By Foo Yun Chee and Theodora Arvanitidou

BRUSSELS (Reuters) - EU antitrust regulators are asking rivals and customers whether Safran's bid for Collins' flight controls business would give the French engine and aircraft equipment maker more market power, a person with direct knowledge of the matter said on Wednesday.

The European Commission, which is now examining the deal, has sent questionnaires, giving respondents until Feb. 24 to reply, the person said.

Safran announced the $1.8 billion deal to buy Collins Aerospace's actuation and flight controls business in July last year to position it for the next generation of aircraft. The deal is its biggest since it acquired seat maker Zodiac in 2018.

Actuators, which convert electronic instructions from the cockpit to the physical movement of parts to help control aircraft, provide critical cockpit functions such as providing extra lift during landing.

The EU competition enforcer is looking at conglomerate effects, the person said, referring to the impact of deals between companies in different industries or involved in unrelated business activities.

The questionnaire also asked about Safran's Horizontal Stabilizer Trim Actuation (HSTA) systems for aircraft stabilization and Collins' thrust reverser actuation systems (TRAS), among others.

Safran agreed to sell its electromechanical actuation business in North America, which includes its intellectual property, operations assets, talent, and long-term customer agreements for HSTA systems, to U.S. aircraft parts maker Woodward in December.

Safran said the divestment was a step forward towards the Collins deal. The Commission is scheduled to finish its preliminary review by March 21. It can open a four-month long investigation if it has serious concerns.

The UK's Competition and Markets Authority is also assessing the deal. Collins Aerospace is part of U.S. aerospace and defence giant Raytheon Technologies, recently renamed RTX.

(Reporting by Foo Yun Chee; Editing by Kirsten Donovan)