By David Shepardson

WASHINGTON (Reuters) -A bipartisan group of three U.S. senators on Tuesday called for new funding to boost air traffic control staffing, speed training of new controllers and provide new incentives to retain aviation workers.

Democratic Senator Jeanne Shaheen and Republican Senators John Hoeven and Jerry Moran introduced legislation that would authorize $100 million over five years for tower simulators at Air Traffic Control facilities nationwide, which could reduce time needed to certify an air traffic controller by 27%.

Shaheen said the bill would "expand traffic controller workforce pipeline, enhance training facilities and equipment, improve recruitment and retention efforts."

A persistent shortage of controllers has delayed flights and, at many facilities, controllers are working mandatory overtime and six-day weeks to cover shifts.

The FAA is about 3,500 air traffic controllers short of targeted staffing levels and has about 10% fewer controllers than it did in 2012.

The funding the senators are calling for is focused on training and air traffic control hiring rather than the massive FAA facilities needs.

In March, former President Joe Biden proposed $8 billion over the next five years to replace or modernize more than 20 aging air traffic control facilities and 377 critical radar systems. A quarter of all FAA facilities are 50 years old or older.

The bill proposed on Tuesday also aims to improve controller mental health and approve up to $100 million in funding for collegiate controller training programs.

Moran, who chairs a key aviation subcommittee, said "continued investments in the programs and infrastructure supporting air traffic controllers will help to address workforce needs and keep our flying public safe.”

Earlier this month, Transportation Secretary Sean Duffy said he was reconsidering rules that had allowed air traffic control supervisors to reduce staffing at Washington's Reagan National Airport before a fatal Army helicopter-plane collision that killed 67 people in January.

Duffy, who is going to the FAA's air traffic control academy in Oklahoma City this week, plans to soon announce steps to surge more air traffic control training and applicants. He is considering new incentives to keep retirement-eligible controllers on the job or could propose to extend the mandatory retirement age for controllers, which is 56.

Last week, the U.S. aviation sector called for "robust emergency funding" from Congress for air traffic control technology and staffing after a series of crashes.

Last year, the FAA cut minimum flight requirements at congested New York City-area airports through October, citing air traffic controller staffing shortages.