(CNN) - The number of people killed in US aviation accidents increased by 13% from 2017 to 2018, according to the National Transportation Safety Board.
The NTSB reported 347 people died in aviation accidents in 2017, compared to 393 in 2018.
"The NTSB is disappointed to see that the fatal accident rate and fatal accident numbers have increased overall for last year," NTSB Chairman Robert L. Sumwalt told CNN. "The rate is once again above one fatality per 100,000 flight hours."
Most of the fatalities occurred during general aviation, which includes private and recreational flying. For two years, the fatal accident rate among general aviation was below 1.0 per 100,000 flight hours. It increased to 1.029 accidents per 100,000 flight hours in 2018.
Meanwhile, fatalities in On-Demand Part 135 operations -- which include charters, air taxis and air tours -- claimed 12 lives, down from 16 in 2017.
The commercial airline accident rate has gone significantly down in the last decade, according to Sumwalt.
The 2018 death of Wells Fargo executive Jennifer Riordan aboard a Southwest Airlines was the country's first commercial airline passenger fatality in nine years.
"It's a very good safety record, but still, one fatality is certainly one too many," Sumwalt said.
The NTSB did not provide reasons for the increase in aviation fatalities, but has issued recommendations for improving safety aboard general aviation and Part 135 operations.
One safety proposal is for charter operators to start using safety management systems that provide a formal approach to managing aircraft safety. Charter operators are also urged to employ flight data monitoring programs, which help detect problems before a crash.
"Our real mission is to investigate transportation accidents to determine the probable cause, and most importantly issue safety recommendations so that they don't happen again," Sumwalt said.