​After a mid-air collision between a small charter plane and a sightseeing helicopter over the Hudson River this summer killed nine people, observers were quick to blame the Federal Aviation Administration for poorly regulating the airspace, letting it become clogged with private planes. Today the F.A.A. announced a host of changes in the way planes can maneuver in the flight zone.

As of Thursday, the airspace over the Hudson -- which stretches to about 20 miles northeast of the Statue of Liberty and is less than three quarters of a mile wide -- will be split into two zones: a low-altitude zone for local traffic, and a higher one for long-distance flights...

Local planes and helicopters will be restricted to an altitude of 1,000 feet or less. Those passing through the New York City area on longer flights to other destinations will operate between 1,000 feet and 1,300 feet. Speeds in both zones will be restricted to about 160 mph (though this doesn't appear to have been an issue in the August crash). In addition, southbound aircraft will travel along the Jersey side of the river, while northbound traffic will use the New York side. In the past, pilots were free to choose their own routes.

The collision this summer was the city's worst air disaster in eight years. Three people died on the single-engine charter plane, which was traveling from Teterboro Airport in New Jersey and was rising to a higher altitude when the crash occurred. Five Italian tourists who were on a helicopter sightseeing tour also died.

Both an air traffic controller and a supervisor were on duty at Teterboro Airport in New Jersey the morning of the crash. Both men have been fired after an investigation found they weren't monitoring the pilot of the small plane as closely as they should have. The air traffic controller did not alert the pilot of the small plane that a helicopter was moving in the airspace above it. The controller also failed to notice that the pilot of the small plane -- who had radioed for assistance after indicating that he was unfamiliar with the area -- read back the wrong radio frequency after being told to switch to the control tower at nearby Newark Liberty International Airport. The supervisor was out of the building on a personal errand.

But F.A.A. regulations do not require air traffic controllers to monitor small planes and helicopters continuously, as they do with commercial flights. And the new rules, which go into effect on Thursday, do nothing to change that. Image (cc) flyinace2000.