Airworthiness Directives: The Boeing Company Airplanes

What it does

• •Requires operators of Boeing 747-400 and 747-400F airplanes to perform a maintenance records check or inspection for alternating current motor pumps (ACMPs) with part number 731966.
• •Mandates replacement of affected ACMPs with approved substitute part numbers (3033115-100, 66133-06, 66068-08, or later approved equivalents) if inspection reveals the defect.
• •Prohibits installation of affected ACMP part number 731966 on these aircraft models.

Why it matters

• •An ACMP with the affected part number can overheat and ignite a fire in the main landing gear wheel well if a critical component (lock washer and nut) is missing from an electrical control unit, potentially causing loss of safe flight and landing capability.
• •The airworthiness directive addresses a known unsafe condition already identified in similar Boeing 777 aircraft through an earlier adopted rule (AD 2026-19-04).

Who is affected

• •Operators and owners of Boeing 747-400 and 747-400F series airplanes, estimated at 105 aircraft of U.S. registry.
• •Boeing and maintenance service providers performing inspections and replacements on these aircraft.

What happens next

The FAA will accept public comments on this proposed airworthiness directive until December 28, 2026, and may amend the proposal based on substantive comments received before issuing a final rule.