Just received a report from CFM in China, indicating that COMAC will announce next week, that the engine choice for the C919, would be the LEAP-X. I also received initial information from COMAC on the same.
COMAC when they release their tender for engine supplier has specification that the engine must offer a 15% fuel saving over existing engine types, and a NOX emission reduction of at least 50%. So far the LEAP-X is the only new engine development that matches such requirement.
However, if COMAC really announce the LEAP-X as winner, then there would be a time gap between C919 in-service date. The C919 test version can still be powered by CFM56 latest model, and will then be retrofit with LEAP-X for certification after 2016. Initial production lot would then be powered by CFM56, and then subsequent lot be powered by the LEAP-X.
The engine choice will means that the C919 design would be over, and construction of prototype would begin in China shortly.