BAD HARDWARE WEEK

Days before the fire, Boeing flew a Dreamliner to France for a look by Air France-KLM executives.

A French newspaper that said a worker left a metal tool in the electrical compartment.

Boeing Co. is modifying portions of the electrical system on its forthcoming Dreamliner, after an in-flight fire aboard a test plane two weeks ago again threw the timetable for the flagship program into doubt.

The move marks just the latest setback for the Dreamliner, which is running nearly three years behind schedule and is in danger of again missing a key milestone: its first delivery to a customer, which Boeing has projected for early next year.

The events also highlight the reliance of new planes on potentially fickle software and electrical systems. A post-fire power interruption caused a series of cascading power failures that affected many of the plane's systems, including autothrottle, computer flight-deck displays and electronic flight controls.But many of the 787's redundant electrical systems appeared to fail. Boeing long has maintained that the sophisticated electronics and software aboard the new Dreamliner were designed with many backups to avoid the kind of power-failure scenario encountered during the fire.

Bad Hardware: Is there pilot in the Airplane ! ? Though, a Federal Aviation Administration pilot was at the jet's controls when the fire broke out, and a Boeing test pilot was in the co-pilot's seat.