FAA Mandates Inspections for Nearly 2,000 Boeing 737NG Aircraft

The Federal Aviation Administration (FAA) has issued a new directive requiring inspections for almost 2,000 Boeing 737NG aircraft registered in the United States. This action comes after reports of unexpected pitch oscillations occurring during flights. The directive, Airworthiness Directive 2026-20-14, was published on October 19, 2026, and will take effect on November 23, 2026. This order specifically targets the 737-600, -700, -700C, -800, -900, and -900ER models, while the newer 737 MAX series is not included.

Understanding the Pitch Oscillation Issue

The core of the FAA’s concern lies with multiple reports from aircraft operators detailing nose-up and nose-down movements during flight. These oscillations are linked to excessive play or looseness in the horizontal stabilizer, a critical component that controls the aircraft’s pitch attitude. While the FAA has not specified when or where these events occurred, or which airlines were involved, the potential consequences are serious. The agency warned that if this unsafe condition is not addressed, it could lead to a flutter event, potentially resulting in a loss of control of the airplane.

Inspection Procedures for the Horizontal Stabilizer

To address the identified issue, the FAA’s directive mandates specific inspection procedures. Inspectors will need to measure the amount of freeplay at the hinges and the jackscrew of the horizontal stabilizer. The jackscrew is the mechanism that moves the horizontal stabilizer to adjust the aircraft’s pitch. These measurements will determine if further checks, repairs, or component replacements are necessary.

The inspection process is detailed in Boeing’s Alert Requirements Bulletin 737-55A1104 RB, which was issued on June 12, 2025. Some aircraft may also require repeat measurements at intervals specified by the FAA’s directive. This proactive approach aims to catch potential problems before they escalate into safety hazards.

Airline Feedback and Potential Workload Adjustments

Airlines operating affected aircraft have provided feedback and requested adjustments to the directive’s requirements. United Airlines, with over 300 affected aircraft, has asked for extended intervals between repeat inspections and credit for checks already performed. They also requested longer intervals for aircraft that have had replacement hinge bearings installed compared to those still using original parts.

Canadian North has proposed extending the initial inspection threshold from 12 months to 36 months, allowing the work to be completed during scheduled heavy maintenance visits. Alaska Airlines has requested permission to perform immediate repairs on worn parts rather than conducting interim freeplay checks. These requests highlight the operational considerations for airlines in managing maintenance schedules and costs.

Estimated Costs and Compliance Schedule

The FAA estimates that the measurement portion of the inspection will take approximately six work-hours per aircraft, costing around $510, assuming a labor rate of $85 per hour. This brings the estimated initial inspection cost for the entire U.S. fleet of affected aircraft to about $1 million. It is important to note that these estimates do not include the costs associated with any necessary repairs or replacement parts. The agency has not yet determined how many aircraft will require these additional services or the cost of those components.

Aircraft operators are advised to consult the compliance schedule within AD 2026-20-14 to plan their inspections and any subsequent maintenance. The detailed inspection procedures can be found in the Boeing bulletin dated June 12, 2025. Adhering to this schedule is essential for ensuring the continued airworthiness of the Boeing 737NG fleet.

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