The military helicopter crash in Southern California that left five Marines dead this week joins a long list aviation tragedies and near-disasters in the region, a busy hub for military and small aircraft.

In June 2022, three military aircraft crashes occurred in Southern California within a week. On June 3, U.S. Navy pilot Lt. Richard Bullock was killed when his F/A-18E Super Hornet crashed near Trona. Days later, five Marines on board a MV-22B Osprey died after the aircraft crashed in the California desert near the Arizona border during training. A Navy helicopter later crashed in the same region and all four crew members on board survived.

Last month, a Navy helicopter crashed off the coast of Coronado, California and all six people on board survived, military officials said.

California has also seen a number of high-profile accidents involving small planes and helicopters carrying civilians, like the January 2020 helicopter crash in Calabasas that killed Los Angeles Lakers legend Kobe Bryant and eight others. 

In July, six people died after a Cessna C550 business jet crashed and burst into flames in a field near the French Valley Airport in Murrieta, California, a city located between Los Angeles and San Diego. That crash came days after a 39-year-old man was killed and three children were injured when a small plane crashed near the same airport, officials said.

Experts say it's important to keep in mind how much military and civilian air traffic flies in the region.

Southern California experiences "an awful lot of military traffic," according to Jack Cress, an instructor in the Aviation Safety & Security Program at the University of Southern California and a former helicopter pilot in the U.S. Marine Corps. California is home to more than 30 federal military installations, according to the website of governor's military council.

Cress said that while the region's mountainous terrain and weather events like the atmospheric river can pose a challenge for pilots, the high traffic likely contributes to the number of accidents.

"Accident rates may be a little bit higher in California than others, but I would assume if it's the case, it would most likely be because of volume more than anything else," Cress said.

Cress said military accidents in this area are "pretty rare," but when they occur, they typically happen during tactical training, which he said can be very demanding. A CH-53E Super Stallion, the type of helicopter that went down in Pine Valley, was involved a 2018 crash near El Centro, California, close to the U.S.-Mexico border during a training mission. Military officials said all four crew members were believed to have died.

Meanwhile, a combination of improved manufacturing, design, technology as well as increased education and awareness has greatly improved safety in the aviation industry, according to Paul Deres, vice president of the Aircraft Owners and Pilots Association's Air Safety Institute.

On average, there are about 20 general aviation accidents each week in the United States and about a quarter of those are fatal crashes, according to Peter C. Knudson, a spokesperson for the National Transportation Safety Board. California has had more than 1,130 accidents, 239 of which were fatal, between 2012 and 2021, according to NTSB data.

"We are now living in the safest era ever in general aviation," Deres said.

Contributing: Christopher Cann and Natalie Neysa Alund, USA TODAY; Christopher Damien, Palm Springs Desert Sun

Maps:Missing Marines found dead in helicopter crash; maps show accident site near San Diego