Hawai'i experienced 10 aviation accidents in 2007, its lowest number in five years, according to National Transportation Safety Board data.

Five people died and 15 were injured in last year's accidents. The fatalities occurred in two tour helicopter crashes on Kaua'i in March 2007.

Half of the 10 aviation accidents involved helicopters flying as air taxi and commuter operators. Four involved fliers engaged in general aviation activities, and one a major air carrier.

That incident occurred Dec. 25 when a Northwest Airlines jet with 294 people aboard encountered severe turbulence during a flight from Osaka, Japan, to Honolulu. Two flight attendants and a passenger sustained injuries.

Because the annual number of aviation accidents can vary widely, and because the circumstances of each incident, such as type of aircraft and pilot experience, also are different in each case, it's difficult to draw conclusions based on a single year's data.

Even so, aircraft accidents and fatalities in Hawai'i appear to be on a downward trend.

In 2006 there were 13 aviation accidents and five deaths in Hawai'i; 16 accidents and six deaths in 2005; 15 accidents and nine deaths in 2004; and 14 accidents and 11 deaths in 2003.

The numbers for 2007 are below the 10-year averages from 1997 to 2006 of 12.1 aviation accidents and 7.3 deaths per year.

Ian Gregor of the Federal Aviation Administration's Western-Pacific Region said it is "encouraging" to see that the number of accidents in Hawai'i is down. However, air tour safety remains a concern, he said.

"We intensified our focus on Hawai'i air tour safety following last year's two fatal crashes. We established a safety inspection unit that is dedicated to air tour operations," Gregor said.

FAA safety officials met over several days this week in Honolulu with air tour operators and Helicopter Association International representatives to discuss possible improvements to operations and procedures. The first such meeting was held a year ago.

"The purpose of the meetings is to stress the importance of placing safety above everything else," Gregor said.

In 1996, the agency implemented a special air tour rule in Hawai'i called SFAR-71 that established a range of safety requirements and procedures for air tour operators.

These include requiring tour flights that travel over the ocean to be equipped with floats or to provide passengers with flotation gear. The rules also set a minimum altitude of 1,500 feet and mandate that pilots file a helicopter performance plan before each flight and that passengers be given a briefing on water-ditching procedures.

He said because the rules were so effective in substantially decreasing the number of air tour accidents and fatalities in Hawai'i, the regulation last year was extended to air tour operators across the country.

The NTSB has recommended additional rules for Hawai'i air tours, including mandatory training in local weather patterns for newly hired air tour pilots and increased oversight and additional safety requirements for air tour companies that operate under the general aviation category.

So far this year, the NTSB has listed four aviation accidents, including the Jan. 14 death of a mail cargo plane pilot who ditched in the ocean off Kaua'i, and a Feb. 13 go! airline flight with 43 aboard that overshot the Hilo Airport by 15 miles before turning back and landing safely. Both incidents remain under investigation.

The 2008 list does not yet include yesterday's emergency landing of a single-engine tour airplane in Kalapana on the Big Island. The Island Hoppers plane with seven aboard, including six passengers, landed safely on Highway 130 after the pilot reported engine failure, the Hawai'i County Fire Department said. The plane was not damaged and no one was hurt, the Fire Department said.