ZA004 to get Trent package"B" engines later this month

Sources have confirmed to me that Boeing will be re-equipping ZA004 with the improve package "B" version of the Trent 1000 engine later this month. That engine has been undergoing testing on Rolls Royce's 747 engine test bed as well as at RR's engine test facilities for sometime now but installation on ZA004 was put off due to the fire on ZA002. Guy Norris summed up the package improvements nicely in an article from last September:

Rolls-Royce’s Trent 1000 built to the improved ‘Package B’ standard is designed to bring performance to within 1% of Boeing’s original specification. Package B includes enhanced aerodynamics in the six-stage low pressure (LP) turbine, improved cooling flow for the IP turbine and changes to the secondary air system to take off sealing and cooling air at a lower pressure stage. The root-to-tip twist of the fan blade is also slightly altered to match changes in the pressure ratio caused by a concurrent reduction in nozzle area. Rolls has run at least three Package B performance engines and, when last reporting on progress, says all were in line with expectations. In March Rolls was flight testing the first Package B engine on its company 747 flying testbed ahead of delivering finalized engines to Boeing for installation on ZA004.

ZA004 is scheduled to receive the engines over a two week period (Feb. 23rd to March 11th). Previously, the installation and ground testing was to take about a month before resuming flights with the improved engines. If that schedule holds true this time around, then we could see ZA004 returning to the skies with the new engines around the last week of March. It will undertake much of the same testing that the 787 program conducted using the Trent 1000 package "A" as well as conducting ETOPs testing with the improved package "B" engines.