Even before a casino bus crash caused an air traffic jam at UC Davis Medical Center last fall, medical helicopters had at least two close encounters with other aircraft near Sacramento in 2008, prompting anxious meetings among helicopter operators.

Both encounters required evasive action, although they did not qualify as near misses under Federal Aviation Administration rules.

The incidents underscore the work of California pilots who have quietly tried to reduce risks as the nationwide death toll from air medical crashes has swelled to at least 25 in 2008. Federal safety hearings are scheduled in February.

"We've never had a midair collision in California, but why would we wait for one?" said Graham Pierce, California director of PHI Air Medical and vice chairman of a statewide association of air medical companies and agencies.

That group, the California Association of Air Medical Services, has been pressing California hospitals to keep better track of incoming and outgoing flights. Yet at least one local hospital was unaware of the effort and another has been unwilling to say what it thinks of it.

Meanwhile, hospitals around the Sacramento region are poised to build more helicopter landing sites.

Kaiser said its landing pad, opening this fall, will serve its new trauma center in south Sacramento. Sutter plans to put one on the roof of its expanded downtown hospital in 2011. And Mercy Hospital of Folsom is raising money in hopes of eventually adding a landing site.

Scores of helicopters fly into and out of UC Davis Medical Center and Sutter Roseville Medical Center every month.

Sometimes the aircraft come uncomfortably close, can't keep track of who else might be approaching, or cross paths with law enforcement or fire aircraft that might not communicate on the same radio frequencies, pilots said.

"Overall, it's very safe," but steps need to be taken to make air medical transport even safer, said Sgt. David Magnino, who coordinates airborne emergency medical services for the California Highway Patrol. Two areas that need improvement, he said, are air-to-air communications and hospital monitoring of helicopter landing sites.

In June, two helicopters approaching the same Flagstaff, Ariz., hospital collided, killing all seven on board, but no one below.

In the Sacramento region, a series of episodes have worried some pilots, strengthening calls for better procedures.

Most recently, after the Oct. 5 casino bus crash in rural Colusa County injured dozens and killed seven at the scene, the helipad at UC Davis Medical Center got more traffic than it could handle. Two helicopters filled the landing site when another showed up, low on fuel, and a fourth may have been circling.

One helicopter left to refuel with its patient still on board, delaying the patient's arrival at an emergency room.

"As a flight officer, I would be very concerned about the traffic that was in and around and had to stay there" in the medical center's airspace that night, said Magnino.

Just six weeks before that, two helicopters responding to a crash on Highway 99 a little north of Sacramento flew so close to each other that one's "near collision" indicator started chiming.

"They were basically 100 feet below and 300 feet to the side of us, which for a helicopter is a little close," said Magnino. One of the aircraft was a CHP helicopter and the other was flown by REACH Air Medical Services.

The Aug. 23 incident didn't qualify as a "near miss," he said. The FAA confirmed that its rules are somewhat subjective, relying partly on pilot opinion.

Still, the episode was troubling enough to prompt a quickly scheduled meeting between REACH and the CHP, resulting in an interim agreement to monitor the same air-to-air frequency.

The CHP is "the first public agency to agree to that, which is really good," said Jim Adams, REACH's chief executive officer.

"What scares us," Adams said, is that public agencies that put helicopters in the air don't necessarily have the same radio equipment, use the same frequencies or answer to the same dispatch systems as private medical helicopters.

Call The Bee's Carrie Peyton Dahlberg, (916) 321-1086.