Questions over the best way to protect civilian aircraft from surface-launched missiles have reemerged in light of the recent Malaysia Airlines tragedy over the Ukraine. On July 17, a medium-range Buk surface-to-air missile fired from the territory controlled by pro-Russia separatists reportedly struck Flight 17 en route from Amsterdam to Kuala Lumpur, Malaysia. The Boeing 777 crashed over eastern Ukraine, killing all 298 people on board.

A Congressional Research Service (CRS) report (pdf) published earlier this week revisits several airline-protection options that Congress, airlines and the military have considered over the past decade, only to conclude that these ideas are all still too expensive, impractical or ineffective. Here is a closer look at some of the options proposed to help prevent another catastrophe like Flight 17, as well as the most practical (and effective) idea yet: steering clear of trouble spots whenever possible.

Aircraft-mounted antimissile systems

It sounds like something out of a science-fiction movie: Lasers mounted to airliners that can help them elude attacking missiles launched from the ground or other aircraft.* The Department of Homeland Security (DHS) actually spent hundreds of millions of dollars several years ago to make this a reality. By 2008, the Federal Aviation Administration had certified two prototype directional infrared counter measure (DIRCM) systems designed to blind heat-seeking missiles’ navigation capabilities, giving an airliner a better chance of surviving such an attack.* This was not money well spent. Congress later shelved both BAE Systems’ Jeteye jamming laser beam and Northrup Grumman’s Guardian civilian airliner missile-defense system, citing reliability problems.

The CRS report also notes that a DIRCM system would not be able to intercept a radar-guided missile like the one that brought down Flight 17. “The DHS missile-protection effort did not focus on protections against radar-guided missiles, as these are rarely possessed by terrorists and insurgent groups,” according to the CRS. Obviously, times have changed. Regardless, U.S. airlines have likewise balked at the cost of DIRCM systems, estimating costs of more than $2 billion annually for a fleet-wide deployment. The Israeli government is still investigating the possibility of deploying similar technology on its country’s commercial aircraft, however.

Evasive maneuvers during takeoffs and landings

Pilots can use steep descents, rapid climbs and tight takeoff and landing patterns to cut down the time spent flying over conflict zones where they are within range of smaller, man-portable surface-to-air weapons. Such maneuvers are hardly foolproof, the CRS report points out. A shoulder-fired missile hit a DHL cargo jet making a steep climb while departing Baghdad in November 2003, for example. Fortunately, the aircraft was able to return to the airport and make an emergency landing.

Iron Dome-like surface-fired air defense systems

Other options to protect commercial aircraft include ground-based defenses stationed near airports, such as Israel’s Iron Dome. Iron Dome has been operational since March 2011 and has had some success firing interceptor rockets to destroy incoming missiles, although the CRS report notes skepticism about the technology’s effectiveness. Homeland Security considered installing laser-based missile defense such as DIRCM in drone aircraft stationed at high altitudes above airports. Testing of such systems, however, found that they couldn’t reliably detect or deflect shoulder-fired missiles.*

Regardless of which protective measures airlines and airports adopt, Flight 17 highlights a very real threat that has emerged over the past 40 years. More than 40 civilian aircraft have been hit by shoulder fired-missiles, causing 25 crashes and more than 600 deaths since the 1970s, according to a 2005 U.S. State Department report.

Most of these incidents involved small aircraft operated at low altitudes in areas of ongoing armed conflicts. Still, larger aircraft have been hit, including a Boeing 727 in the Democratic Republic of Congo in October 1998. That Lignes Aériennes Congolaises crashed just after takeoff from Kindu Airport, killing all 41 people on board. On November 28, 2002, terrorists launched two shoulder-fired missiles at an Israeli chartered Boeing 757 departing Mombasa, Kenya. Although both missiles missed their target, this was the first time such an event had taken place outside of a conflict zone and the incident spurred on the U.S.’s efforts to develop and deploy DIRCM systems, according to the CSR report.

Absent a high-tech solution, the FAA’s best bet for protecting U.S. airliners is to warn them of dangerous airspace or ban them from traveling through those areas. The agency prohibits flights by U.S. operators in and near areas of Libya, Iraq, Somalia, Ethiopia and Ukraine. Syria and Afghanistan are also places to be avoided, although there are no bans in place.

*Editor's Note (8/4/14): These sentences were edited after posting. The originals implied that the goal of directional infrared countermeasure (DIRCM) systems is to shoot down attacking missiles. Rather, DIRCM systems use an infrared beam to interfere with a heat-seeking missile’s navigation systems.