DUBAI  - Emirates doubts it will receive any of the 115 Boeing 777-9s it has ordered next year, its president said on Monday, as the U.S. planemaker grapples with challenges in building the jet.

Emirates, a launch customer of the world's biggest twin engined jet, was to receive its first 777-9 in 2020 but the manufacturer has suspended load testing of the plane.

"... By the end of next year we were to have eight of them. Now it doesn't look like we will have any," Tim Clark said at a conference in Dubai.

Boeing suspended load testing of the new widebody in September when media reports said a cargo door failed a ground stress test. There have also been issues with General Electric Co’s new GE9X turbine engine that will power the jet.

Boeing has said it expects to hold the initial flight test in 2020 and is aiming for the 777X to enter commercial service in the same year.

Clark said he had told Boeing he insists on a 13 to 16 month test period for the new jet.

Emirates ordered 150 777X jets, including 777-8 variants, in 2013. It later placed a preliminary order for 40 Boeing 787 Dreamliner jets in 2017, which Clark said he still saw a place for in the airline's fleet plans.

Boeing has also been unable to deliver any of its 737 MAX aircraft since the single-aisle plane was grounded worldwide in March after two fatal crashes in Indonesia and Ethiopia killed 346 people.

Clark said in September Emirates would not take new Airbus AIR.PA and Boeing planes unless they were truly ready, and said that engine makers Rolls Royce RR.L and GE must improve their reliability.

Aircraft manufacturers should not over promise on new aircraft capability, he said on Monday.

Emirates has also signed deals for 40 Airbus A330-900s and 30 A350-900s.

(Reporting by Alexander Cornwall; Editing by Toby Chopra) ((alexander.cornwell@tr.com))