Airworthiness directive
FAA orders stabilizer checks on nearly 2,000 Boeing 737NGs over flutter risk
The FAA now requires freeplay checks of the horizontal stabilizer on nearly 2,000 US registered 737NGs, after pitch oscillation reports the agency says could progress to flutter.
The FAA adopted Airworthiness Directive 2026-20-14 on 19 October 2026, requiring freeplay measurements of the horizontal stabilizer's pivot hinges and jackscrew on Boeing 737-600, -700, -700C, -800, -900 and -900ER aircraft, the agency said in the Federal Register. The directive follows reports from multiple operators of pitch oscillation events, which the FAA said could progress to a flutter event and a loss of control if left unaddressed. Simple Flying and AeroTime both reported the final rule, citing the same Federal Register document.
The FAA put the affected fleet at 1,987 US registered aircraft and said the 737 MAX is not included, since its stabilizer assembly differs from the NG's. The rule takes effect 23 November 2026.
In plain terms
Freeplay is the small amount a part can move before it engages the next part in a mechanism. Too much of it in a flight control surface's mounting can let that surface start oscillating on its own in flight, a condition called flutter, which can damage or detach the structure if it is not caught early.
The directive requires measuring freeplay at both pivot hinges and the jackscrew under Boeing Alert Requirements Bulletin 737-55A1104 RB, with repair or replacement to follow depending on the reading. According to Simple Flying's reporting, the FAA turned down requests from United, Alaska and Canadian North to loosen the compliance schedule, though it said it would consider individual extension requests backed by evidence.
On the line
Check 737NG fleet serial numbers against the bulletin's effectivity list now. The window to the 23 November 2026 compliance date is short, and any aircraft that reads high on the first freeplay check will likely need a repeat measurement rather than a single pass to clearance. Full background on the NG's structural history is on the 737 NG page.
Sources
- Federal Register, "Airworthiness Directives; The Boeing Company Airplanes", AD 2026-20-14, docket FAA-2025-5403, published 19 October 2026. https://www.federalregister.gov/documents/2026/10/19/2026-21333/airworthiness-directives-the-boeing-company-airplanes
- Simple Flying, "Nearly 2,000 Boeing 737s Must Get Tail Inspections After Jets Pitched Up And Down Mid-Flight", October 2026. https://simpleflying.com/nearly-2000-boeing-737-tail-inspections-faa/
- AeroTime, "FAA orders inspections of nearly 2,000 Boeing 737NGs", October 2026. https://www.aerotime.aero/articles/faa-boeing-737ng-stabilizer-inspections