UPDATE 1-Spirit AeroSystems profit beats on higher shipments

(Adds 2018 forecast, background)

Feb 2 (Reuters) - Aircraft parts maker Spirit AeroSystems Holdings Inc reported better-than-expected quarterly results, helped by higher deliveries to Boeing Co and Airbus SE, its biggest customers.

Spirit Aero forecast 2018 earnings in the range of $6.25 to $6.50 per share, topping Wall Street estimate of $5.85.

The company also predicted revenue of $7.1 billion to $7.2 billion, compared with analysts' expectation of $7.13 billion, according to Thomson Reuters I/B/E/S.

The Wichita, Kansas-based company said it expects 2018 free cash flow of $550 million to $600 million, while Wall Street was anticipating $572.85 million.

Spirit Aero, which increased its share repurchase authorization up to $1 billion, earned $1.32 per share on an adjusted basis in the fourth quarter ended Dec. 31, beating the average estimate of $1.21. nCNWVTPBVa 3/8

Total revenue rose 9.2 percent to $1.71 billion and was above the $1.66 billion expected by analysts. (Reporting by Ankit Ajmera in Bengaluru; Editing by Maju Samuel)