The Federal Aviation Administration (FAA) has issued a superseding airworthiness directive (AD) for the Rolls-Royce Trent 1000 that powers the Boeing 787 Dreamliner.

This AD replaces a previous one (AD 2018-25-01) released in 2018. The old one required initial and repetitive inspections of the intermediate-pressure compressor (IPC) stage 1 rotor (R1) blades, IPC stage 2 rotor (R2) blades, IPC shaft stage 2 dovetail posts, and removing any cracked parts from service.

FAA Issues Airworthiness Directive For 787 Engine
RR Trent 1000 Cutaway

The new AD retains those inspections, revises certain re-inspection intervals and adds certain engine models to the applicability; it was prompted by reports of IPC rotor blade cracks, which could lead to rotor blade separations resulting in engine failures. This unsafe condition, if not addressed, could result in failure of one or more engines, loss of thrust control, and loss of the airplane

FAA estimates that inspecting IPC blades and dovetail posts has a cost of $1700 (20 work-hours × $85 per hour).

FAA Issues Airworthiness Directive For 787 Engine
RR Trent 1000

Based on the results of the inspection, some engine parts may require replacement and some of these can be very significant.

For example to replace the IPC R1 blade, the FAA estimates this at 128 work-hours plus a part cost of $1,528; bringing the total to $12,408. But if the company needs to replace the IPC 1-8 drum, the FAA estimates this at a total of $1,384,259.

The AD will come into effect on 11th September 2019, inspections of any affected IPC part have to be completed within 15 days of the effective date.

This directive is valid for all RR Trent 1000-A, 1000-C, 1000-D, 1000-E, 1000-G and 1000-H engines.

These engines can be found in all of the Rolls-Royce powered 787 Dreamliners in service today.