(CNN) -- Jenni Rivera. Add the Mexican-American superstar's name to a long list of beloved celebrities killed in the crash of a charter aircraft.
That list includes singer/actress Aaliyah, golfer Payne Stewart and musicians Ronnie Van Zant, Buddy Holly and Ritchie Valens. In 2008, Travis Barker of Blink-182 and Adam "DJ AM" Goldstein were critically injured -- and four other passengers were killed -- when their charter jet crashed on takeoff in South Carolina.
Overall, the industry is overwhelmingly safe. Yet Sunday's crash in northern Mexico that killed Rivera and six others, including a pilot and co-pilot, has focused attention on charter safety.
One red flag, experts say, is the 43-year-old plane's age.
"The Learjet is a pretty reliable airplane, but this one was really old," says Ladd Sanger, an attorney and licensed pilot who specializes in plane crashes. "As a general rule, over 40 years old, and I think you need to be concerned."
However -- on its own -- age is not an indicator of an airplane's safety, says John McGraw. an ex-FAA deputy administrator.
"This plane was 10 minutes in flight, so you wouldn't expect that to be a factor in this type of accident," he said.
In general, experts say travelers can reduce their risk of choosing a charter that's poorly run -- or even illegal -- by asking a few smart questions.
Make sure the charter is well established and employs its own pilots, experts say. Leonard Goldberg is president and owner of Gold Aviation, a 17-year-old outfit based in Ft. Lauderdale, Florida, that flies six aircraft. "Our search process is very stringent," he says. "We see dozens of candidates at least before we settle on a pilot, which is pretty common, for good quality operators."
The FAA doesn't impose age limits for charter pilots, although pilots for airliners and other commercial carriers must retire at age 64. Charter pilots must pass flight medical exams, which increase in frequency with age.
In the United States, ask to see the charter operator's FAA Part 135 air carrier certificate. It's what legally defines an operator as a charter carrier. "It should be posted inside their building," Sanger says.
Be aware that if you use a broker instead of booking directly from a charter operator, you're putting your journey in the hands of a middleman. Critics call it "jet roulette" because you're essentially trusting the broker to hire a safe and legal charter plane.
Ask charter operators if their firm performs its own aircraft maintenance. Find out if training for the charter company's mechanics is approved by the aircraft manufacturers.
Many charters and brokers hire outside companies to oversee, rate and suggest improvements for their safety practices. Ask about safety audits.
Sanger says he has seen more than his share of illegal "bootleg" charter operations, and one way to easily smoke them out is to ask about their insurance liability. Depending on the value of the plane, Goldberg says look for a range between $5 million and $300 million. "Get a copy of the policy," Sanger says."If they don't have at least a $10 million policy and you're chartering a jet -- run."
The FAA does require charter companies to carry insurance. But it does not require insurance for non-charter private planes.
That makes it very tempting, Sanger says, for private plane owners to rake in fat profits by pretending to be a legal charter operator.
"They need to pass a law that says you have to have insurance on any airplane, just like they do cars," he says.
When contracting with a non-U.S. charter operator, it gets more complicated. Rules and regulations are different in every country, underscoring the importance of grilling the operator about maintenance, documentation and oversight. Appearances can mean a lot. "Sometimes all you need to do is look at a plane to know you don't want to get on it," Sanger said.
Deadly charter accidents increased in the United States last year, according to the FAA, up from six fatal accidents in 2010 to 16 in 2011, when pilots logged more than 3 million hours in flight. Deaths rose from 17 to 41.
Worldwide so far this year, out of more than 17,600 business jets -- which include small private and charter planes -- there have been 12 major accidents and 25 deaths, according to the Flight Safety Foundation.
CNN's Mike Ahlers, Mariano Castillo and Aaron Cooper contributed to this report.