Federal Register #FAA-2026-7237

FAA Solicitation for Airworthiness Directive Compliance on Boeing 737-300, -400, and -500 Series Airplanes

The Federal Aviation Administration (FAA) is seeking compliance with a new airworthiness directive for Boeing 737-300, -400, and -500 series airplanes to address safety concerns related to frozen angle of airflow (AOA) sensor vanes. - Government Buyer: - Federal Aviation Administration (FAA), Transportation Department - OEMs and Vendors: - The Boeing Company (primary OEM) - Products/Services Requested: - Installation of new external case heaters (ECHs) on left and right AOA sensors - Repetitive functional tests and corrective actions for AOA sensors - Concurrent actions including: - Installation of junction boxes - Air data probe heat automation wire provisions - Replacement of insulation blankets with flame retardant material - Modification of circuit breaker panels - Modification or replacement of identification labels on AOA sensors - Repairs for cracks per Boeing instructions - Scope: - Estimated 133 U.S.-registered Boeing 737-300, -400, and -500 series airplanes affected - Unique/Notable Requirements: - Strict compliance with Boeing Alert Requirements Bulletin 73730A1081 RB, Revision 1 - Repairs must follow Boeing instructions if cracks are found - No specific part numbers provided; actions must be performed as outlined in Boeing documentation

Description

The FAA proposes a new airworthiness directive (AD) for certain Boeing Model 737-300, -400, and -500 series airplanes. This AD addresses reports of nuisance stick shaker activation caused by frozen angle of airflow (AOA) sensor vanes due to insufficient heat. The directive requires installing new external case heaters on the left and right AOA sensors, performing repetitive functional tests and corrective actions, and completing applicable concurrent actions. The goal is to prevent failure of the stall warning system and ensure continued safe flight and landing.

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