Passengers on a jet which crashed in San Francisco were told by the pilot to stay in their seats after the aircraft came to rest on the runway.
It was not until a fire erupted 90 seconds after the crash that the order to evacuate the Asiana airlines Boeing 777 was given, according to the National Transport Safety Board on Wednesday.
The Asiana flight crashed Saturday when its landing gear and then its tail clipped a rocky seawall just short of the runway.
Deborah Hersman, the chairwoman of the NTSB, said the pilot told passengers to stay in their seats while he contacted the control tower at the airport.
She added that, "in order to get certified, an aircraft manufacturer has to show that a fully loaded aircraft can be evacuated, fully evacuated within 90 seconds."
"What we saw here was that the first doors and slides weren't opened for about 90 seconds."
Then a fire erupted outside the plane, and the doors were opened and escape slides were inflated. Two flight attendants were pinned by slides that inflated inside during the impact.
The crash killed two of the 307 people on board and injured scores of others, among them three flight attendants from the tail section who were thrown onto the runway. Nearly 20 people remained in hospital on Wednesday.
A third person, a Chinese girl, died in hospital on Friday morning, doctors and Chinese officials confirmed.
The child had been in critical condition, according to a statement from two doctors at San Francisco General Hospital.
Investigators have said the plane came in far too low and slow. The pilot was still training on the 777 model, and while his co-pilot was experienced it was his first time instructing someone else on the plane.
Former NTSB Chairman James Hall said the agency was "definitely going to focus on what type of policy Asiana had in terms of crew pairing".
"That's what the airline needs to do, be responsible so that in the cockpit you're matching the best people, especially when you're introducing someone to a new aircraft."