Report: Mitsubishi Floats Building 777X Wings in Japan

Japan's Mitsubishi Heavy has suggested significant cost savings as part of a behind-the-scenes proposal to Boeing to build the wings of its next jetliner in Japan, a person with knowledge of the proposal said.

Details of the unsolicited proposal emerged on the eve of a crucial vote by 31,000 Boeing workers on a contract that may determine whether the 777X is built in Washington state, the home of nearly all Boeing's commercial jet manufacturing.

Boeing has said that if its machinists reject a proposed eight-year labour pact it will open talks with alternative locations for the assembly of the jet's fuselage and wings.

With Seattle-area workers given a first chance to vote on plans for a new jetliner, discussions between Boeing and other potential partners have not yet started and no concrete offer is on the table, several people close to the process stressed.

But Mitsubishi Heavy, which already makes wings for the 787 Dreamliner, has outlined to Boeing in detail how a new plant could be built alongside its existing 787 wing fabrication facility in the Japanese port city of Nagoya, the person said.

It has also presented a detailed blueprint that sets out significant cost savings by transforming the way in which the advanced carbon-composite wing panels are transported.

According to the person with knowledge of the plan, Mitsubishi has proposed building a fleet of five 'Roll On-Roll Off' cargo ships capable of transporting sections of the 777X wing, which would be the longest Boeing has ever commissioned.

This would be significantly cheaper than the current system of outsized "Dreamlifter" aircraft used to transport 787 wing panels, according to the person familiar with the proposal.

Mitsubishi and Boeing declined to comment.