Why Passenger Planes Can Still Vanish

By Dec. 30, when search teams began to recover debris and bodies from the apparent crash site of AirAsia flight QZ8501, the airline industry had begun to hear renewed calls from flyers and regulators for more precise, consistent tracking of commercial aircraft. During inclement weather two days earlier, the Airbus A320, while carrying 162 people from Surabaya in Indonesia to Singapore, had dropped off radar and couldn’t be found.

More than three-quarters of the earth’s surface, including large parts of Africa, Asia, and South America as well as most of the oceans, lacks reliable radar coverage. In March, when a Malaysia Airlines Boeing 777 bound for China disappeared, airlines and regulators began to grapple with the fact that a plane without a working transponder can be virtually invisible. Most new aircraft include technologies that bridge the radar gap, but many older planes still don’t have them. The International Air Transport Association, a trade group that represents 250 airlines, emphasizes that almost all the 100,000 flights per day travel without incident.