The GE90 series are physically the largest engines in aviation history, the fan diameter of the GE90-115B, has a fan diameter of 325 cm (128 in). As a result, GE90 engines can only be airfreighted in assembled form by outsize cargo aircraft such as the Antonov An-124 Condor, presenting unique problems if due to emergency diversions, a 777 was stranded in a place without the proper spare parts. If the fan is removed from the core, then the engines may be shipped on a 747 Freighter.[2] Apart from its size, the GE90-115B is powerful enough to fully operate GE's Boeing 747 testbed on its own power during a maximum thrust low speed flight testing on board the aircraft