Electrical Power - New Software for the Generator Control Unit - Installation
- Published
- Effective
- Deadline
- Replaces
- 2015-09-07
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of affected Boeing 787 airplanes must install the new GCU software as specified in Boeing Service Bulletin B787-81205-SB240063-00, Issue 002, and concurrently install related software updates as required. Compliance with this AD is mandatory by November 20, 2018. Operators should review their fleet applicability, coordinate with Boeing for service information, and may use credit for prior approved service bulletin actions where applicable.
Summary
Airworthiness Directive 2018-20-15 is a final rule issued by the Federal Aviation Administration (FAA) that applies to all Boeing Model 787 airplanes. It mandates the installation of new software for the generator control unit (GCU) to prevent loss of all alternating current (AC) electrical power caused by the GCUs entering failsafe mode after 248 days of continuous power. This directive also removes certain airplanes from its applicability.
What changed
This AD supersedes Airworthiness Directive 2015-09-07 by replacing the repetitive maintenance task for electrical power deactivation with a requirement to install new GCU software. It also updates the applicability by excluding certain airplanes and allows operators to install later-approved software versions without needing alternative methods of compliance (AMOCs). Additionally, it provides credit for certain prior service bulletin actions.
Why it matters
This directive addresses a critical unsafe condition where continuous powering of Boeing 787 airplanes for extended periods can cause all AC electrical power to be lost, potentially leading to loss of airplane control. Compliance ensures enhanced electrical system reliability and safety, reducing operational risks for airlines and maintenance organizations. It also clarifies warranty coverage and software update procedures, aiding compliance and maintenance planning.
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