EASA AD US-2023-05-04
Hydraulic Power - Ram Air Turbine Pump Barrel Assembly - Inspection
Summary
Airworthiness Directive 2023-05-04 is a final rule issued by the Federal Aviation Administration addressing all Boeing 787-8, 787-9, and 787-10 airplanes. It targets failures in the ram air turbine (RAT) pump barrel assembly caused by variations in the bronze metal used during manufacturing, which can lead to fatigue and cracking. The directive mandates inspections and replacements of affected RAT pump control modules and assemblies to ensure continued hydraulic power availability.
What Changed
This new airworthiness directive introduces mandatory inspections or records reviews to identify part numbers of the RAT pump control module and RAT assembly. It requires replacement of any parts with specified affected part numbers and prohibits installation of these parts on the affected Boeing 787 models. The directive corrects a typographical error in part numbers and clarifies applicability to all 787-8, 787-9, and 787-10 airplanes regardless of original configuration.
Why It Matters
This directive is critical for aviation professionals because failure of the RAT pump can result in loss of backup hydraulic power, which is essential for flight control safety. Operators and maintenance teams must ensure affected parts are identified and replaced promptly to prevent potential in-flight hydraulic failures. Compliance helps maintain airworthiness and reduces the risk of unsafe flight conditions related to hydraulic system failures.
What To Do
Operators of Boeing 787-8, 787-9, and 787-10 airplanes must inspect or review records to determine the part numbers of the RAT pump control module and RAT assembly. Any parts identified with the affected part numbers must be replaced with approved parts. Installation of the affected parts is prohibited. All actions must be completed by the effective date of May 12, 2023.
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