FAA Proposes Mandatory Fan Cowl Fix on Boeing 787s Powered by Rolls-Royce Trent 1000 Engines Over Dual Engine Shutdown Risk

The FAA has proposed a mandatory airworthiness directive requiring fan cowl modifications on 22 US-registered Boeing 787s with Rolls-Royce Trent 1000 engines, citing dual engine shutdown risk.

Original report
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Industry impact

The case shows how a certification-review finding, not an accident, can still trigger fleet-wide inspection and parts-replacement obligations across widebody operators.

What happened

The Federal Aviation Administration has proposed a mandatory airworthiness directive requiring fan cowl modifications on select Boeing 787-8, 787-9, and 787-10 aircraft fitted with Rolls-Royce Trent 1000 engines, citing the risk of a dual engine shutdown in flight.

Boeing determined that the left fan cowl on the right engine does not provide adequate protection for several oil lines against debris that could be released during an uncontained rotor failure in the left engine. The FAA warned that such debris could damage the right engine and potentially cause both engines to shut down mid-flight. The FAA estimates 22 US-registered aircraft would be affected. Boeing flagged the issue to the FAA and on February 19 issued a Special Attention Requirements Bulletin detailing required inspections and modifications for the affected aircraft.

Under the proposed directive, operators must review maintenance records or physically inspect the right engine's left fan cowl to determine whether one of three affected part numbers is installed. Aircraft found with an affected fan cowl would then require modification or replacement of the part, and the directive would prohibit installing affected fan cowls on aircraft that do not already have them. The FAA estimates the initial records check or inspection will take three work hours per aircraft at a cost of USD 255 per unit, totaling USD 5,610 for all 22 affected US-registered aircraft; no cost estimate was provided for the subsequent modification or replacement work. The proposed rule stems from a certification concern rather than any accident or in-flight incident involving the 787, and comments are being accepted through September 21.

Who this affects

• Maintenance Repair and Overhaul (MRO) — Heavy maintenance shops face added inspection and part-replacement workscope on Trent 1000-powered 787s once the directive is finalized.
• Business Charter Operators — Operators of Trent 1000-powered 787s face a records check or inspection requirement and possible downtime for fan cowl modification.
• Aircraft Finance & Leasing Companies — Aircraft financing firms holding Trent 1000-powered 787s face an unresolved compliance cost tied to the proposed directive.