WASHINGTON — The first major US plane crash in a dozen years began to unfold in utterly undramatic fashion just before noon on Saturday when a big white passenger jet with red, blue, and yellow flashings banked to the right and began to descend toward the wide runways of San Francisco International Airport.
Inside the plane, seat backs were in the upright position, tray tables were locked in place, and the laptops, books, and toys that had entertained for more than 10 hours and 5,651 miles were stowed away for landing.
Outside, the skies were clear of the fog that so often shrouds San Francisco Bay, and the wind was light. Asiana Flight 214 was expected to reach the gate within minutes.
Benjamin Levy, who said he flies into the airport often, wondered about the approach when he saw that piers jutting out into the bay were much closer than he thought they ought to be.
A pilot who sat on the runway awaiting the OK to take off thought the Boeing 777 was tilted up at too high an angle for an approach.
And then in a searing scrape of metal against stone, the plane’s tail struck the sea wall that separates the edge of the runway from the bay. Within a minute or two, it was in flames.
Police officers responding to the crash, which killed two people and injured more than 180, threw knives up to crew members inside the jet so they could cut away the seat belts of some passengers. People jumped down emergency slides to escape the smoke. One walked through a hole where a rear bathroom had been.
The impact and the sight of smoke and flames sweeping through the Boeing 777’s fuselage left many wondering how nearly all 307 people aboard were able to make it out alive.
Inside the plane, passenger Vedpa Singh, who was sitting in the middle of the aircraft with his family, said there was no forewarning before the plane touched down hard and he heard a loud sound.
‘‘We knew something was horribly wrong,’’ said Singh.
The cabin filled with the screams of passengers and the roar of the plane sliding on its belly.
Jang Hyung Lee, 32, said he felt one bump and then a second, more violent smash. He wrapped his arms around his 16-month-old son as smoke began to fill the plane.
Before those flames broke out, there were just seconds for the passengers to flee. First they had to negotiate luggage that had tumbled from overhead bins and blocked the path to escape.
Levy, who was seated just behind one wing on the plane’s right side, pushed luggage aside and made his way toward an emergency door.
As the plane traveled those final miles toward Runway 28-Left, there was no indication from the cockpit that anything was amiss. But soon many on the plane and on the ground thought something was wrong with the plane’s approach.
Passengers expecting the comforting thud of wheels touching down instead heard the engines respond to a throttle pushed hard.
“The back got the worst of it,’’ passenger Elliot Stone said. “It opened up. . . . Then we fishtailed for another 300 yards.’’
The initial cabin smoke was minimal but soon fire ravaged the plane from the cockpit area to behind the wings, leaving a sooty gash in the aircraft’s roof.
But before the flames broke out, Levy reached an emergency exit and pulled the lever. The slide he expected did not deploy from the door — although at least two did from other doorways — so he helped people step down.
“We got pretty much everyone in the back section of the plane out,’’ he said. “I’m so thankful so many people go out of the plane quickly.’’