Federal Register #FAA20262726

FAA Proposes Airworthiness Directive for Boeing 737 Series Thrust Reverser Safety

The Federal Aviation Administration (FAA), under the Department of Transportation, is proposing new airworthiness directives (ADs) for Boeing 737-600, -700, -700C, -800, -900, and -900ER series airplanes to address thrust reverser safety concerns. - Government Buyer: - Federal Aviation Administration (FAA), Aircraft Certification Service - OEMs and Vendors: - The Boeing Company (primary OEM) - Products/Services Requested: - Inspection, testing, and operational checks of the upper locking hydraulic actuator for the thrust reverser system - On-condition actions including replacement of: - Upper locking hydraulic actuator manual unlock handle assembly torsion spring - Upper locking hydraulic actuator proximity sensor target - Upper locking hydraulic actuator - Revision of maintenance or inspection programs to incorporate specific certification maintenance requirements (CMR) per Boeing Alert Requirements Bulletin 737-78A1099 RB - Unique or Notable Requirements: - Compliance with Boeing Alert Requirements Bulletin 737-78A1099 RB - Incorporation of CMR items into maintenance programs - Addresses potential for incorrect actuator indications that could lead to uncommanded in-flight thrust reverser deployment and loss of control - Estimated to affect 1,805 U.S. Boeing 737 aircraft - No specific part numbers or quantities are provided in the directive - Place of Performance/Delivery: - FAA Airworthiness Products Section, Operational Safety Branch, Des Moines, WA - Boeing Commercial Airplanes Contractual & Data Services, Seal Beach, CA

Description

The FAA proposes a new airworthiness directive (AD) for all Boeing 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD addresses an unsafe condition where adjusting the upper locking hydraulic actuator proximity sensor targets per the aircraft maintenance manual could cause incorrect actuator indications, potentially leading to a thrust reverser indicating it is locked when it is not. The directive requires measurements, tests, operational checks, on-condition corrective actions, and revising the maintenance or inspection program to include certain certification maintenance requirements. The goal is to prevent possible uncommanded in-flight deployment of the thrust reverser, which could result in loss of control of the airplane.

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