There was nothing the pilots of Malaysia Airlines Flight MH17 could do once a missile locked onto it.
Theoretically, there are ways a hulking Boeing 777 could evade a missile like the one that brought the plane down over territory controlled by pro-Russian separatists, but experts say the systems are too costly and impractical for commercial jets.
Military planes are designed to take on the threat of surface-to-air missiles. They are typically equipped with countermeasures that release one of two types of decoys: chaff, a cloud of metallic material that can confuse radar-guided missiles like the SA-11 Buk believed to have brought down MH17, or chemical flares to distract heat-seeking missiles.
These anti-missile systems can help save a plane — but they're not infallible, and they're not designed for the massive global fleet of commercial aircraft.
"Unless we assume the world is at war constantly and all that airspace is a threat, it just doesn't make sense for the commercial world," Tom Casey, a former commercial pilot who flew Boeing 777s, told NBC News.
Bruce Rodger, the president of aviation consultancy Aero Consulting Experts, noted the extreme rarity of cases like MH17 and the 1983 downing of Korean Air Lines Flight 007 after it flew over Soviet airspace — even though "thousands and thousands" of planes are flying around the globe on any given day.
"And in this case, (MH17) unfortunately flew over airspace they should have avoided," Rodger said. "So situations like this, while very tragic, isn't something commercial airliners are likely to run into or plan for."
Plus, while it's impossible to estimate the percentage of successful attempts to avoid anti-aircraft missiles, Rodger said that the technology isn't a guarantee.
"They release decoys meant to distract the missile, so to speak," Rodger said. "It's not always successful. And the crew still needs to maneuver the craft away from the missile."
Casey said that anti-missile systems alone wouldn't be enough to save a plane.
Adding anti-missile technology "effectively turns (an aircraft) into a military transport," he said. And commercial pilots aren't,and arguably shouldn't be, trained for those situations, he said.
"Even if you added the technology, you'd need to train all commercial pilots on detection and process (for avoiding missiles)," Casey said. "The technology alone won't save you. And the people in the cockpit have enough to do without being burdened unnecessarily with lessons they won't need."
There is an exception: The Israeli commercial airline El Al, which rolled out anti-ballistic technology starting in 2004 and has continued to deploy new tests and systems.
Israel’s Ministry of Defense announced in February that it successfully tested something called the Commercial Multi-Spectral Infrared Countermeasures (C-MUSIC) system, which uses laser technology and thermal imaging to jam incoming threats. The system, however, only protects against shoulder-launched heat-seeking missiles and not the radar-guided missile that reportedly hit MH17.
“It essentially blinds the missile and throws it off course,” Matt Schroeder, senior analyst at the Federation of American Scientists, told NBC News. “Because the missiles are moving so quickly, all it needs to do is break the lock for a couple of seconds and the missile will miss the plane.”
The anti-missile technology "makes sense for Israel, which is a very specific situation given the tensions there," said Rodger, the Aero Consulting Experts president.
Overall, said former pilot Casey, "Peace treaties are a much better defense than hardware. But we don't have that right now."