Why did a Delta plane crash in Toronto, and how did everyone ...

Mr Ronan highlighted the importance of the plane's high-impact 16g seats, which he said were "designed to absorb a great deal of punishment".

The seats can withstand deceleration of 16 times the force of gravity, and must pass rigorous testing using human dummies to model crash dynamics.

The seat legs, attached to a track on the floor, must be able to pitch down 10 degrees on one side and roll 10 degrees on the other side so that they do not break, said Kevin Campbell, founder of Aviation Consulting & Engineering Solutions, who is FAA-authorised to approve seats that are required to comply with the regulations.

In previous accidents, the FAA had seen seats piled up in the fronts of aircrafts, with bodies still attached in many cases, Mr Campbell said.

Mr Ronan said the regulations keep "the seat in place and bolted to the floor, so you have a higher degree of survivability in your seat itself and you have less likelihood that the seat is going to become detached, where you're now strapped into a moving object that's being bounced around the cabin."

The regulations also require a passenger to be able to withstand hitting their head and legs on the seat in front of them, and seats help absorb weight in their spine so that they do not break their back. Seatbelts are also less stretchy than they used to be so the restraint is more secure.

"As a result of that aircrafts are much, much safer," Mr Campbell said, and those factors were "absolutely" at play in improving safety in this crash.

"It really is remarkable that the seats did exactly what they were supposed to do, they stayed intact... the seatbelts worked just as they were supposed to, and the seats did not become detached from the floor," Mr Ronan said.

"Think of how many head injuries we would have had, spinal injuries we would have had, if the seat became detached."