EASA AD US-2024-19-06
Ice/Rain Protection System - Standby Power System Control Unit - Installation / Power Tests
Summary
The Federal Register document titled "Ice/Rain Protection System - Standby Power System Control Unit - Installation / Power Tests" is a final rule airworthiness directive (AD 2024-19-06) issued by the FAA. It applies to certain Boeing 737-8 and 737-9 airplanes and addresses a design issue in the standby power system control unit (SPCU) that poses a risk of single point failure. The directive mandates installation of four diodes, wiring bundle changes in the P5 panel, and subsequent installation and power tests to mitigate the unsafe condition.
What Changed
This new airworthiness directive introduces mandatory modifications to the SPCU on affected Boeing 737-8 and 737-9 aircraft. It requires installing four diodes and changing wire bundles in the P5 panel, along with performing installation and power tests. The AD also includes on-condition corrective actions if test failures occur.
Why It Matters
This AD is critical for aviation professionals because it addresses a potential single point of failure in the SPCU that could cause a complete loss of the battery bus and unannunciated loss of engine anti-ice systems. Compliance ensures continued safe operation by preventing loss of thrust due to icing-related damage. Operators, maintenance, and compliance teams must prioritize these modifications to maintain airworthiness and regulatory compliance.
What To Do
Affected operators must comply with the AD by November 26, 2024, installing the required diodes and wiring changes in the P5 panel and performing the specified power tests. If tests indicate issues, applicable corrective actions must be completed until successful. Operators should consult Boeing Alert Requirements Bulletin 737-30A083 RB, dated November 18, 2022, for detailed procedures and ensure documentation of compliance.