Federal regulators said Thursday they are investigating a near-collision of a US Airways jet and a small cargo plane that came within 50 to 100 feet of each other over Minneapolis just after takeoff. Air control radio traffic showed the cargo pilot failed to turn as directed.

The pilots of the two planes never saw each other as they passed in cloud cover at about 1,500 feet on Sept. 16, although the US Airways captain said he heard the cargo plane go by, the National Transportation Safety Board said. No one was injured and there was no damage.

US Airways Flight 1848, an Airbus 320, took off from Minneapolis-St. Paul International Airport for Philadelphia with 90 passengers and five crew members shortly before 7 a.m. on Sept. 16. A twin-engine Beech 99 turboprop operated by Bemidji Aviation Services took off on a parallel runway on the left at about the same time.

The NTSB said the tower then instructed the US Airways crew to turn left, which caused it to cross paths about a half-mile past the end of the runway with the cargo plane, which had only the pilot aboard and was bound for La Crosse, Wis. A collision might have dropped wreckage on residential areas and busy freeways.

"We heard the guy go by," the US Airways captain radioed back to air traffic controllers, according to radio traffic archived by LiveATC.net, a website that streams such traffic from airports around the world.

The transcript shows that a controller told the cargo plane before takeoff that he should turn due south after takeoff. Two minutes later, the controller asks the pilot if he was in his turn. The pilot asked for a repeat. Portions of what followed were garbled, but then the controller asked:

"OK, um, why didn't you start the turn once you were airborne?"

"Well, (garbled) ... sorry about that," the cargo pilot replied.

On another frequency with a different controller, the pilot of the US Airways jet asks, "What's this guy doing on our left side?"

The controller replied it appeared that the Beech 99 had climbed straight out from the runway instead of turning.

A few minutes later the controller said he would have the tower supervisor call the US Airways pilot and tell him what happened, according to the transcript provided by LiveATC.net.

The jetliner had an automated system that instructed the pilots to climb to avoid a crash, and they did. The cargo plane didn't have the system, and its pilot was unaware the Airbus was nearby, the NTSB said.

Published noise reduction procedures for the two runways recommend that controllers order planes to turn to different headings after they take off when possible to spread out the impact on the neighborhoods below.

A rise in near-collisions nationwide prompted the Federal Aviation Administration this summer to launch an effort to learn why dangerous errors were being made by air traffic controllers and pilots. The FAA also said it had seen a spike in incidents where planes were violating minimum separation distances.

"Human error seems to be rearing its ugly head a lot lately," said Joseph Schwieterman, a transportation expert and economics professor at DePaul University in Chicago.

Generally, planes must keep a lateral distance of about 6 miles at high altitudes and nearly 3.5 miles when approaching airports. Planes can be closer during landings.

FAA spokeswoman Elizabeth Isham Cory said this incident fell into "Category A," the most serious class of "operational errors" involving separation distance violations, because of the high danger of collision.

There were 10 operational errors at the Minneapolis airport in 2009 and this was the fourth this year, Cory said. But this was the only Category A incident among the 14, while the others were in lesser categories with little risk of a crash, she said.

"This is something we're very concerned about," Cory said. "We want to find out what happened and why. And we want to find out what we can do to prevent it from happening again."

Schwieterman said the automated warning system on the Airbus likely averted a disaster, supporting advocates who want the crash avoidance technology in all planes.

"Technology might have saved us from a cataclysmic outcome," Schwieterman said.

US Airways issued a short statement saying the airline's information is that its crew was complying with air traffic controllers' instructions when it happened.

The director of operations at Bemidji Aviation Services, Tracie Walters, declined to make its pilot available for an interview.

"We are cooperating with the investigation and besides that we have no comment," she said.

Some travelers at the airport Thursday said they were concerned about the near-miss but would keep flying.

"That's actually really scary, it really is," said Vickie Jensen, of Stillwater, who had just flown home from a business trip to Houston. "That does make me a little leery."

Jason Johnson, of Minneapolis, his wife and their two young children were about to leave on a family trip to Phoenix when they heard about the near-miss.

"Whenever these things come out you always hear that they're going to take steps, but I never hear actual action plans," Johnson said. "It's more, 'We will do something,' but you never hear what they actually do."

___

Associated Press writer Jeff Baenen contributed to this report.