LONDON, Feb 29 (Reuters) - Emirates Airlines President Tim Clark expressed doubts on Thursday about whether the company would get its order of Boeing aircraft by the end of next year and said the U.S. planemaker needed to "make changes".

His comments come as airlines have complained of delivery delays from Boeing as it grapples with quality issues and a regulatory crackdown following the blowout of a panel on one of its MAX 9 jets during a flight on Jan. 5.

"The 777X (delivery) is probably at the back end of next year and maybe 2026, if we're unlucky," Clark said at an industry lunch in London.

The 777X delivery to Emirates was initially expected in 2020, and after successive delays was pushed back to October 2025.

"Clearly, there are issues there," Clark said of Boeing, adding that broader supply chain challenges were slowing production at Airbus as well.

Clark added that Emirates Airlines will not buy Airbus planes with Rolls-Royce's Trent XWB-97 jet engines until it is convinced they are durable.

After previous concerns from Clark, Rolls-Royce had said last year that it was taking steps to improve the durability of the engines, with Clark adding that Rolls-Royce's CEO had promised to spend "a billion pounds or something to try and sort the engine out."

Clark later told journalists that Boeing needs to make changes, stopping short of calling for a revamp of its governance.

"The (U.S. Federal Aviation Administration) said there was a disconnect between the management and the safety system. All this is something that some of us have been saying for a long time," Clark added.

Boeing was not immediately available to comment.

Clark's comments echo those of Ryanair CEO Michael O'Leary, who has called for changes in Boeing management in Seattle, but has thrown his support behind Boeing CEO Dave Calhoun and CFO Brian West.

Despite the criticism of the planemaker, Clark said the "whole situation is salvageable," adding that good technology and vision will put Boeing in as strong a position as they were in before.

(Additional reporting by Allison Lampert, Sachin Ravikumar and Muvija M; Editing by Bill Berkrot)