"We're not the corps of veteran controllers that we were 4 or 5 years ago," offered RDU controller John Brown.
According to a government report, control tower managers, training officers, and union officials all say that the number of trainees working in a control tower should be limited to 20 to 25 percent.
Investigative reporter Steve Daniels asked Brown if the margin of safety is where he'd like to see it.
It's certainly not as compared to a couple of years ago," he responded.
Brown is a veteran air traffic controller at RDU. He's been working for the FAA for 22 years. Now, he's the union representative at the RDU tower.
"Is it a pressure cooker in there?" asked Daniels.
"It can be at times," Brown responded.
"You're dealing with the lives of thousands of people on any given day?" asked Daniels.
"Yes I am. It's very rewarding at the end of the day to know that you've done a good job and people have traveled and landed and taken off safely," said Brown.
But he's concerned because he says the RDU tower is turning into a classroom - now more than ever. He says there are 17 trainees and 29 fully certified controllers keeping an eye on the trainees.
That's higher than the national average and he says the trainees are prone to mistakes.
For the most part, the trainees we are seeing here have very limited background or experience, because they just haven't seen weather issues, equipment issues, so we're having to teach them as we go," said Brown.
"Are you stepping in and preventing problems on the job?" Daniels asked.
"Absolutely, instructors have override capability and they are plugged in with a trainee they can plug in and override any transmission and take over the position if they need to and quite often that happens," said Brown.
"Because they are trainees?" asked Daniels.
"Yes," Brown responded.
"They are learning on the job?" asked Daniels.
"They are and I'm a, I mean, they're gonna make mistakes," said Brown.
The controller's union points to three recent air safety incidents it says were caused by trainees. The NTSB says in Cleveland last month, the same trainee caused two different "runway incursions" two weeks apart. That means the trainee cleared two airplanes on to the same runway at the same time.
"Once is bad enough, but something that that important, planes possibly colliding - I mean, that's horrible," said Brown.
And in May, two airliners had a near mid-air collision in the sky over Kentucky. The controllers union says a trainee in Memphis was to blame.
"How often do you see a reduced margin of safety?" Daniels asked Brown.
"Just about on a daily basis," he responded.
"Where is the training plan falling short?" Daniels asked.
"The training plan is falling short because of the sheer number of trainees competing for training time," Brown said. "They are a very important part of the workforce here now. And for the most part, they are very intelligent and eager guys and girls that are doing a great job. We just aren't providing them with the optimum training in my opinion."
The situation is likely to continue. The FAA is trying to reach a goal of hiring and training 17,000 new controllers in the next 8 years.
The flight controllers union says it is negotiating with the FAA for a new contract right now, but said going public with its concerns is not related to those negotiations.
For its part, the FAA says only four of the trainees are in the early stages of their training.
"Every controller, whether fully certified, or partially certified, is held to the same high standard of performance that must be maintained to ensure that safety is never compromised," it said in a statement.
It also says training is a major responsibility of certified professional controllers at Raleigh-Durham.
"CPC's play a critical role in sharing their vast knowledge, experience and air traffic control expertise with new employees, just as previous generations of controllers trained them," said the FAA.
The FAA also says staffing at RDU exceeds targets and says five new trainees will arrive in October and another seven by the end of 2010.