Retirements of veteran air traffic controllers have surged beyond government expectations since the Bush administration imposed a contract on their union on Labor Day last year, new data shows.

While air travelers experience record delays, the Federal Aviation Administration regularly proclaims all is well with its work force.

But the National Air Traffic Controllers Association equally often warns that controllers are overworked in major centers it considers undermanned and could pose a safety risk.

One thing is certain: A veteran force of controllers — most hired in the early 1980s after President Reagan fired 11,000 members of a predecessor controllers union — is being replaced by lower-paid, less experienced young controllers. That long-expected transformation is occurring faster than the government anticipated.

The Associated Press learned that the FAA recently considered offering a cash bonus of 25 percent of one year's pay to top-rated veteran controllers who delay retirement two years. FAA spokeswoman Laura Brown denied that the proposal, drafted in August and since rejected, was spawned by any difficulty staffing control centers.

"It didn't fit our needs right now because hiring is going so well," she said. "In the future, some retention proposal could come up again."

The controllers, on the other hand, "believe the situation is quickly spinning out of control," union president Patrick Forrey told a news conference Monday. "New controllers need years of seasoning to move traffic as quickly as veteran controllers," he said, adding that the way to retain veterans would be to pass a House bill that would force the FAA to reopen negotiations on a contract. The administration opposes that step.

Later, acting Federal Aviation Administrator Bobby Sturgell told a separate news conference that "the system is staffed and staffed well." He acknowledged that "a couple facilities" were moving slower with on-the-job training of new hirees than the agency wanted, but added "all the safety data shows the system is safe."

A total of 828 controllers retired in the 12 months that ended Sept. 30, the FAA said late Friday. That's 28.8 percent more than the 643 retirements the agency predicted at the beginning of fiscal 2007, though it upped its estimate twice during the year, to 700 and then 800.

The union said it found another 24 who confirmed their retirements before Sept. 30 but have not yet shown up in agency retirement records. Union spokesman Doug Church added that only 16 of all the year's retirees had reached 56, the mandatory retirement age.

In addition, during September 2006 — the month before fiscal 2007 — 97 controllers retired, compared with the 39 the FAA predicted, according to the Transportation Department inspector general, who said the jump "was a result of the breakdown in contract talks."

That month began with the FAA ending an impasse in negotiations by imposing a contract with new work rules, including staffing cuts and a dress code, and a 30 percent cut in the pay of starting controllers. The agency tossed out staffing levels negotiated in the 1998 contract, and targeted all 314 control facilities for staff cuts, ranging from 9 percent to 26 percent.

"The surge in retirements just shows that the FAA's imposed work rules and pay system have exacerbated an already critical staffing issue," union president Forrey said. "Now we have controllers retiring with five and six years of eligible service left because they can't stand the environment any more, the Draconian work rules, six-day workweeks and forced overtime. They're concerned about making a big mistake due to the fatigue."

Meantime, an unpublished survey of 24,000 commercial and private pilots by the National Aeronautics and Space Administration found the pilots reported at least twice as many bird strikes, airborne near-collisions and runway errors as other government monitoring systems show, according to a person familiar with the results who was not authorized to discuss them publicly. The survey completed in 2005 also revealed higher-than-expected numbers of pilots who experienced "in-close approach changes" potentially dangerous, last-minute instructions to alter landing plans.

The FAA says it has long known fiscal 2007 would be the peak year for controllers hired in the early 1980s to become eligible for retirement. So it hired 1,815 new controllers during the year bringing the total to 18,874 now. The FAA said that total exceeded the year's target, but conceded it includes more than 3,000 controllers still in training who cannot handle all work stations at their facility.

"We're getting a lot of enthusiastic recruits," said the FAA's Sturgell. "Controller hiring, training and staffing is a major priority and we are on track to meet future traffic needs."

The FAA's Brown said estimating retirements is tricky, because controllers aren't forced to retire until 56 but are eligible at any age if they have 25 years service. She said the largest group retires once they have put in 25 years.

Brown denied the work force transformation compromised safety and noted that fatal accident rates in both commercial and private aviation are at record lows. She said staffing needed to be revised to reflect airline bankruptcies, mergers and flight pattern changes after the Sept. 11, 2001, terrorist attacks.

In addition to retirements, hundreds of veteran controllers were promoted to management jobs. Brown said she could not provide that number Friday, three weeks after fiscal year 2007 ended, because the agency was still manually calculating the year's promotions, resignations, firings and deaths.

The union, however, said 365 controllers were promoted to management jobs. It said another 337 resigned, were fired or died, but all most all of those were resignations and firings among new hires.

Except for experienced controllers hired from the military, most new controllers are trained six to eight months at the FAA academy in Oklahoma City, followed by on-the-job training that can last a couple months to three years before they are fully certified on all work stations at their facility.

Brown said the controller totals include more than 3,000 developmental controllers still receiving on-the-job training. She said these are an integral part of the work force because they are qualified to work solo on some stations.

But Church said the union's analysis of payroll data showed that about one-third of them had yet to qualify to work any station without a trainer supervising them.