Adds context, file photos of Wichita facility

By Allison Lampert and Utkarsh Shetti

Feb 10 (Reuters) - Spirit AeroSystems SPR.N expects to post higher-than-expected quarterly revenue, helped by production restarting at its biggest customer Boeing BA.N after a crippling strike, the U.S. aerospace giant said on Monday.

Spirit Aero also surprised in early results by saying it generated $91 million in quarterly free cash flow, as opposed to an expected usage, but company filings reveal challenges.

The Wichita, Kansas-based aerostructures giant said it has total financial liquidity of $890 million but expects to burn $650 million to $700 million in free cash during the first half of 2025, without offering an explanation.

The company's financial strain has put pressure on Boeing to complete its planned acquisition of the former subsidiary it spun off 20 years ago by mid-2025, in a complex deal involving its European rival Airbus AIR.PA.

Boeing referred all questions to Spirit.

Spirit Aero said its management expects to make a going-concern disclosure in its 2024 annual filing after a weeks' long strike shuttered most Boeing jet output.

The supplier which produces the fuselage for Boeing's strongest-selling 737 MAX jet, first warned in November there was "substantial doubt" about its ability to continue as a going concern, with the U.S. planemaker and Airbus coming to its aid.

In an investor presentation, Spirit Aero said it expects "operational improvement and higher delivery rates to drive better results in 2025," as Boeing plans to bring MAX production back to a rate of 38 a month.

Spirit's deliveries increased about 15% in the fourth quarter, led by higher Boeing 737 and Airbus A320 shipsets. A shipset refers to sets of structural fuselage components produced or delivered for one aircraft.

Reuters reported last week that Spirit Aero increased fuselage production to 31 a month, up from 21.

Spirit expects revenues of $1.66 billion in the quarter ended on Dec. 31, 2024, surpassing analysts' average estimates of $1.61 billion.

Spirit Aero expects to report a loss of $413 million, owing in part to high labor and raw material costs as the aerospace supply chain remains strained. It had posted a profit of $291 million a year ago.

Spirit Aero also said it is expecting forward losses due to Boeing's widebody 787 program, along with Airbus's A220 and A350.

(Reporting by Utkarsh Shetti in Bengaluru and Allison Lampert in Montreal; Editing by Vijay Kishore and Nick Zieminski)

((UtkarshUmesh.Shetti@thomsonreuters.com;))