NEW YORK (Reuters) - Boeing Co's (BA.N: Quote, Profile, Research) chief executive has admitted that the company's ambitious plan to outsource most of the production of its new 787 Dreamliner jet has not been completely successful and could lead to a re-evaluation for future programs.

The admission is the clearest indication yet that Boeing's revolutionary plan to parcel out production of most of the carbon-composite aircraft to suppliers around the world has aggravated problems on the program, which is now running 15 months behind schedule.

"The global-partnership model of the 787 remains a fundamentally sound strategy," said Boeing CEO Jim McNerney in a memo circulated to employees on Monday. "But we may have gone a little too far, too fast in a couple of areas. I expect we'll modify our approach somewhat on future programs -- possibly drawing the lines in different places with regard to what we ask our partners to do."

The memo was published online by industry blog FlightBlogger (http://www.flightglobal.com/blogs/flightblogger/), run by aviation enthusiast Jon Ostrower. Boeing confirmed the authenticity of the memo but declined to comment further.

McNerney's message, entitled "Time to deliver on the 787," comes shortly after Boeing announced the third major delay on the aircraft, which has not yet left the ground for tests almost a year after major assembly of the first plane started.

The Chicago-based company shook up the industry and upset some of its own employees five years ago when it announced a plan to hire outside companies to build most of the 787 and ship the parts to its Seattle-area plant for assembly, instead of making more of the plane itself.

OFFLOADS RISK

The plan, which offloads some of the financial risk of developing the plane to its main partners in Japan, Italy and elsewhere, was hailed as the future of aircraft manufacturing by some, but dismissed as mere cost-cutting by others. Naysayers felt that Boeing may have given up too much control of the manufacturing process.

Some of those fears have been realized, as suppliers have struggled to deliver finished work to Seattle, forcing Boeing employees to do more of the work themselves in a plant that was only designed for assembly.