Far more veteran air traffic controllers than the government expected have retired since the Bush administration imposed a contract on their union in 2006, new data show.

While veteran controllers bail out in unprecedented numbers and air travelers experience record delays, the Federal Aviation Administration has issued a series of all-is-well pronouncements about its work force.

The National Air Traffic Controllers Association, by contrast, has produced a stream of warnings about safety risks to the public from overworked controllers in major air control centers it says are undermanned.

One thing is certain: A veteran force of controllers, mostly hired in the early 1980s after President Ronald Reagan fired 11,000 members of a predecessor controllers union, is being replaced by lower-paid, less experienced young controllers and 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, although FAA spokeswoman Laura Brown denied this 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."

A total of 828 controllers retired in the 12 months that ended Sept. 30, the FAA said late Friday. The agency had predicted 643 retirements 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 to 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 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 Patrick 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."

The FAA views the retirements differently. The agency had 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 and now employs 14,874 controllers, exceeding the year's target, it said.

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

The FAA's 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.