FAA Proposes New Airworthiness Directive for Boeing 787 Fleet
The Federal Aviation Administration (FAA) has mandated a critical safety upgrade for certain Boeing 787 Dreamliner models, requiring the replacement of transponder system components to prevent potential failures that could lead to a loss of aircraft tracking and increase the risk of mid-air collisions.
The Federal Aviation Administration (FAA) has issued a Notice of Proposed Rulemaking (NPRM) for a new airworthiness directive (AD) affecting certain Boeing Model 787-8, 787-9, and 787-10 airplanes. The proposed AD, detailed in Docket No. FAA–2025–0924, addresses a critical safety concern regarding the loss of transponder functionality when the aircraft encounters continuous wave (CW) interference.
The issue was prompted by multiple reports of transponders failing to meet the minimum operational performance standards (MOPS) for response in the presence of such interference. Specifically, the transponders did not correctly reply to at least 90 percent of interrogations, a condition that could lead to an unannounced loss of the Mode S transponder function. This failure could subsequently cause a loss of traffic alert and collision avoidance system (TCAS) advisory messages, increasing the risk of a mid-air collision.
To rectify this unsafe condition, the FAA is proposing a mandate to replace the left and right integrated surveillance system processor unit (ISSPU) hardware. The current hardware, with part numbers 822–2120–101 and 822–2120–102, would be replaced with the newer part number 822–2120–113. The proposed AD also requires an installation test to be performed and repeated until successful.
The FAA estimates that this directive will affect 150 airplanes on the U.S. registry. The estimated cost for the required actions is $53,001 per aircraft, which includes approximately four work-hours at a rate of $85 per hour and parts cost of $52,661. The total estimated cost for the U.S. fleet is projected to be $7,950,150.
The required actions and compliance times are detailed in the Boeing Alert Requirements Bulletin B787–81205–SB340065–00 RB, Issue 001, dated February 11, 2025.
The FAA is inviting public comment on this proposed AD. Comments must be received by July 28, 2025, and can be submitted through the Federal eRulemaking Portal at regulations.gov, by fax, mail, or hand delivery. All comments should reference Docket No. FAA–2025–0924 and Project Identifier AD–2025–00294–T.
The agency has determined that this action is necessary to ensure the continued safe operation of the affected Boeing 787 airplanes. The full text of the NPRM and related documents can be accessed on the AD docket at regulations.gov.
AUTOR
Desde 2017, haciendo periodismo aeronáutico. Award-Winning Journalist: Ganador de la edición 2023 de "Periodismo de Altura", otorgado por ALTA. Facts don't care about your feelings.
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