The European Union's competition regulator says it has opened an in-depth probe of United Technology's $16.4 billion acquisition of aerospace supplier Goodrich.

The European Commission said its initial analysis of the deal "indicated potential competition concerns regarding the markets for engine controls and AC power generators," where both companies already have big market shares.

It said it is also worried that the deal will remove Goodrich as an independent supplier of fuel nozzles and engine controls.

The EU's Competition Commissioner Joaquin Almunia warned that "the aviation equipment industry is already concentrated and is characterized by high barriers to entry."

The Commission now has until Aug. 9 to decide whether to approve or block the deal.