Saturday's disappearance of a Malaysia Airlines 777 jet echoes an incident in 2007, when a Boeing 737 with 102 people on board disappeared during a flight between two Indonesian cities.
In that case, investigators determined that the Adam Air jet crashed into the ocean after pilots became distracted by issues with the navigation system, accidentally turned the autopilot off, and lost control of the plane. All those on board were lost, and it took more than a week for searchers to locate wreckage.
Aviation safety expert Todd Curtis, founder and publisher of AirSafe.com, said that was the most recent precedent for the circumstances now surrounding the case of Malaysia Airlines Flight 370, with 239 people aboard. The jet was en route from Kuala Lumpur to Beijing when contact with ground controllers was lost about two hours into the nearly six-hour flight.
If the plane went down, an emergency locator transmitter, or ELT, should automatically switch on to help rescuers pinpoint the site of the crash. Such signals are meant to alert aircraft flying overhead and even satellites, and should continue broadcasting for 30 days, Curtis said.
The jet also may have "painted" its location on the radar screen at the time of its disappearance, giving searchers a good idea of where to look, said aviation consultant and former pilot Keith Mackey.
"An aircraft the size of a 777 should be very easy to spot in normal conditions even if it were in a jungle," Mackey said. "It should not take that long to do, yet there are a lot of unknowns."
The case of Adam Air illustrates what can go wrong: Investigators suspect that the 737's locator beacon was damaged by the crash or affected by interference.
The 777, one of Boeing’s best-selling models, has had a very strong safety record, with just one fatal crash — last year’s Asiana Airlines crash at San Francisco International Airport — reported out of 6.9 million flights, according to data compiled by AirSafe.com. Three of the Asiana jet's 291 passengers — all teenage girls from China — were killed in that accident.
Based on precedent, Curtis said aviation authorities in Malaysia, Vietnam and China would be coordinating the search effort for the Malaysia Airlines 777 jet. Social-media postings from the region may well become a valuable information resource, he said.
"There could in fact be people who are putting their reports on Twitter even as we speak," he told NBC News.
NBC News' James Eng contributed to this report.