NEW YORK (CBSNewYork) — Many New Yorkers thought the worst when they heard an aircraft crashed into a building, so who’s protecting our skies in case next time it’s not an accident?

Onlookers take pictures on 7th Avenue after a helicopter crash-landed on top of a building in midtown Manhattan in New York on June 10, 2019. (Photo by JOHANNES EISELE/AFP/Getty Images)

It initially seemed like a terrifying case of déjà vu, but New Yorkers breathed a huge sigh of relief when authorities quickly said that Monday’s helicopter crash was not terrorism.

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But what if it was? How easy is it to fly into New York City airspace?

CBS2’s Andrea Grymes spoke to former FBI agent and security expert Manny Gomez.

“Unfortunately, this is the present danger that we live in,” he said.

The NYPD aviation unit is considered the first line of defense in the enforcement of no fly zones or restricted air space like near Trump Tower.

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Police pilots were grounded Monday because of the weather.

The unit declined an interview, citing the NTSB investigation now underway.

But police sources say when specific flight corridors are violated and a pilot doesn’t respond to radio communications, NYPD aviation can be dispatched to monitor, communicate or otherwise intercept an aircraft before the military.

“The NYPD has the ability to shoot a plane down if necessary,” Gomez said. “Obviously, we don’t want to shoot an aircraft out of the sky because then you have no control as to where that aircraft lands and it could land on top of a populated area and hurt a lot of people.”

Not every pilot is required to file a flight plan with the FAA. It depends on different factors, like the weather or what altitude they’ll be flying.

The building where a helicopter crash-landed on top is seen in midtown Manhattan in New York on June 10, 2019. (Photo by JOHANNES EISELE/AFP/Getty Images)

Mayor Bill de Blasio, speaking Monday night on CNN, said helicopters should not be flying over populated areas.

“I think the FAA needs to look at this very carefully and ask the question that they need to toughen up the rules or put more security or monitoring of the situation to make sure something like this couldn’t happen again,” he said.

Helicopter pilot Pete Zanlunghi, with Air Metro Helicopters, counters most who fly around New York City are responsible pilots.

“I think we’re restricted as far as we can go with aircraft in the New York area,” he said.

The FAA says it would be premature to consider any actions it may take pending the outcome of the NTSB investigation.

Congresswoman Carolyn Maloney is also renewing calls to ban unnecessary helicopters over New York City.