United will still fly the Boeing 777-200 after a scary engine failure in Colorado - but the ones still flying have a different engine

• United Airlines' fleet of 24 Boeing 777-200 aircraft has been grounded by the Federal Aviation Administration, but the aircraft will keep flying.
• A fleet of 22 United Boeing 777-200s are unaffected as they're powered by General Electric engines.
• Passengers booked on the 777 might still fly on the aircraft but others will be moved to different jets.

The Federal Aviation Administration has effectively grounded United Airlines' fleet of 24 Boeing 777-200 aircraft powered by the Pratt & Whitney PW4000-112 engine that failed on Saturday during a flight from Denver to Honolulu.

An airline spokesperson told Insider that the extent of the grounding remains to be seen as the agency has not yet issued an airworthiness directive, or AD, outlining the inspections that the airline needs to perform before the engine can return to the skies.

Flyers that still see "Boeing 777-200" for their United flights in the next few days, however, need not be concerned as their flight will be operated by a different type of 777 aircraft, one powered by General Electric engines. This grounding only affects the 777s powered by Pratt & Whitney engines and not the entire 777 fleet, which experts say has a track record of safety.

United has 22 General Electric-powered 777-200s currently flying that will serve destinations like Tokyo, Japan; San Juan, Puerto Rico; Milan, Italy; and Kahului, Hawaii, among others. The Pratt & Whitney engines were initially purchased by United to power its Boeing 777s but the airline acquired General Electric-powered 777s after a merger with Continental Airlines.

It's common that airlines acquire new aircraft with different engine types in a merger, but airlines typically stick to one type of engine per plane.

"Airlines like commonality, it leads to simplification," Henry Harteveldt, founder of travel research company Atmosphere Research Group, told Insider.

United's Boeing 777-300ER aircraft, similarly powered by General Electric engines, will also remain in the skies. The variant is the largest of the 777 family currently in commercial service and also flying for the likes of American Airlines, British Airways, and Qatar Airways.

Flyers might also see their aircraft changed as their departure date moves closer as United deals with the short-term impacts of the grounding on its schedule. United's wide-body fleet includes newer jets like the Boeing 787 Dreamliner family, in addition to the 777-300ER.

The FAA will likely release its airworthiness directive this week, and that's when the extent of the grounding will be known. United may be forced to restore aircraft from storage if the grounding is protracted but the airline said it hasn't needed to cancel any trips due to the incident; though, some delays have been incurred as replacement aircraft move around the airline's network.