Even in a place accustomed to the murmur of terror alerts, a city that has accepted its subways and skyscrapers as targets, where you can almost block out roaring jets and blaring sirens these days, the news sent adrenaline racing.

For harrowing minutes at mid-afternoon yesterday, before the exact location and scope of what happened became clear, people turned to televisions or read text messages from friends and knew only this: A plane crashed into a building.

And then came an emotion, hard to define and distinct to the five years since the 2001 attacks on September 11 and probably more common here than anywhere else. You could call it relief, except relief is not usually laced with guilt. It was a small plane or helicopter, nothing bigger. The most intense fire appeared on television to be visible through two windows, just two, in an Upper East Side high-rise. And later in the day, word that two people had been killed. Just two.

Still, even after authorities ruled out terrorism and the crash emerged as, in the words of a Homeland Security Department spokesman, a “terrible accident,” it was impossible not to think of September 11. It was on the mind of Beata Jankowska, who works as a housekeeper on the 33rd floor of the very building that was hit, on East 72nd Street close to the East River in Manhattan.

“Everything reminds me of Sept. 11,” Ms. Jankowska said. She was preparing a dinner of chicken marsala when she heard an explosion, saw flames below her out the window, and then raced down 33 flights of stairs to get out, taking nothing with her.

“I was very afraid,” she said. “I remember September 11. I was watching that from the very first second.”

You could look at a television and wonder whether what you were seeing was live or five years old: Gear-burdened firefighters trudging toward the scene. Crowds of people in a densely populated neighborhood, all looking up. Public officials were quick to say there was no indication an attack had taken place, but they acknowledged the crash — on another 11th — had rattled the city’s psyche.

“I understand that since September 11, when something like this happens, there’s a high level of anxiety, and people reflect back to September 11,” Governor Pataki said on CNN.

And even after it was clear the crash was an accident, “still you’re thinking it could be something else, and you don’t feel comfortable taking the subways,” Catherine Schreckinger said. Ms. Schreckinger was running errands on 57th Street when her 13-year-old daughter called from school to say administrators were not letting the children leave because of the crash.

“People in New York are traumatized still. People are thinking of it always, every day. I think, ‘What if? Who will be the person I’ll share this horrible experience with?’ People from other countries don’t understand that. It wasn’t one day. It was months and years,” she said.