Updated April 19, 2018 12:05:26

Photo: Family, friends and community leaders are mourning the death of Jennifer Riordan. (AP: Marla Brose/The Albuquerque Journal)

A mother of two who was sucked out through a broken window on a commercial US airliner died from blunt force trauma to her head, neck and torso.

Bank executive Jennifer Riordan, 43, was wearing a seatbelt when the window she was sitting next to was broken by debris from an exploded engine, pulling her partially out of the plane.

Several passengers were injured attempting to drag her back inside the aircraft.

A spokesman for the Philadelphia Department of Public Health said Ms Riordan's death was ruled accidental.

Photo: The window was broken when the engine came apart. (Facebook: Marty Martinez)

The investigation into the deadly engine failure on the Southwest jet is focusing on whether wear and tear led to the catastrophic chain of events.

From investigators' initial findings, the accident appeared remarkably similar to a failure on another Southwest plane two years ago — an event that led the engine manufacturer and regulators to push for ultrasonic inspections of fan blades on engines like the one that blew apart at 10,000 metres over Pennsylvania on Tuesday.

When investigators from the National Transportation Safety Board examined the broken engine in Philadelphia just hours after it made an emergency landing, they immediately saw that one of the left engine's 24 fan blades was missing.

"This fan blade was broken right at the hub, and our preliminary examination of this was there is evidence of metal fatigue where the blade separated," said NTSB chairman Robert Sumwalt.

Photo: National Transportation Safety Board investigators examine damage to the Southwest Airlines engine. (AP: NTSB)

Metal fatigue is a weakening of metal from repeated use and involves microscopic cracks.

It can occur in fan blades, the aluminium skin on most planes or other metal parts.

Investigators will focus on whether the fan blade broke off at cruising speed — about 800 kilometres per hour — and started an "uncontained" engine failure that sent debris flying like shrapnel into the plane, where it broke a window.

As a precaution, Southwest said it would inspect similar engines in its fleet over the next 30 days.

The incident broke a run of eight years without a fatal accident involving a US airliner.

Jennifer Riordan remembered as selfless, gracious

The heroic pilot who calmly landed a Southwest Airlines flight after a mid-air explosion is a former US Navy pilot who was once denied an aviation career on account of being a woman.

Ms Riordan was remembered as a dedicated mother of two known for volunteering and who helped others find jobs.

"Jennifer's vibrancy, passion, and love infused our community and reached across our country," her family said.

"Her impact on everything and everyone she touched can never be fully measured. But foremost, she is the bedrock of our family."

She was well known in Albuquerque, New Mexico, where she built a career over more than two decades in community relations and communications after graduating from the University of New Mexico.

Her death generated an outpouring of grief and public sympathy from business leaders in Albuquerque, state elected officials, writers and activists — all who portrayed Ms Riordan as gracious and selfless.

The Greater Albuquerque Chamber of Commerce held a moment of silence on Tuesday night during a special reception for new University of New Mexico president Garnett Stokes.

Rebecca Avitia, the executive director of the National Hispanic Cultural Centre in Albuquerque, said that losing Ms Riordan casts a dark, heavy emptiness on the city.

"I've heard of references in Mesoamerican lore to a female spirit who appeared to people in need like a blazing sun with wings. In Albuquerque, that was Jennifer Riordan," Ms Avitia wrote in online post.

"Jennifer, I already miss you."

'We thought this might be it'

Photo: The actions of pilot Tammie Jo Shults were praised by passengers. (Twitter: Kristopher Johnson)

The pilots of the twin-engine Boeing 737 bound from New York to Dallas with 149 people aboard made an abrupt turn toward Philadelphia and began a rapid descent after the engine blew.

Oxygen masks dropped from the ceiling, and passengers prayed and braced for impact.

"We heard a loud noise and the plane started shaking like nothing I've ever experienced before," retired nurse Peggy Phillips told WFAA-TV in Dallas.

"It sounded like the plane was coming apart, and I think we pretty quickly figured out that something happened with the engine."

She said they started losing altitude and the masks came down, and "basically I think all of us thought this might be it".

Passengers praised one of the pilots, Tammie Jo Shults, for her cool-headed handling of the emergency.

AP

Topics: air-and-space, accidents, disasters-and-accidents, united-states

First posted April 19, 2018 06:25:52