(Bloomberg) -- Boeing Co. 787 Dreamliner planes equipped with a batch of potentially faulty Rolls-Royce Holdings Plc engines face restrictions on how far they can fly following a ruling by the U.S. Federal Aviation Administration.
The measure, which Boeing has said affects about a quarter of in-service 787s, restricts the planes from operating more than 140 minutes from a diversionary airport, down from 330 minutes currently, the FAA said in a post in the Federal Register on Monday.
The move comes after the European Aviation Safety Agency last week ordered additional maintenance checks on Trent 1000 “package C” engines after it was found that durability issues afflicting blades were worse than first thought. About 350 turbines will be affected, according to London-based Rolls.
“The directives mandate action that Boeing and Rolls-Royce previously recommended to the fleet, including additional inspections of the intermediate pressure compressor blade at certain cycles and operational changes,” Boeing said in a statement. “The exact impact is dependent on how airlines choose to operate the airplane.”
The FAA imposed the restrictions because the affected blades on the Trent 1000s have been found to vibrate at high levels of thrust under certain conditions. That means a 787 on which one engine failed might face having the other malfunction when tuned to maximum thrust in order to compensate.
The regulator described the engine as involving “an unsafe condition” requiring the “immediate adoption” of new rules. The directive will be re-assessed once Rolls has presented a fix for the fault, it said.
About 14 U.S. planes are affected, the FAA said. Foreign planes with the engines may also be serving U.S. airports.
EASA is responsible for safety regulation of Rolls-Royce as a U.K. company, whereas the FAA has oversight of Chicago-based Boeing as a U.S. one.
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