Rolls Royce 787 Engines Have A Huge Problem

The Boeing 787 began service with Japanese airline ANA or All Nippon Airways. ANA was immediately impressed with the performance of the 787, so much so that the company became the top operator of the Dreamliner. However, aircraft service with the 787 has not been smooth sailing over it's life. 

I was part of the design team on the Boeing 787, and every time we saw an issue crop up, I'd quickly make sure it had nothing to do with the work I was responsible for, and to date my areas of the plane have been unaffected. The plane however has seen some significant pains in the days since it entered production. Battery issues grounded the fleet for a time, much of that being a direct result of incidents on board Japanese carriers. That issue has since been resolved.

Now it looks like ANA has discovered a big issue that impacts their fleet. Rolls Royce engines are susceptible to turbine blade cracking and subsequently high vibration from the damaged engines. This is not an issue that impacts all 787 aircraft though and there is a reason for that. 

When purchasing a new 787 aircraft, there are two engine options to choose from. Companies have a choice between Rolls Royce engines and General Electric engines. Only about 40% of customers choose the Rolls Royce engines and there is a good reason that GE has the majority of customer, they put a lot of work into making their engines easier to repair and less complicated. Rolls Royce stuck with past design choices and made their normal, more complicated engines. With more complication, comes more difficult repair and more chance for failure.

The big difference in design between the two engines is that GE uses a two stage engine and Rolls uses a 3 stage engine. This means that Rolls Royce has more moving parts, additional drive systems, and overall the engine is heavier. Also, Rolls Royce doesn't use the GE quick change out system either making repairs and getting planes back in the air more difficult and slower. All of this looks to be contributing to a major problem for ANA and likely other airlines as the problem looks to affect more than just ANA. ANA is currently saying that the repair fleet wide could take as long as 3 years to complete, quite a hefty investment in time to fix a manufacturing/design problem.

ANA currently operates fifty 787 aircraft, many of which need to have the turbine stages replaced. Turbine blades are at the aft end of a jet engine and see the highest temperatures of any engine part. After combustion, the hot gases escape through the turbine blades which power the rest of the engine. Since the turbine blades see very high temperatures, this can make them susceptible to a range of failures if not properly designed. 

ANA has not been forthcoming on what conditions cause the issue, but did state that there are certain conditions that can cause the problem, likely meaning that the issue is repeatable. It is unclear if this is a manufacturing defect on certain engines or a deeper design flaw in how the engine was made from the start.

While Rolls Royce claims that only engines operated by ANA are impacted, this is very very very hard to believe. 787's are not sold in blocks, Boeing does not sell the first 20 to ANA, and then 20 to Etihad and so forth, each Dreamliner created tends to go to a different customer depending on when the airline has negotiated delivery and plans for working the planes into their schedule. To say that only ANA is impacted is borderline ridiculous. I won't write it off completely, but I do fully expect this problem to grow in the coming months.

At this point it is early and likely still under investigation by the FAA and EASA. We may see an air worthiness directive from the FAA in the near future if the problem is big enough. This would require all aircraft to be serviced quickly and could spell deep problems for Roll Royce. Right now this is still speculation, but I do not think this problem will be isolated to ANA.