CHICAGO (CBS) — Friday marks the anniversary of the deadliest commercial aircraft accident in the U.S. – the crash of American Airlines Flight 191 near O’Hare International Airport.

As WBBM Newsradio’s Steve Grzanich reports, 33 years later, air safety has improved dramatically, according to CBS News Aviation analyst and former National Transportation Safety Board Chairman Mark Rosenker.

LISTEN: WBBM Newsradio’s Steve Grzanich reports

“We are really looking at the equipment, the training, the oversight, the regulatory activity—all of those things coming together to produce one of the safest periods of aviation in the entire time of commercial aviation,” Rosenker said.

On May 25, 1979, 271 people died when the McDonnell Douglas DC 10 lost control and crashed.

During takeoff, the left engine and pylon assembly and about 3 feet of the left wing separated from the plane and came crashing down to the runway.

The plane kept rolling to the left until it was flying sideways and the wings were vertically oriented, and the nose was pointed toward the ground, according to the official accident report.

Improper maintenance led to the loss of the engine.

The plane crashed into an open field off Touhy Avenue in Elk Grove Township, and wr

“This was a tragic accident that really never needed to happen. This came as the result of a maintenance flaw where shortcuts were being taken by the maintenance crews,” Rosenker said.

He offered this to air travelers this Memorial Day weekend.

“In the equipment aspect of it, in the talent that is flying these airplanes, the air traffic controllers that are controlling those aircraft in the air – all of those come together to make it an extremely safe form of transportation,” Rosenker said.

“The most dangerous aspect of your flight will be the drive to the airport,” he said.