FORT LAUDERDALE, Fla. — In the past five years across the nation, three regional airline crashes killed 119 people. Three large airliners were destroyed in accidents and scores of planes came close to colliding.

Aviation safety has made great strides in the past decade. But each day pilots, air traffic controllers, ramp workers and other airline workers continue to commit dozens of errors, from controllers losing track of planes to pilots taking off with inadequate fuel.

Economic hardship caused by the Sept. 11, 2001, terrorist attacks and the current recession have strained the airline industry, contributing to inadequate training, pilot and controller fatigue, and a steady drain of experience, experts say.

Intense competition, incessant weather delays and tight security have applied even more pressure.

The Sun Sentinel reviewed hundreds of pilot and controller reports filed with a federal aviation-safety program, as well as accident reports investigated by National Transportation Safety Board.

“”We’ve maintained a fairly impressive safety record,”” saidWilliam Voss, CEO of the Flight Safety Foundation, an independent, nonprofit organization that monitors aviation safety. “”But the safety improvements have stopped. The overstressed airline community might have a limit as to how much it can take.””

Congress is on the verge of approving a far-reaching aviation bill. It would upgrade air traffic control and require more-stringent training for pilots and more experience for co-pilots.

Still, some in the aviation world are uneasy about the immediate future.

“”We’d be naive if we weren’t watching closely and being concerned,”” Voss said.

The airlines’ safety record has been excellent in the past five years, with about 0.02 fatal accidents per 100,000 departures, according to the NTSB.

Still, the industry continues to be plagued by glitches. Since 2005, more than 17,000 have been detailed in the Aviation Safety Reporting System, a joint venture between the Federal Aviation Administration and NASA that accepts anonymous reports.

The problems often involve pilots straying from their assigned altitude, controllers failing to keep two planes far enough apart or ramp workers allowing planes on the ground to bump into each other.

But they also include pilots confessing they dozed off at the controls and controllers losing their radar scopes because of a power failure.

Most errors end without harm but still pose danger.

In June, controllers ordered the pilots of a 737 to make a rapid descent from 24,000 feet, while the plane was 50 miles from Palm Beach International Airport in Florida. The flight was then instructed to make a night landing on a 6,900-foot runway, which the captain thought was too short. The runway had no instrument landing system, and the co-pilot had only 100 hours of experience flying that type of jetliner.

“”The last thing I wanted was to be high and fast to a short runway with no instrument landing system at night with a new guy flying,”” the captain wrote. “”This was unsafe controlling as far as I’m concerned.””

The plane landed safely.

In another instance, in February 2008, the pilots of a Boeing 737 airliner were instructed to take off at an intersection rather than use the full 9,000-foot runway at Fort Lauderdale-Hollywood International Airport. However, the pilots had loaded the jetliner with fuel and needed an additional quarter-mile of runway to ensure safety. The plane took off overweight.

Aviation safety officials consider glitches to be precursors of potential accidents. They encourage pilots, controllers and others to report the problems and avoid punitive action.

“”We want to find things that have gone wrong and prevent them from happening again,”” saidAlison Duquette, an FAA spokeswoman.

In the past year, the airlines have had a series of serious accidents and incidents.

As recently as March 27, a United Airlines Boeing 777 came within 200 feet of colliding in the air with a small plane that flew into its path near San Francisco International Airport.

In December, an American 737 that had departed Miami skidded off a runway in Kingston, Jamaica, during a rainstorm, injuring 15 of the 154 people on board.

Then there was the crash of a Continental Connection turboprop in February 2009. The regional airliner was attempting to land in Buffalo, N.Y., in snow, fog and darkness and plummeted six miles short of the runway. All 49 people on board and one person on the ground were killed.

The accident spurred the FAA to propose several changes in airline procedures, among them tightening pilot flight-duty time.

Taking into account the time pilots spend preparing for a flight, they might have to land a plane in bad weather and at night after being on the job 16 hours, saidJohn Prater, president of the Air Line Pilots Association.

“”That’s when we’re making our most critical decisions: on landing,”” said Prater, whose association represents 53,000 pilots working for 38 carriers in the United States and Canada.

The FAA is studying whether to increase the amount of flight experience co-pilots must have, as well as requiring more-stringent pilot training in flight simulators.

Members of Congress would like to see pilots subjected to stricter standards before being allowed to take command of an aircraft.

Larry Mussman, a former Spirit Airlines captain, said another problem pilots can face is a lack of authority to cancel flights if they think weather or mechanical conditions are unsafe.

“”If you don’t fly it, get it home to base, they’ll find a way to fire you,”” said Mussman, who today runs an aircraft service company.

Prater foresees a pilot shortage within the next three years.

The stress is causing many experienced pilots to call it quits before retirement, he said.

And fewer young people, including those in the military, are looking to the airlines for a career because of low pay and a lack of job security, he said.

“”Being a pilot can be a good job, but an absolutely horrible career,”” Prater said.

In 2004, air traffic controllers also predicted a severe staffing shortage. They said they were overwhelmed, and half of their 15,000 members were becoming eligible for retirement or early retirement. Because of the mental stamina and quick reactions required on the job, controllers must retire by age 56.

But after being awarded a new contract last year, many of those who had some years left before mandatory retirement decided to remain on the job, “”stabilizing the work force,”” saidDoug Church, spokesman for the National Air Traffic Controllers Association.

Controllers must work under grueling pressure, and as a result, they make mistakes. For instance, they might not coordinate with other controllers when guiding planes through radar sectors, or they might fail to provide clear instructions to pilots.

One of the most common errors is allowing planes approaching a runway to get closer than the required three miles apart, saidDale Wright, director of safety and technology for the National Air Traffic Controllers Association.

In about 10 years, a new satellite-based system called NextGen will allow planes to fly closer together without jeopardizing safety, Wright said.

Sometimes, controllers lose track of planes on the ground.

In August 2006, the single controller working in the tower of the Lexington, Ky., airport, cleared a Comair jet for takeoff early one morning. Because he was paying attention to his radar duties at the time, he didn’t watch the plane taxi on to the wrong runway.

The jet crashed, killing 49 people on board. Only the co-pilot,James Polehinkesurvived.

Although the NTSB faulted the pilots, it said the controller played a role.

Church said serious controller errors have been sharply reduced in the past year. To some extent, that was because air traffic was down more than 7 percent from 2008 to 2009. In large part, it was because controllers now anonymously report even the smallest errors to the FAA, he said.

That, in turn, has allowed the FAA and the controllers to study trends and make corrections, he said. For instance, the number of instances where a plane or vehicle rolls onto an active runway was down from 15 in 2008 to three in 2009.

“”That’s a good thing,”” he said. “”Things are far from perfect, but we feel they’re headed in the right direction.””