2nd bike-bus tragedy

An elderly bicyclist was struck and killed by a bus in Chelsea Saturday — the second fatal charter-bus collision in the neighborhood in a week.

Michael Mamoukakis, 80, was pedaling south on Seventh Avenue at about 1:35 p.m. when the bus began turning left onto West 29th Street and struck him at about 1:35 p.m., cops said.

“The bike, I guess, was in the crosswalk,” the driver, still visibly shaken hours after the crash, told The Post.

The driver said she heard a loud thud.

“Somebody was hollering that he hit the bus [and] for me to stop,” said the driver, who asked not to be identified by name.

“And I stopped. We went and checked, and he was trying to get up. Somebody got on top of him and was holding him down, [telling him], ‘Don’t move.’ ”

“He was trying to breathe,” said passer-by Mary Cunningham, 57. “Stay with me,” she said another passer-by urged.

On Monday, a Manhattan investment banker on a Citi Bike was fatally struck by a charter on West 26th Street.

It was the first death in the 4-year-old shared-bike program.