New York City ? When the twin towers came down on Sept. 11, 2001, deputy police inspector Robert Lukach was there, working on the pile, digging through the rubble for survivors.

Joe Downey, a New York City fire chief, was there too. He also was in Mississippi after Hurricane Katrina and in Haiti after Hurricane Gustav.

Now, the men are leading a team of 80 specialists on a search-and-rescue mission through the wrecked mass of concrete and metal in Haiti’s earthquake-ravaged capital, using technology that has been improved since the Sept. 11 attacks.

The squad touched down in Port-au-Prince on Saturday after a two-day wait for clearance to land at the destroyed city’s overloaded airport.

By early evening, 16 members of the team were working to rescue five people trapped on the bottom floor of a three-story grocery store that collapsed during the earthquake, police spokesman Paul J. Browne said.

They were trying to cut through concrete blocks to reach the survivors, who told rescuers they had been living on food and water in the store, Browne said.

Before leaving, Lukach said he was more optimistic about finding survivors in Haiti than he was at ground zero.

“That quickly became a recovery mission. But this is still a rescue mission, and we are hoping for the best,” he said.