Summary
We propose to supersede Airworthiness Directive (AD) 2015-09- 07, which applies to all The Boeing Company Model 787 airplanes. AD 2015-09-07 requires a repetitive maintenance task for electrical power deactivation. Since we issued AD 2015-09-07, Boeing has developed new software for the generator control unit (GCU) that addresses the software counter overflow anomaly that prompted the issuance of AD 2015-09-07. This proposed AD would require installing the new GCU software. This proposed AD would also remove certain airplanes from the applicability. We are proposing this AD to address the unsafe condition on these products.