As expected, the U.S. Federal Aviation Administration (FAA) on Monday issued an airworthiness directive (AD) on 787-8 and 787-9 passenger jets from Boeing Co. (NYSE: BA) limiting the distance that some of the aircraft may fly from a diversionary airport. The affected aircraft use several models of the Rolls-Royce Trent 1000 turbofan engines. The AD becomes effective April 17.
The engines will be inspected more frequently to determine if there has been any damage to the intermediate pressure compressor (IPC) stage 2 blades resulting from blade vibration that “can result in cumulative fatigue damage that can cause blade failure and consequent engine shutdown.” Thus, “if the remaining engine already had cracked IPC stage 2 blades, the likelihood of the remaining engine failing will further increase before a diversion can be safely completed.”
Because the 787 is a twin-engine plane designed to travel long distances, the FAA requires that it meet “Extended-range Twin-engine Operations” (ETOPS) requirements for how far it can fly on a single engine in the event that one engine fails. Prior to this AD, a Rolls-Royce powered 787 was permitted to fly up to 330 minutes flying time away from a diversionary airport. The FAA today reduced that limit to 140 minutes.
According to Rolls-Royce, about 350 engines were affected by a similar ruling last week by the European Aviation Safety Agency (EASA).
The FAA ruling, published in the Federal Register on Monday, notes that a total of 14 U.S.-registered 787s are covered by the AD and the total cost to inspect the engines on all 14 planes is $1,190. That is not the big issue.
The bigger issue for Rolls-Royce and Boeing is how to replace engines that fail the inspections with a minimum of disruption to their airline customers’ routes and schedules. According to a report in The Seattle Times, repairing a faulty engine takes between 10 and 40 days, not including the time needed to transport the engine to the repair facility. Rolls-Royce is working on a permanent fix that it expects to have in place by early next year.