UPDATE 3-Boeing, union reach deal to end strike; shares jump

* Boeing shares close up 15 pct

* Union to vote on deal on Saturday

* If deal ratified, workers could return to work Monday

* Suppliers' shares rise (Adds date of vote, closing share prices)

By Bill Rigby

NEW YORK, Oct 28 (Reuters) - Boeing Co (BA.N) and its biggest union have agreed to a tentative deal to end the longest strike at the planemaker's plants in 13 years and halt revenue losses estimated at $100 million a day.

If the deal, backed by union leaders, is approved by members in a vote on Saturday, it will bring the 53-day strike to an end and reopen Boeing's Seattle-area factories that have been closed since Sept. 6.

Boeing shares jumped 15 percent, followed by some of its key suppliers, but are still down 45 percent this year.

The agreement, struck late on Monday after five days of talks with a federal mediator, hands Boeing's 27,000 assembly workers a 15 percent pay raise over the four-year life of the contract and gives the union more scope for challenging Boeing's use of outside contractors.

The International Association of Machinists and Aerospace Workers, or IAM, had initially wanted a 13 percent pay raise over three years and to rewrite certain language in the contract relating to outsourcing.

Both sides claimed victory.

"We won the battle and made some significant gains" on job security, said IAM, while Boeing said it had "retained the flexibility necessary" to manage its business.

Outsourcing has become the largest sticking point between the planemaker and its plant workers in the last few years, as Boeing has sent most of the production work on its new 787 Dreamliner overseas, and is focusing on assembling the plane at its largest Seattle-area factory.

If members of the IAM ratify the deal and return to work from Monday it will end the longest Boeing strike in more than a decade. The union walked out for 28 days in 2005 and 69 days in 1995.

RELIEF

News of the breakthrough came as a relief to aerospace companies worldwide, part of an increasingly globalized network of suppliers.