FAA administrator unclear whether airliner close calls are on the rise

  (CNN) -- After at least six incidents this year, the nation's top aviation official says he does not know whether close calls involving airliners are on the rise, but says the issue and its causes will be examined at a safety conference next week.

"It's a good question," Billy Nolen, acting head of the Federal Aviation Administration, said after testifying to the Senate Commerce Committee -- his second time there in a month.

Nolen defended his agency's handling of the safety incidents, some of which were averted when pilots -- not the air traffic controllers from his agency -- avoided a collision. He said officials are "treating each of these as if it had been an actual event."

"The FAA absolutely has a grasp on the situation and it's something that we look at every day," Nolen told reporters. "We'll take a look at these near misses and see if there are lessons to be learned."

He said a major safety meeting next week will include industry officials and ask the "hard questions."

"Let's just stop to see -- are there any dots that we need to connect, and if so what might they be?" Nolen said.