The FAA has proposed a new airworthiness directive (AD) for certain Boeing 737-8, 737-9 and 737-8200 airplanes, marketed as the 737 MAX 8, MAX 9 and MAX 200, after receiving a report that bearings in the elevator buss assembly, a component that helps move the aircraft’s control columns as part of the elevator control system, may have been installed incorrectly during production, in some cases without the application of sealant. The proposal was published in the Federal Register on 21 September as a Notice of Proposed Rulemaking, under Docket No. FAA-2026-8811.

WHAT COULD GO WRONG

Incorrect installation of the bearings could lead to cracking in the elevator buss assembly bearings and their housings, which the FAA says could in turn cause premature failure of the assembly’s crank arms. Left unaddressed, the agency warns, this could affect elevator pitch control and the continued safe flight and landing of the aircraft. The FAA states it is proposing the AD “to address the unsafe condition on these products,” having determined that the condition is likely to exist or develop on other aircraft of the same type design.

WHAT THE DIRECTIVE WOULD REQUIRE

The proposed AD, based on Boeing’s Alert Requirements Bulletin 737-27A1331 RB of 17 December 2025, would require detailed inspections of the elevator buss assembly bearings and their housings for cracking and for evidence that sealant was applied, along with any resulting on-condition actions. Those on-condition actions include a push-out load test of bearings carrying three specific part numbers and, depending on the results, replacement of an affected bearing, repair of the elevator buss assembly, or replacement of the assembly entirely.

COST AND HOW TO COMMENT

The FAA estimates the AD would affect 95 airplanes on the US registry, with the inspection alone costed at 1,955 dollars per aircraft, or 185,725 dollars across the fleet; the agency says it has no reliable way to estimate how many aircraft will need the further, more costly on-condition repairs, which range from an 85 dollar push-out load test to a full elevator buss assembly replacement estimated at 98,496 dollars per aircraft. Boeing has told the FAA that some or all of these costs may be covered under warranty. The FAA must receive public comments on the proposal by 5 November 2026, referencing Docket No. FAA-2026-8811 and Project Identifier AD-2025-01891-T, submitted through the regulations.gov portal, by fax, by mail, or by hand delivery to the Department of Transportation’s Docket Operations in Washington, D.C.