Hawai'i has had six aviation accidents so far this year, including the missing Big Island plane, compared with 10 accidents in all of 2007, which was the lowest total in five years.

Five people died last year, and one this year before Tuesday's incident, according to the National Transportation Safety Board.

As the overall number of air accidents has declined, so has the number of crashes involving the air tour industry, which serves hundreds of thousands of visitors to the Islands annually.

Added safety measures, part of the Federal Aviation Administration's larger effort to improve safety in the air tour industry, have helped reduce air tour incidents, FAA spokesman Ian Gregor said.

"The FAA has paid an awful lot of attention to air tour safety — especially in Hawai'i — over the last 15 years," Gregor said.

According to the FAA, Hawai'i had two air tour accidents last year. According to the NTSB, only one of the accidents this year involved an air tour.

The FAA's campaign to improve air tour safety has centered around Hawai'i, one of the nation's biggest markets, he said.

In 1996, the FAA instituted SFAR-71, a set of rules that established safety requirements for Hawai'i's air tour operators, including life vests for passengers, preflight briefings and pilot experience standards.

"The number of air tour accidents dropped dramatically after we implemented those rules," Gregor said.

As a result, the rules have since been expanded to cover air tour operations across the country, he said.

The FAA has also taken other steps to ensure safety, including establishing an air tour inspection unit in Honolulu last year. The sole purpose of the unit is to conduct surveillance of aircraft and pilots of the state's air tour operations, Gregor said.

Across the nation, the number of air tour accidents has dropped in recent years. The nation saw eight air tour accidents in 2007, compared to an average of 13 accidents over each of the previous five years.

"The 2007 air tour accident number was the lowest level in more than two decades," Gregor said, which he described as "a very encouraging sign."

Former air tour pilot Mac Smith agreed that federal regulations have helped improve air tour safety. However, he also attributes fewer accidents to better operations by air tour operators and the high visibility of air crashes in Hawai'i.

"All the operators are interested in maintaining air safety because their people are getting on those planes as well," said Smith, who is now the chief instructor with Flight School Hawai'i.

As a result, "the industry has a very respectable record," he said.

However, some still feel that more needs to be done to ensure maximum safety for passengers.

U.S. Air Tour Association president Steve Bassett urged the FAA to re-evaluate SFAR-71, which set a minimum altitude of 1,500 feet for air tour carriers. Air tour operators across the state have opposed this requirement since the law was put into place, Bassett said.

"If you have bad weather conditions over high elevations, are forced into that high elevation and by regulation can't fly under that, you may be creating a less safe environment," he said.

The organization, based in Washington, D.C., represents commercial air tour operators throughout the country. It also provides education, training and networking opportunities for those in the industry.

Despite his opposition to the SFAR-71 rule, Bassett is optimistic about the future of the air tour industry, which he describes as "the most heavily regulated aviation activity in the world."

"If you look at air tour safety in relation to aviation safety, it has an extraordinary record. It always has and it always will," Bassett said.