This afternoon, Flightblogger tweeted that ZA001 is grounded in Roswell, NM due to an engine problem. Boeing is saying ZA001 experienced an engine surge on September 10th and that they have a replacement engine on site and are working to replace the engine.
In his tweet, Flightblogger said that ZA001 should be flying back to Boeing Field either on Friday or Saturday. Boeing is working with Rolls Royce to determine the root cause of the engine surge and implement a fix.
Impact to the test schedule is not known at this time but there may be no impact at all.
This aircraft is equipped with the package “A” Trent 1000 engines, the same type that had an uncontained failure on an engine test stand in Derby, UK. The engine that was on ZA001 didn't have an uncontained failure and Boeing siad that the engine surge is unrelated to the engine failure on August 2nd.
Sources have told me that the aircraft experienced the surge in the right engine. The ZA002 and ZA003 are in planned ground test right now and ZA004 and ZA005 are in planned layups.
UPDATE: Sources have told me that ZA004, which will swap out its package "A" Trents for the package "B" Trents will have its engine swap starting on November 16th. The swap should take about three weeks followed by one more week of ground tests. ZA004 should be back in the air with the package "B" Trents around Decm. 14th...close to the one year anniversary of the first 787 flight.
Flightblogger: Breaking: Boeing grounds ZA001 following engine surge
Bloomberg: Boeing Says 787 Test Jet Grounded Due to Engine Surge
Guy Norris: Boeing 787 Suffers Engine Surge During Flight Tests