WASHINGTON (Reuters) - The U.S. National Transportation Safety Board opened an investigative hearing on Wednesday into the fatal engine explosion on a Southwest Airlines LUV.N Boeing 737 that killed one passenger.

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Dallas-based Southwest has been under scrutiny since an engine on a flight headed from New York to Dallas blew apart in mid-air over Pennsylvania, shattering a plane window, flinging shrapnel and killing passenger Jennifer Riordan, one of 149 people aboard.

The episode, which has raised concerns about the safety of similar engines, was the first fatality on a U.S. commercial passenger airline since 2009.

The hearing in Washington turned to a detailed summary of the engine failure on flight 1380, including details of the fan blade design and development history of the engine type that failed, a CFM56-7B made by CFM International, a transatlantic joint-venture between General Electric Co GE.N and France's Safran SA SAF.PA.

The hearing also focused on engine fan blade inspection methods.

A CFM representative told the NTSB panel that coating condition, lubrication and the length of operating time contributed to the fan blade separation.

The NTSB also released factual findings that disclosed the flight crew had difficulty reaching flight attendants after the engine failed and did not immediately learn that a passenger had been injured.

The engine on the plane’s left side spewed shrapnel when it blew apart, shattering a window and causing rapid cabin depressurization that nearly pulled a female passenger through the hole, the NTSB said.

The NTSB report said two passengers were eventually able to pull the woman, who was still in her seat belt, back inside the plane.

Representatives from Chicago-based planemaker Boeing BA.N, and Southwest Airlines were also at the hearing.

“We all have the same goals,” Southwest said in a statement, “to share facts, learn what happened, and ensure this type of event never happens again.”

Boeing spokesman Paul Bergman said safety was the planemaker’s top priority and it will continue to support the NTSB and provide technical assistance.

A CFM spokeswoman declined comment while the hearing was in process.

The hearing comes as Indonesian authorities investigate last month’s deadly Lion Air crash involving a newer version of Boeing’s best-selling single-aisle aircraft, the 737 MAX.