Britain's competition regulator said on Monday it has started a Phase 1 investigation into Boeing's planned acquisition of Spirit Aerosystems, setting a deadline of August 28 for a decision.
The Competition and Markets Authority (CMA) had said last week that it was weighing a probe into whether the deal could affect competition in the country or in other markets.
Last year, Boeing agreed to buy back Spirit in a $4.7 billion all-stock deal to streamline its operations and improve quality control, years after spinning off the key supplier.
In April, Airbus finalized a deal to buy several of Spirit's facilities tied to its aircraft programs.