More trouble for Boeing's Dreamliner as bug 'could cause loss of control'

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More trouble for Boeing's Dreamliner as bug 'could cause loss of control'

Boeing's troubled 787 aircraft is at risk of total electrical shutdown, US safety watchdog warns

PUBLISHED : Sunday, 03 May, 2015, 12:31am
UPDATED : Sunday, 03 May, 2015, 12:31am

The Guardian

The US air safety authority has issued a warning and maintenance order over a software bug that causes a complete electric shutdown of Boeing's 787 Dreamliner and potentially "loss of control" of the aircraft.

In the latest of a line of problems plaguing the Dreamliner, which saw the company's fleet grounded over battery issues and concerns about possible hacking vulnerabilities, the new software bug was found in the plane's generator-control units.

The plane's electrical generators fall into a fail-safe mode if kept continuously powered on for 248 days. The 787 has four such main generator-control units that, if powered on at the same time, could fail and cause an electrical shutdown.

"We are issuing this AD [airworthiness directive] to prevent loss of all AC electrical power, which could result in loss of control of the aeroplane," said the Federal Aviation Administration directive. "If the four main generator control units [associated with the engine-mounted generators] were powered up at the same time, after 248 days of continuous power, all four GCUs will go into fail-safe mode at the same time, resulting in a loss of all AC electrical power regardless of flight phase."

Should the electrical shutdown happen at a critical phase in flight such as take-off or landing, or while manoeuvring in the air, the loss of control could be catastrophic.

The FAA considered the situation critical and issued the new rule without allowing time for comment. Boeing is working on a software upgrade for the control units that should rectify the bug.

"The airworthiness directive action addresses a condition that only occurred in the lab. Simulated testing determined that this condition is possible in cases where an aeroplane's power is left on for more than eight continuous months. No airplane in the fleet experienced that condition," a Boeing spokesman said.