A debate about the need for global flight-tracking and data streaming is back on the airwaves after AirAsia flight QZ8501 disappeared from radar on Dec. 28 and the Airbus A320’s emergency locator transmitters failed to emit signals before entering the Java Sea. Debris and bodies from flight QZ8501 were located off the coast of Borneo on Dec. 30, three days after air traffic controllers lost voice and positioning from radar, but questions as to how and why a state-of-the-art aircraft can "vanish" in the first place are being raised again, just seven months after a Malaysia Airlines Boeing 777-200 disappeared.

Key differences between MH370 and QZ8501 are apparent from the start, however. QZ8501, according to reports, was being tracked by secondary surveillance radar (which gives identification, position and altitude every 8-16 sec.) and Automatic Dependent Surveillance-Broadcast (ADS-B "out") which provides that data and more every 1 sec. For MH370, that surveillance equipment onboard either failed or was turned off relatively early in the flight, which continued on for hours with no surveillance system activated. 

Despite having a fairly accurate position at altitude when surveillance stopped for QZ8501, the aircraft's high altitude and the drift of the ocean led to a large search area initially—seven square sectors each measuring 60 nm per side. Debris was ultimately found on the third day of searching near the last reported ADS-B position, according to early reports.

Emergency locator transmitters (ELT), which activate when g forces exceed a certain threshold, indicating a crash, have reliability issues to start with, and since the equipment is connected to the aircraft, it is of no use when the airframe is underwater.  

Based on early indications of the QZ8501 crash sequence, there are two solutions available today that may have helped, and both will likely be considered in the crash investigation that will follow. Individually or together, triggered flight-data transmissions and deployable flight recorders could quickly determine an aircraft's basic health, pre- or post-incident, or the position of a debris field. 

However, despite renewed pressure to act following MH370’s disappearance, neither technology is yet considered a “near-term” possibility, primarily due to the cost and time to retrofit the equipment into legacy fleets or build up substantial numbers of factory-equipped new aircraft.

A task force set up by the International Civil Aviation Organization (ICAO) in the wake of MH370 is due to publish global flight-tracking standards in 2016 after agreeing on a road map earlier this year, but industry observers say that there’s too much rhetoric and not enough action.

There are also long-term solutions available to the industry, which is clinging conservatively to its legacy computer systems. Storing flight data in a cloud that would be immediately available in the event of an aircraft accident or disappearance seems an obvious choice, but while inflight data-streaming is technically possible, institutional issues must be addressed first, including integrity, security and authenticity of the data.

Another game-changer, set for initial operation in 2018, is a combination of a new search-and-rescue satellite network and second-generation emergency locator transmitters that will transform the way distress signals are activated and detected and then generate responses. Equally game-changing are the second-generation ELTs that NASA and industry are now defining for introduction after 2016, devices that will have several new operating modes to help ensure that a distress signal actually is transmitted. 

These solutions could help end the massive searches that are launched when the unthinkable happens. Aviation Week & Space Technology explored global flight-tracking in detail in the Aug. 4, 2014, issue. Read the articles online.