Complex sentence: The RAF's Future Strategic Tanker Aircraft, the Airbus A330 MRTT, will be based at Brize Norton to replace the VC-10 and Tristar tanker fleets.
Split into simpler sentences: The RAF's Future Strategic Tanker Aircraft, currently envisaged to be a fleet of Airbus A330 MRTTs, will be based at Brize Norton. This aircraft will replace the VC-10 and Tristar tanker fleets.