ANA to replace all 100 Rolls Royce Trent 1000 engines on its Dreamliners

An in-flight, uncontained, engine failure not only trashes that particular engine, but can also send shrapnel into potentially vulnerable areas of the aircraft (wing fuel tanks for example). The aircraft may still be able to fly without that engine but the effects of shrapnel are potentially lethal.

Rolls Royce had its share of teething problems with its Trent 900 engine for the Airbus A380 (Trent 900 failures) and had to spend at least $300 million to replace faulty engines. There are only two engines from two manufacturers available for the A380 (Trent 900 from Rolls Royce and the GP7200 from the Engine Alliance – a 50/50 JV between GE and Pratt & Whitney), and competition is limited. Whereas the A380 has 4 turbofan engines, Boeing’s 787 Dreamliner has only two. Again competition is limited between Rolls Royce’s Trent 1000 and GE’s GenX.

But the Trent 1000 is having erosion/corrosion problems which are causing blades to crack. Blade failure is particularly nasty since the entire engine downstream of the failure can be easily wiped out. Worse, a broken blade or its fragments travel at high speed and can be ejected through the engine casing creating the “uncontained failure”. Vibration induced failures usually show up relatively quickly but corrosion/erosion induced failures can take a few thousand hours of operation to show up. In any event, the Japanese airline ANA has five affected engines but is replacing all 100 engines on its 50 aircraft.

The Guardian:The Japanese airline ANA has said it will replace all 100 Rolls-Royce engines on its fleet of Boeing 787 Dreamliners after three engine failures in 2016 caused by corrosion and cracking of turbine blades.

The world’s largest 787 operator said all 50 of its 787s would receive engines fitted with new blades, a process that could take up to three years.

ANA had five engines that currently needed repairs “but we will replace all the 100 engines for enhanced safety measures”, the company said, adding that it had already repaired three engines.

Rolls-Royce said the engine maker would swap existing blades for new ones on ANA’s planes in the short term, and had already started production of a new blade design that would be ready by the end of 2016.

ANA and Rolls Royce have not revealed which blade row is affected but it is thought to be due to the flaking of protective coating on the blades of the single stage intermediate pressure turbine. The Trent 1000 is a three-shaft engine with a 2.8m swept-back fan. A single stage LP compressor is followed by an 8-stage IP compressor and a 6-stage HP compressor. The turbine section consists of a single-stage HP, a single-stage IP and a 6-stage LP turbine. Corrosion/erosion is only an issue in the high temperature turbine sections and the HP and IP turbines are most likely to be affected rather than the 6 stages of the LP turbine. Certainly the HP and IP blades would be coated and presumably the bonding between the coating and the blades is an issue causing the coating to flake off and the base metal to be corroded. (Erosion if caused by corrosion products in the IP section could well appear in the downstream LP sections). Faulty coating is more likely to be a manufacturing or a materials issue rather than a design fault.

A permanent fix is expected by the end of this year. But Rolls Royce must have supplied some 300 – 400 Trent 1000 engines to the 445 Dreamliners delivered so far. With ANA as the precedent, all will have to be fixed or replaced. So the 2016 RR results will probably be hit by a substantial provision for fixing the issue.

With only 2 manufacturers available for the engines for the Airbus A380 and the B787 Dreamliner, the aviation industry needs their products to succeed and compete.

Tags: ANA, Rolls Royce, Trent 1000

This entry was posted on September 1, 2016 at 7:16 am and is filed under Aviation. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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ANA to replace all 100 Rolls Royce Trent 1000 engines on its Dreamliners

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