GE Aviation has recalled its four GE9X compliance engines from Boeing. The four engines would be used to power the first flights of the 777X, but have suffered from unexpected wear in the high-pressure compressor. In order to ship the four enormous engines from Boeing's facility to GE's in Ohio, the air freight services of a huge Antonov AN-124 will be required.

777x engine
The GE9X engine that will power the Lufthansa 777X. Photo: Dan Nevill via Wikimedia Commons

The saga of the delays to the newest plane in the Boeing stable shows no sign of ending soon. After the first flight of the 777X was pushed back in June this year, due to issues with the engines, further details were revealed during the Paris Air Show that suggested the fix was not going to be easy. At that time, Boeing admitted it would be the autumn before the new bird would take to the skies, however, that has subsequently become unrealistic too.

In Boeings second-quarter earnings call, the planemaker admitted that the 777X was unlikely to take its first flight before the new year. This indicated that the problems with the GE9X engines ran much deeper than initially thought.

Today, we’re getting an indication of just how deep, as GE Aviation has apparently recalled four engines from Boeing in order to address the fault in detail.

GE recalls the GE9X engines

According to Flight Global, GE Aviation has recalled four powerplants from Boeing in order to address the known compressor issue. The four GE9X ‘compliance engines’ will be shipped to GE’s facilities in Ohio. According to Flight Global, GE commented that,

"The GE9X engines are the compliance engines that will be returned for the high-pressure compressor hardware enhancements that GE revealed at the Paris air show. GE Aviation remains aligned with Boeing on this effort as we work toward first flight”.

Back at the Paris Air Show, GE Aviation executives talked to the press about issues with the GE9X engines. At the time, they discussed a problem with the high-pressure compressor, specifically a stator that was wearing much faster than they anticipated. GE said at the time it would need several months to work on the fixes.

Boeing 777X Close-Up
The composite fan of the GE9X engines is more than 11 feet in diameter. Photo: Boeing.

Simple Flying reached out to Boeing to see what impact this latest development could have on the timetable for the 777X entry into service. A Boeing spokesperson responded to us, saying,

“As GE announced at the Paris Air Show and we discussed during 2nd Quarter Earnings call, there were some challenges with the engine that were discovered during pre-flight testing. Therefore, Boeing is returning the first set of GE9X test flight engines to GE for retrofit.

“Boeing currently plans for first flight to take place in early 2020.”

So, it sounds like this is actually a positive thing, as it signifies GE is on track to implement their fix once the engines are received in Ohio.

A big engine needs a big plane

The news of the recall was first noted on the 19th of August when a filing to the US Department of Transport (DoT) came to light. The filing was issued by Russia’s Volga-Dnepr Airlines, who will be flying the four powerplants from Boeing Field in Washington state to Ohio. But why was a Russian airline applying for permission to move the engines?

The answer is simple – they’re massive. The 777-9 will feature the largest and most powerful engines ever seen on an aircraft, and at 13 feet in diameter (15 feet at the nacelle) they could literally swallow a 737 fuselage whole. When packed up on their stands, the application to the DoT states that they will occupy 8x4x4m of space, and will weight 36,000 lb. (16,300 kg).

GE9X engine size
The GE9X can swallow the fuselage of a 737. Image: GE

As no US airline has the ability to haul such enormous, heavy pieces of equipment, it was necessary to look for a suitable cargo aircraft to move them.

According to the filing, the airline will use an Antonov AN-124 to move the engines. This quad jet aircraft has been designed from the ground up to be a load shifter, and can carry up to 150 tons of cargo on board. It has 24 wheels, the ability to kneel to receive cargo and an onboard overhead crane suitable for lifting up to 30 tones and winching 120 tones.

Volga-Dnepr_Antonov_An-124
Volga Dnepr's AN-124 in action. Photo: Fran Jurado via Wikimedia

Volga-Dnepr has 12 of the Antonov AN-124s in its fleet, with three more on order. It plans to transport the engines and ancillary parts to GE within a months’ time, pending approval by the DoT. The airline has indicated than any delay to the application process could lead to a delay in the 777X development.