WASHINGTON, Sept 10 (Reuters) - The head of European

planemaker Airbus said novel open-rotor technology

being tested by engine maker CFM International offers promising

efficiencies and reductions in emissions but that the "jury is

out" on whether it will be viable.

Chief Executive Guillaume Faury also told reporters on the

sidelines of the Global Aerospace Summit, hosted by the U.S.

Chamber of Commerce, that deliveries of the current generation

of LEAP engines built by CFM International continue to be late.

"They are late in their deliveries," he said.