An investigation continues into the cause of a Sikorsky S-76A++ operated by Era Helicopters that crashed within 30min of take-off on a maintenance check flight.
The wreckage of the crash that killed all three crew revealed two tail rotor blades were missing, says the National Transportation Safety Board (NTSB). The rotor blades have not been found and possibly separated from the aircraft during the flight.
The helicopter crashed about 8km (4.3nm) from the threshold of runway 33 at Lake Charles Regional airport, Louisiana.
The crew was returning to the airport and cruising at 1,000ft (305m) when the pilot declared an emergency to the airport control tower, states the NTSB. The pilot said he would be "immediately landing off the airport".
The S-76A++ - serial number 760369 - was manufactured in 1990.