The long and storied saga of the 787’s brake control monitoring system (BCMS) software has taken another strange turn with Boeing and supplier Crane Co. in a public spat over responsibility for the cost of the redesign of the software.
The redesign of the BCMS is the result of the relocation of a remote data concentrator (RDC) at the axles of the 787’s main landing gear, says Boeing. The relocation is necessary due to higher than expected temperatures in the brakes due to inadequate thermal protection of the RDCs, as well as the differences in thermal conductivity of composite material holding heat in the wheel well, supplier sources explain.
As a result, Boeing has recommended that airlines operating early production 787s use fans at the gate following high energy landings to dissipate the heat if a faster turnaround time is desired.
Another option available is leaving the gear down after takeoff to cool the brakes, however Boeing says they have not made that recommendation to airlines. Boeing was seen cooling ZA001’s brakes with fans during the taxi testing on July 7.
Remote data concentrators (RDCs) are used to flow digital and analog data from remote sensors into the 787’s Common Core System and replace traditional, dedicated signal wiring, saving weight and allowing increased operator flexibility.
Crane Co. says they are happy to make the change for future production aircraft (the first flight version has already been delivered) but Crane believes that Boeing should pay for the revision because the changes in the requirements are at the airplane level rather than the software level.
The strange episode may appear insignificant to the looming obstacle of actually getting the 787 to fly, but it situation illustrates a key challenge across the entire program that Boeing has had to regain control of its supply chain.
As the full extent of the chaos of the program became apparent in 2007, Boeing moved to reassert its control over the design process of the aircraft after many parts required modification because of changing requirements and inadequate designs that rippled across the integrated systems and structure of the aircraft.
Complicating matters further, many suppliers outsourced the design to outside engineering firms pushing control and oversight farther away from Boeing making changes that much more difficult. The situation ultimately underscores where supply chain management and ongoing engineering changes have intersected to disrupt the program.
In an effort to clean up the situation, Boeing has been perpetually working with suppliers to incorporate design changes back into the supply chain to reduce the workload in Everett. The result of these changes not being added before delivery to Everett has created what we know as traveled work.
Yet, as the delays have stretched longer than two years for the program, 787 suppliers like Crane Co. are getting restless with the growing cost of the redesigns and has only served to add further uncertainty to the financial position of the program at large.
Dow Jones quoted Crane Co. CEO
that we originally contemplated…and I can say that, universally among the
supply-chain community for this airplane, we are not alone and unfortunately [are] exceeding our original targets.”
Crane is only the most visible example of this issue, with sources across the 787 supply chain saying that negotiations about timing (and cost) of incorporation, though normal for a new aircraft program, have magnified the challenge of managing both the financial cost and sheer size of the global supply chain.
This post was originally published to the internet between 2007 and 2012. Links, images, and embedded media from that era may no longer function as intended.
This post originally appeared at Flightglobal.com from 2007 to 2012.