Boeing and Safran says they will design, build and service auxiliary power units (APUs), an onboard engine that is used to primarily start the main engines and power aircraft systems on the ground and, if necessary, in flight.

Both companies will have a 50 percent stake in the partnership, which will be based in the United States. The deal is expected to close in the second-half of 2018.

Safran currently supplies components to Boeing commercial and defense programs, including as a partner to produce CFM's LEAP-1B engine for the 737 MAX (through CFM International, a 50/50 joint venture between Safran Aircraft Engines and GE). Boeing and Safran also are partners in MATIS, a joint venture in Morocco producing wiring products for several airframe and engine companies.

An engine supplied by CFM International failed on a Southwest Airlines Boeing 737 during a mid-April flight from New York City to Dallas. The accident killed one passenger and forced the aircraft to make an emergency landing in Philadelphia.