When airlines purchase brand-new aircraft straight from the manufacturer, they usually have multiple engine options to mull over. Variations in engine choice allow carriers to make strategic decisions and purchase planes tailored to their specifications. But what happens if an airline wants to change engines after it has taken delivery?

Switching engine manufacturers is rare

After an aircraft has been configured to a particular engine, it is both difficult and costly to change the engine to a completely different manufacturer. For example, if Emirates were to look at switching its Rolls-Royce engines to Pratt & Whitney, the process would likely prove far too uneconomical. Although it can be done, it usually won't be worth the cost and effort for all parties involved.

Rolls Royce, XWB-84, Engine Wear
Major structural and electrical changes make switching engine manufacturers uneconomical. Photo: Getty Images

Changing engines to an entirely new manufacturer necessitates major changes elsewhere across the plane, including the mounting pylon, wiring/ducting, instrumentation, and avionics systems. For these reasons, it is extremely rare for an aircraft to switch engine manufacturer after it has been delivered. It has been done before, but in almost all cases it wouldn't be economical for airlines or manufacturers to carry out such a procedure.

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Same-manufacturer engine changes are much easier

Upgrading engines is a relatively straightforward process, so long as it's from the same manufacturer. Engine companies like Rolls-Royce and General Electric are always improving their engines, with newer models offering improvements in key areas like fuel efficiency and speed. As such, airlines will be eager to equip these new engines and make long-term savings, provided the switch is economical.

Airbus engine at maintenance
The maintenance crew left the metal piece in the engine after a regular check-up. Photo: Getty Images

Changing engines can still be costly, but airlines and lessors can get favorable deals on engine maintenance/switching if they have an agreement in place. Engine manufacturers are increasingly offering original equipment manufacturer (OEM) contracts. This agreement means maintenance and repair work will be handled by the manufacturer rather than by the airline or a third-party.

Comac C919
The CFM LEAP-1C engine is a joint venture between GE and Safran. Photo: Getty Images

Under an OEM agreement, engine companies may perform a complete switch of engine, but it all depends on the nature of the agreement. In the event of faulty engines, manufacturers will be bound to switch out engines if necessary, but upgrading to a new, more-efficient engine-type would only be covered if included in the agreement. Otherwise, airlines will be fronting the full cost of the replacement themselves.

Some engine changes are mandatory

There have been many cases where airlines are forced to change engines due to mechanical issues. The most high-profile case in recent times involved Rolls-Royce and its Trent 1000 engine. The Trent 1000 originally had problems with premature wear in its engine blades before Rolls-Royce addressed the issue.

Rolls Royce
Rolls-Royce changed hundreds of engines after issues with the Trent 1000 engine. Photo: Getty Images
Air is diverted from the engines into the cabin. Photo: Getty Images

However, further problems were discovered in 787 Dreamliner Trent 1000 engines, forcing the EASA to issue an airworthiness directive. In response, Rolls-Royce carried out engine changes for some of its customers, including over 100 engine changes for Virgin Atlantic's fleet of 787s.

Have you ever worked on replacing an aircraft engine? Feel free to share your insights in the comments.