EASA SIB SAIB-2026-09
Hydraulic Power - Hydraulic Power Transfer Unit System
Summary
The FAA Special Airworthiness Information Bulletin SAIB: 2026-09 addresses errors found in Boeing Alert Requirements Bulletin 757-29A0071 RB, Original Issue, dated November 16, 2023, which affects The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes. This bulletin informs operators about issues related to the hydraulic power transfer unit (PTU) control valve and provides recommended actions to mitigate potential safety concerns. The document serves as an interim advisory prior to the anticipated supersedure of Airworthiness Directive 2024-25-09.
What Changed
This bulletin highlights identified errors in the Boeing Alert Requirements Bulletin 757-29A0071 RB that could introduce new hazards affecting the PTU operation. It brings attention to these issues and recommends reviewing Boeing Information Notices 757-29A0071 IN 01 and IN 02, as well as the Boeing Fleet Team Digest 757-FTD-29-20001, which clarify the errors and suggest corrective actions. The FAA plans to supersede AD 2024-25-09 once Boeing revises the service information to correct these errors.
Why It Matters
The PTU is a critical safety backup system for hydraulic power on Boeing 757 aircraft, especially during takeoff scenarios involving engine or pump failures. Errors in the service bulletin instructions could lead to improper maintenance actions, potentially compromising landing gear retraction and safe flight. Aviation professionals must be aware of these issues to ensure compliance, maintain aircraft safety, and avoid introducing new hazards during maintenance.
What To Do
Operators and maintenance personnel should promptly review Boeing Information Notices 757-29A0071 IN 01 and IN 02, and the Boeing Fleet Team Digest 757-FTD-29-20001, to understand the errors and recommended corrective measures. They should determine if deviations apply to their fleets and contact Boeing for possible alternative methods of compliance. Actions should be taken at the earliest opportunity to mitigate risks until the FAA issues the superseding AD.
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