Boeing Co. (NYSE: BA), the world's second-largest aircraft maker after EADS unit Airbus, shocked its customers and investors, by announcing it would be pushing back the delivery date of its first 787 Dreamliner by several weeks, to around the middle of the first quarter of 2011.

Boeing said, Thursday, the postponement is due to delay in the availability of a Rolls-Royce (LON.RR) engine -- Trent 1000 -- needed for the final phases of flight testing of the carbon-composite aircraft.

"The delivery date revision follows an assessment of the availability of an engine needed for the final phases of flight test this fall," Boeing said in a statement late Thursday night. "Flight testing across the test fleet continues as planned."

Boeing spokeswoman Yvonne Leach said the company is working closely with Rolls-Royce to expedite engine deliveries.

Boeing is using Rolls-Royce Trent engines in four of its six flight test aircraft. General Electric (NYSE: GE) supplies its GEnX engines for the remaining two test aircraft.

This is the sixth delay Boeing has announced relating to the production of the Dreamliner.

Boeing had unveiled the Dreamliner in July 2007 and had received more than $100 billion in orders from customers who were promised by the U.S. aircraft manufacturer that the midsize, long-haul aircraft will be able to maximize their profits as it burns less fuel, is cheaper to maintain and offers more passenger comforts than comparable planes flying today.

The Dreamliner, being built in Seattle, is the world's first large commercial airplane made up of 50 percent carbon composite materials and another 15 percent titanium, making it much lighter and fuel efficient than existing jetliners of the same size.

The twin-engine aircraft, which seats nine-abreast in coach, can carry 210 to 330 people in its three models of various sizes. Prices range from $146 million to $200 million depending on the model.

Boeing had received nearly 850 orders for the Dreamliner and was scheduled to begin production of the Dreamliner in May 2008 and deliver the first batch of 55 aircraft to Japan's All Nippon Airways (ANA) in late 2010.

However, parts shortage, design problems and workers strike had forced the company to delay production five times in three years and postpone the first test flight six times.

In July, the company said a problems with the "horizontal stabilizer" and instrumentation delays could push back the first delivery date into next year.

Boeing did not say whether the latest delay was related to an accident at a Rolls-Royce engine test site in Derby, England. On August 2, a Trent 1000 engine blew up at the company's test site, significantly damaging the engine and the casing that houses it. The event forced Rolls-Royce to temporarily shut down the facility for repairs.

However, Rolls-Royce said, Thursday, the engine supply issue is not related to the "test bed event which occurred earlier this month." The company said it has never faced any delay in supply of engines before and is working closely with Boeing to expedite delivery of the engines.

"It is probable that some modification will be required to the Trent 1000's already on the 787 test certification program," said BGC Partners analyst Howard Wheeldon.

Nonetheless, analysts warn that the latest delay could exasperate customers into canceling their orders.

"The plane is a show-me plane at this point and I think everyone knows that," said Alex Hamilton, managing director with boutique investment bank EarlyBirdCapital. "I'll believe it when I see it."

Earlier delays had prompted airlines such as Russia's S7 and Australia's Qantas to cancel their orders last year. Since the beginning of 2010, Boeing has received 32 cancellations for its Dreamliner and just 28 new orders.

The string of delays has also prompted some airlines like Virgin Atlantic and India's Air India to demand compensations.

Deutsche Bank analyst Miles Walton told Bloomberg late penalties payable by Boeing to 787 customers may have already reached $5 billion.

However, analysts believe any compensation deals would be settled through aircraft discounts and maintenance agreements, options and purchase rights, rather than cash payments.

ANA said, Friday, the latest news of the latest delay was "regrettable" and expects Boeing to meet its March 2011 deadline. The delay, however, will not impact ANA's operations or its full-year earnings, the Japanese carrier said.

Analysts also said delays on such huge industrial programs are not uncommon. Development of rival Airbus' A380 super-jumbo was also dogged by problems, plunging the manufacturer into heavy losses and forcing a clear-out of management, analysts said.

According to Jefferies & Co. analyst Howard Rubel, though Dreamliner production program has turned out to be more problematic than expected, there is little doubt the aircraft will ultimately be certified and meet customer expectations.

"The test of how good the plane is going to be will be determined by its in-service performance," Rubel said in a research note to clients.

At 12.01PM (EDT), shares of Chicago, Illinois-based Boeing were trading up 2.72 percent at $62.99 on the New York Stock Exchange. Shares of Rolls-Royce closed down 0.63 percent at 555.50 pence on the London bourse.

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