After notching two jet fighter contracts, Boeing could be turning the page

(Updates headline to remove the word 'Naval,' no changes to text.)

SEATTLE, Oct 5 (Reuters) - Boeing's won the contract for the US Navy's next-generation fighter due to years of investment, decades of experience building carrier-based jets and a design approach that closely matched the Pentagon's push for ‌easier-to-upgrade aircraft, according to people familiar with the competition.

Last week's win marks Boeing's second major fighter jet victory after securing the Air Force's F-47 program ‌last year. The aerospace company bested rivals Lockheed Martin and Northrop Grumman for the Navy's F/A-XX fighter contract, worth more than $20 billion in its initial development phase.

The victories give the company's defense, space and security ​division an opportunity to turn the corner on years of costly overruns, delays on military aircraft programs and the high-profile setbacks of its Starliner spacecraft.

"Now all of a sudden, it controls the next half century and beyond of US tactical aircraft," said Richard Aboulafia, managing director of AeroDynamic Advisory. "There's nothing like that in history."

The Pentagon required competitors for the F-47 and F/A-XX programs — Boeing, Lockheed Martin and Northrop Grumman — to use common design standards to make later upgrades and modifications easier, in order to respond quickly to changing technology and evolving ‌threats.

"All the industry players did what they were supposed to, ⁠but there were varying degrees of embrace and enthusiasm," said a former Pentagon official familiar with the competitions. "Boeing's embrace was effective."

The company also distinguished itself through its use of digital design tools, making it easier for engineers, military officials and maintainers to test changes ⁠and refine the aircraft during development, the official said.

The Pentagon and Lockheed Martin declined to comment.

Northrop Grumman said in a statement that it "offered a highly survivable, digitally advanced sixth-generation fighter" in the F/A-XX competition, and it has "requested a debriefing from the US Navy" on the selection process and award decision, a requirement for appealing the Pentagon's decision.

Winning the programs does ​not ​guarantee financial success for Boeing. Several analysts said the outcome will depend heavily on the terms ​of the contracts, which neither Boeing nor the Defense Department would ‌comment on.

Boeing has lost $20.5 billion on five fixed-price development programs that left it responsible for cost overruns — the KC-46 tanker, T-7 trainer, MQ-25 refueling drone, Air Force One replacement and Starliner programs.