane 28's stabiliser, in the factory.

Though one source in program manufacturing indicates that another line hold could be instituted, pushing the next forward move, and the start of assembly of the 29th 787, to mid-November.

As it anticipates the need to conduct rework on the existing production horizontal stabilisers out of the normal assembly sequence, Boeing has added a new laydown position in the rear of the factory to rework the stabilisers before moving to the HSI tool for integration.

In that August interview, Albaugh added the company would be able to perform any required rework without removing the horizontal stabiliser, which remains true. However, with repairs involving invasive rework, crews may have to remove the tail cone and vertical tail plane of the aircraft to gain access the the stabiliser.

Boeing has developed a new tool to rework the horizontal stabilisers that accommodates a holding slot for the KAL-ASD-built Section 48 aft tail cone and vertical stabiliser and a work area to provide unfettered access to the horizontal stabiliser.

For the production-airframe horizontal stabilisers, most of which have been installed, programme sources say Boeing is now inspecting the shims, some found to have gaps as large as .25 to .5cm, on 600 areas of the fixed leading and trailing edges of the horizontal stabiliser.

Initially the inspection of the horizontal stabilisers on the six flight test aircraft encompassed a small area of two shims and 24 potentially over-torqued fasteners, though Boeing concedes that scope of the initial problem has grown since first discovery in late June necessitating additional inspections and modifications of the flight test aircraft.

Boeing 787 vice president and general manager Scott Fancher said in June that the flight test aircraft rework would take between one and eight days depending on the amount of work required, however for the horizontal stabilisers on production airframes are expected to take significantly longer, say programme sources.

Source: Air Transport Intelligence news