No doubt that Boeing is pushing the envelope with the 787. But that is something that the aerospace industry has done since day 1 of its existence.

The extensive use of composites (50% by weight) is probably the biggest risk. The technology in this area - materials, production, and inspection - has made significant advances since the early days when composites were used mostly for fairings and flight controls. But just like somebody decided many years ago to make the move from fabric and wood to aluminum, maybe it's time to move on to something better. Aluminum cracks, corrodes, and is prone to fatigue. Composites don't have those bad habits.

The decision to rely extensively on electrics instead of pneumatics should help increase dispatch reliabilability (look ma, no more air leaks or duct overheat warnings). With 2 250 kva generators on each engine and 2 225 kva generators on the APU, there should be plenty of juice to not only pressurize the airplane but to run all of the other goodies such as the HUDs, EFBs, electric brakes, and the stuff to keep the paying customers happy.

As for all the concerns that have been expressed on this thread, don't think for a minute that they haven't been raised by the airlines that have ordered or are considering the airplane. Most of these airlines (especially ones like ANA, Qantas, JAL, and Singapore) are very savvy and know what questions to ask and know what answers they want to hear. If Boeing had not been able to address issues such as repairability and temperature tolerance they wouldn't be ordering the airplane.

Boeing is betting its reputation (not to mention my retirement) on the 787. Rest assured that it is doing everything it can to make sure that the 787 will be a safe and reliable airplane.