Helicopter Accident Digest

24 February 2010                     FAA

AD 2010-05-51

Emergency Airworthiness Directive Concerning Eurocopter EC120B Helicopters

AD emulates action taken by EASA after a Eurocopter conducted an emergency landing due to excessive vibrations from the main rotor. Subsequent investigation found that the rotor hub had failed in one of three drag damper fittings.

Action requires sanding the area through the finish paint to the primer and inspecting for a crack. If a crack is found, the hub must be replaced with a new rotor hub “before further flight.”

The inspection must be done within 15 flight hours. Instructions are explicit:

“If you find scoring, paint flaking, or left-over identification plate adhesive, sand the area using No. 600-grit (fine grit) abrasive paper until the primer coat becomes visible and inspect the rotor hub for a crack.”