The FAA Requires a Software Change After a Report That the Crew Alerting System Did Not Indicate a Failed Slat Extension During Landing

The Federal Aviation Administration published airworthiness directive 2026-11-03 in the Federal Register on June 4, 2026, as a final rule. It applies to certain airplanes of one model, which the FAA says have been approved by the civil aviation authority of another country and are approved for operation in the United States, and it took effect on July 9, 2026. The FAA estimates that it "affects 25 airplanes of U.S. registry." Parts of the directive follow, not the whole.

A Failure the Crew Was Not Shown

The directive "was prompted by a report of a failed extension of the inboard slats during the landing phase, which the crew alerting system (CAS) did not indicate to the flightcrew." The FAA issued it, in its own words, "to address the failed extension of inboard slats during landing phase without flightcrew indication."

Without flightcrew indication.

The unsafe condition, the directive says, "if not addressed, could lead to reduced lift margin during approach and landing and result in reduced control of the airplane."

The slats were one failure. The warning that did not appear was the second, and it is the one that left the crew without the information.

Software and the Flight Manual

The directive "requires modifying the maintenance and avionics interface computer (MAIC) software and revising the existing airplane flight manual (AFM) to provide improved procedures for addressing slat failures." The FAA refers to a directive of the European Union Aviation Safety Agency, EASA AD 2025-0092, dated April 23, 2025, as the mandatory continuing airworthiness information, or MCAI. The requirements paragraph of the FAA's directive reads, "Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, EASA AD 2025-0092."

According to the FAA, the MCAI states that the manufacturer has developed a modification "that introduces changes to the MAIC software to restore crew awareness about the inboard slat configuration in case of slat failures." The material the directive incorporates specifies upgrading the MAIC software, including a change to the standard of the digital flight control system, to ensure that the crew alerting message "FCS: SLAT INB EXTEND FAIL" is properly displayed.

An Interim Action, Adopted as Proposed

"The FAA considers that this AD is an interim action." If EASA later determines that it is necessary to expand the applicability to airplanes that have not embodied a particular modification, the FAA says, it "might consider further rulemaking." The FAA received no comments on its proposal, published on March 10, 2026, or on its determination of the cost, and adopted the directive as proposed except for minor editorial changes.