BERLIN (AP) — The European Aviation Safety Agency is grounding Airbus helicopters similar to one that crashed in April near the Norwegian city of Bergen, killing 13 people.

The Cologne, Germany-based agency said Thursday that the "precautionary measure" applies to Airbus Helicopters EC 225 LP and AS 332 L2 models.

The exact cause of the April 29 accident hasn't been established, but preliminary findings by Norway's Accident Investigation Board indicate that it could have been caused by a faulty gear box. The main rotor came loose from the aircraft just before it crashed.

Airbus Helicopters said on its website that it "supports EASA's cautious approach."