(CBS News)-- Airline mergers are nothing new in this economy, but the merger between United Airlines and Continental is causing some pilots concern. To operate as one airline, the two companies need to merge flight training, too -- and some pilots worry that having to learn new cockpit procedures is having an impact on safety in the skies. Pilots point to at least three reported instances when passengers may have been in danger when planes almost landed without their wheels down.
If you ask some cockpit crews today, you might not get the confidence in the pilots' training that you're looking for, CBS News national correspondent Lee Cowan reports.
"We're being tasked with learning that new procedure without having the opportunity to effectively practice it," Captain Rory Kay, of the United Airline Pilot's Association, told CBS News. "We're just sitting at home in our armchairs reading (a manual)."
The United pilots union is expressing worry after having to re-learn procedures to fly some of the world's busiest routes. It's all because United merged with Continental, and the new training practices for the brand new combined airline are making some pilots feel like they're back in flight school.
Captain Wendy Morse, of the United Airline Pilot's Association, said, "It has to be one set of procedures, so it's a lot of learning, a lot of retraining, and that retraining requires a very robust training program to make sure it becomes innate."
The United pilots union says it worries the new, merged airline is relying too much on Internet-based learning -- and not enough on time in flight simulators.
Capt. Chesley "Sully" Sullenberger, who is now retired and a CBS News aviation and safety expert, said there is no substitute for being in the simulator. He said, "Practicing these procedures time and time again (is essential) until it becomes part of your routine."
The airline union claims there have already been incidents in which pilots have become so distracted by the new techniques that they've made mistakes, forgetting to put the landing gear down, for one.
Kay told CBS News the procedures in his cockpit have "changed dramatically."
The airline denies the allegations, saying, "These claims are baseless and are an attempt ... to influence contract negotiations under a false guise of safety."
But Morse said of that statement, "Nothing could be further from the truth." She added, "We've had to take our attention from our contract negotiations, away from contract negotiations, and instead, focus them on safety."
With the clock ticking, the Federal Aviation Administration has given its blessing to make the two airlines one. So, for now, the training regimen remains.
"You have realize that there are many incentives to quickly merge two different airlines and to achieve the synergies and to realize the economic benefits of the merger," Sullenberger said. "And the sooner that's done, the better the bottom line."
Merging two airlines is complicated enough, but merging two training manuals, may prove even harder, Cowan remarked.
"Early Show" co-anchor Jeff Glor added on "The Early Show" that the next big step in the United-Continental merger is combining the two carriers' reservation systems. That's supposed to happen in the first quarter of 2012.