PHILADELPHIA (REUTERS) - An engine on a Dallas-bound Southwest Airlines flight with 149 people aboard apparently exploded on Tuesday (April 17), forcing an emergency landing in Philadelphia as one passenger was killed after she was nearly sucked out a window of the plane, the airline and federal officials said.

The fatality on the flight from New York was the first in a US commercial aviation accident since 2009, according to National Transportation Safety Board (NTSB) statistics.

After an engine on the plane's left side blew, it threw off shrapnel, shattering a window and causing cabin depressurisation that nearly pulled out a female passenger, according to witness accounts and local news media reports.

"We have a part of the aircraft missing, so we're going to need to slow down a bit," the plane's captain, Tammy Jo Shults told air traffic controllers in audio released on NBC News.

Asked by a controller if the jet was on fire, Shults responds it was not but added: "They said there is a hole and someone went out."

"A woman was partially drawn out of the plane and pulled back in by other passengers," Todd Bauer, whose daughter was on the flight, told NBC's affiliate in Philadelphia.

NTSB Chairman Robert Sumwalt told a news briefing in Washington that one person had been killed, but declined to elaborate. The fatality was later identified as 43-year-old Jennifer Riordan by the Associated Press.

She was a vice-president of community relations for Wells Fargo & Co in Albuquerque, New Mexico, and leaves behind a husband and two children.

NO FIRE

"The entire Southwest Airlines Family is devastated and extends its deepest, heartfelt sympathy to the customers, employees, family members and loved ones affected by this tragic event," Southwest said in a statement.

Flight 1380 had 144 passengers and five crew members, Sumwalt said. The flight data recorder showed the plane was at 32,500 feet when the engine failed about 20 minutes into the flight, according to CNN.

One passenger was taken to the hospital in critical condition, and seven other people were treated for minor injuries at the scene, said Philadelphia Fire Department spokeswoman Kathy Matheson. Matheson could not confirm how the passenger in critical condition sustained her injuries.

Sumwalt said the NTSB believes parts came off of the engine but it has not determined if it was an "uncontained engine failure."

"There are protection rings around the engine to keep shrapnel from coming out. Even though we believe that there were parts coming out of this engine, it may not have been in that section of the engine that technically would qualify this as an uncontained engine failure," he said.

"We don't think there was a fire at all," he told the media briefing before departing for Philadelphia.

He said the NTSB sees about three or four uncontained engine failures a year, including non-US carriers.

'EVERYBODY WAS GOING CRAZY'

Flight 1380 was diverted to Philadelphia after crew members reported damage to an engine, the fuselage and at least one window, the Federal Aviation Administration said.

"Everybody was going crazy, and yelling and screaming," passenger Marty Martinez told CNN.

Martinez said objects flew out of the hole where the window had exploded, and "passengers right next to her were holding onto (the woman being pulled out). And, meanwhile, there was blood all over this man's hands. He was tending to her."

Television images showed that most of the outer casing around the left engine of the Boeing Co 737-700 had ripped away and a window near the engine on the plane's left side was missing.

Southwest said the aircraft had been bound for Dallas Love Field in Texas from New York's LaGuardia Airport before it diverted to Philadelphia.

"All of a sudden, we heard this loud bang, rattling, it felt like one of the engines went out. The oxygen masks dropped," a passenger, Kristopher Johnson, told CNN. "It just shredded the left-side engine completely. ... It was scary."

Southwest shares fell more than 3 percent after the NTSB reported the fatality, then cut losses to close down 1.1 percent at $54.27 a share on the New York Stock Exchange.

Boeing said on Twitter that it was aware of the incident and was "gathering more information."

The plane's engines are made by CFM International, a French-US venture co-owned by Safran and General Electric, which was not immediately available for comment.

Southwest Airlines said the aircraft was inspected on Sunday and the airline had not been aware of any previous issues with the jet or its engine.

Southwest Chief Executive Gary Kelly said on a call with the media that Tuesday's fatality was the first of its kind in the airline's 51-year history. Mr Kelly said he had reached out to the family of the victim, though he had not yet managed to make contact.