A child tucked into the same seat belt with an adult would be crushed by the g-forces of a violent landing or turbulence.

“I’d done this in a classroom, and it sounds great,’’ she said. “But I couldn’t believe I was putting people into their worst-possible nightmare.”

Tsao, like the three other parents of lap children on the flight, was reluctant but complied.

Brown was knocked unconscious briefly in the crash and suffered second- and third-degree burns. She eventually made her way out of the wreckage and met a distraught Tsao heading back inside to find her son. She blamed Brown for losing Evan. Brown recalled the encounter: “You told me to put my son on the floor. I did and now he’s gone,” Tsao said.

Brown replied, “That was the best thing to do. That was all we had.’’

But it was a turning point for Brown. She said the memory of Evan inspires and motivates her.

“Had he been in a child seat he probably would have survived, like everyone around him, and he’d been 26 (years old) now and 27 in September,’’ she said.