The Federal Aviation Administration (FAA) has issued a sweeping airworthiness directive ordering tail inspections on 1,987 US-registered Boeing 737 Next Generation (737NG) aircraft after multiple operators reported alarming incidents in which the planes’ noses moved up and down mid-flight — a dangerous condition known as pitch oscillation.
The directive, designated AD 2026-20-14, targets excessive movement — or “freeplay” — in the horizontal stabilizer pivot hinges and jackscrew at the rear of the affected aircraft. The FAA has warned that if left unaddressed, the issue could trigger an aerodynamic flutter event and potentially lead to a loss of control in flight. The order covers Boeing 737-600, -700, -700C, -800, -900, and -900ER models; the newer 737 MAX family is not affected.
Airlines will be required to measure excessive movement at the stabilizer pivot hinges and jackscrew, following Boeing Alert Requirements Bulletin 737-55A1104 RB, dated June 12, 2025. Depending on inspection results, operators may need to perform repeat checks, or repair or replace worn components. The total estimated cost of initial inspections across the affected fleet is approximately $1.01 million, not including any parts replacement costs.
The directive takes effect on November 23, 2026. Both United Airlines and Alaska Airlines had requested changes to the rule, but the FAA rejected all modification requests. The order currently applies only to the US register, though over 5,160 737NGs operate worldwide.