MASON, Ohio -- On April 30, 2007, two cars collided in Mason. A 16-year-old was seriously hurt and required medical helicopter transport.

A CareFlight helicopter from Miami Valley Hospital in Dayton began a 15-minute flight to pick up the teen.

But as that helicopter was en route, a University Hospital AirCare helicopter sat on its helipad in West Chester, less than two minutes' flight time away from the scene.

"The paramedics thought the CareFlight helicopter was in Warren County. But it was actually coming out of Dayton, which they weren't aware of," Dr. Jonathan VanZile, medical director of Mason Life Squad, said of the incident.

But Target 5 discovered that from January 2006 until September of this year, Mason requested Miami Valley's Careflight 14 times. Aircare out of UC was called just four times.

AirCare's medical director wasn't surprised.

"There are a lot of informal relationships and things that dictate those sort of things, but there is not a formal rule. It's essentially the person who's calling can call whoever they want to call," Dr. Bill Hinckley said.

Trauma patients, especially those with insurance, can mean big money for hospitals, and hospitals with helicopters work to build relationships with fire departments.

There is competition among hospitals for their medical helicopters to be called to a scene, but emergency room doctors say that's not their concern.

"Our goal is quite simple. It's to get the patient to where they can be definitively cared for as quickly as possible regardless of which hospital that is," Dr. Arthur Pancioli, a UC ER doctor, said.

In the Mason crash, the injured teen was flown back to the level 1 trauma center at MVH for treatment, even though University Hospital's level 1 trauma center was 15 miles closer to the scene.

"It's all about the patient. If minutes matter and the patients' lives are on the line, we want to be as quick as possible and sometimes that means going to the closest hospital, even if it's not your hospital," Pancioli said.

As this report prepared to air Wednesday, the city of Mason made a change to its policy, saying that AirCare dispatch will now be called first and will make the decision which helicopter can "provide the most expedient care to a critically injured or ill patient."

"It was concerning to us, especially when we started looking at some of these cases and the times and those kind of things," Dr. VanZile said. "What we found sometimes is Careflight was coming out of Dayton, which takes a long time, and then they were taking the patients back to Dayton."

For its part, Miami Valley Hospital told News 5, "The decision regarding which hospital the patient is taken is based on what's best for the patient, factoring in time, distance and weather as well as the capabilities of the trauma center."