After just 22 minutes in the air, Captain Tammie Jo Schults was faced with the fight of her life at 32,000 feet.

That fight was to survive and save every passenger on board her Dallas-bound Boeing 737 jet in April, 2018.

For Captain Schults and her first officer Darren Ellisor, their journey started smoothly, like every other flight she'd controlled from the cockpit.

But this day was different. In fact, she was never supposed to be in the driver's seat, but decided to swap shifts with her pilot husband Dean so she could make it to their son's school athletics competition in Texas.

READ MORE:
The Big Read: How the horror of Southwest Airlines flight unfolded
Southwest Airlines passenger tells why Jennifer Riordan couldn't be saved
Passenger next to Southwest Airlines flight victim Jennifer Riordan recalls horrific ordeal
Woman who died in horror Southwest flight named as mum of two

Cruising out of New York, like a crack of thunder, there was a loud bang from one side of the aircraft and suddenly, the Boeing plane rolled 41 degrees to the left.

Smoke began to fill the cabin and flight attendants rushed row by row to make sure all passengers could get oxygen from their masks that had dropped from the overhead.

As the pilots tried to remain calm and keep control of the 737, they became blinded as billowing black smoke filled the cockpit. Short of breath and sight Schults, a New Mexico native and mum-of-two, calmly called for assistance unaware of the horror unfolding in the cabin.

"We couldn't see, we couldn't breathe, and a piercing pain stabbed our ears, all while the aircraft snapped into a rapid roll and skidded hard to the left as the nose of the aircraft pitched over, initiating a dive toward the ground," Schults wrote in her new book, Nerves of Steel: How I Followed My Dreams, Earned My Wings, and Faced My Greatest Challenge, which launched this week.

Following 16 months of near-silence about the terrifying flight, Schults said in an interview with Elle to coincide with the book launch that she thought they had been "hit by another aircraft" when the plane began to plunge.

"The hit was so hard, and the jolt was so violent," she recalled.

"We heard the explosion. We could see the engine instruments blinking and winding down. Then there was this shudder. We couldn't focus our eyes on anything, and smoke spilled into the cockpit. The roar was so loud we couldn't hear our own voices. Darren and I were yelling to each other, but we used hand motions because it was so loud."

The plane's left engine had exploded mid-flight, sending shrapnel flying through the air and causing a passenger's window to smash.

As flight attendants rushed row by row to make sure all passengers could get oxygen from their masks that had dropped from the overhead, a devastating scene was unfolding in row 14.

When flight attendant Rachel Fernheimer arrived, she saw 43-year-old passenger Jennifer Riordan still restrained by her belt but with her head, torso and arm hanging out a window that had been broken open by the engine explosion.

After several failed attempts to reach the pilots by intercom because of the rush of air and noise, flight attendant Seanique Mallory was finally able to relay the situation to the cockpit who had already planned an emergency landing of the crippled Boeing 737-700 in Philadelphia.

In a message to air traffic control, Schults processed what was happening in the cabin and calmly called for assistance before explaining the dire situation that was unfolding inside the plane.

"I had this burst of adrenaline that made me think so fast and remain so calm," she said.

"I was thinking to myself, 'I don't think everything is going to stay on this aircraft for us to land, but I'll do everything in my power to make sure we land safely'.

"After we landed, I put away my oxygen mask, collected my stuff, made sure I got my headset and shook hands with the passengers as they exited. Then I texted [my husband] Dean a picture of the busted engine and said, "I flew this"."

The harrowing details from the April flight were released for the first time by the US National Transportation Safety Board in November last year, detailing how the engine failure on Southwest Flight 1380, which carried 144 passengers and five crew members, exploded.

Tragically, despite every effort, Jennifer Riordan wasn't able to be saved from her injuries, making the 43-year-old mother-of-two the only fatality from what could have been a far worse situation.

"The only regret I have is that when they brought Jennifer forward, instead of sitting back to let the medical team just do what they do, I wish I could have helped cover her a little better," Schults said of Riordan's death.

"I prayed there was still life in her, and I remember thinking, 'She has got to be freezing'. It bothered me that I didn't go get my sweater to put on her. It's small, but stepping in and extending a hand to help always makes a big difference."

Schults said in an interview prior to the book launch that she initially hadn't wanted to speak publicly out of respect for Riordan's family, but that the late woman's husband had been generous in his praise of the pilot and crew who tried to save her life.

"When you lose a passenger, it has a completely different posture than when you don't," she said.

"I was grateful that we made a successful landing and I was in a position to know, more than anyone, that that wasn't a guaranteed fact when everything happened, even until we touched down.

"When there's a loss of life, it isn't eclipsed by all the good that happens. Plus, there were so many heroes that day. I had flight attendants and passengers disregarding their own safety to help people.

"No one had any idea if we were going to make it but everyone was assisting each other with oxygen masks and seat buckles. A retired nurse, Peggy, got up and did CPR on a passenger, and then that passenger got down on their knees and tied the shoes of a stranger just because their arms were full. Heroes come in all forms."

Tammi Jo Schults' book, Nerves of Steel: How I Followed My Dreams, Earned My Wings, and Faced My Greatest Challenge, is available now.