An International Civil Aviation Organization (ICAO) working group is recommending that new aircraft delivered after 2020 come equipped with a tracking data broadcast system that sends regular position updates to airline operators, a flight data recorder that automatically deploys (and floats) after a crash and a tamperproof distress reporting unit that will transmit aircraft position and identification to a global network of rescue coordination centers when unusual attitudes, speeds or accelerations or other triggered events occur.

The airborne equipment, coupled with new global information sharing networks for air traffic service providers and rescue coordination centers, is being called the Global Aeronautical Distress and Safety Systems (GADSS).

The Ad Hoc Working Group (AHWG) on Aircraft Tracking, formed by ICAO in May in the wake of the disappearance of Malaysia Airlines Flight MH370 in early March, will present its draft report on the high-level requirements and concept of operations for the Global Aeronautical Distress and Safety System (GADSS) to the broader aviation community at ICAO’s high level safety conference next month in Montreal. The group, which is working in conjunction with the International Air Transport Association’s (IATA)Aircraft Tracking Task Force (ATTF), will ask ICAO to finalize the concept of operations as a first step to creating new rules.

The 2020 forward-fit equipage target would be part of a phased-in approach to improving airlines, air traffic controller and rescue services situational awareness of transport aircraft, particularly when flying over remote and oceanic areas where position reporting is often ad hoc. The recommendations work hand-in-glove with the ATTF’s final recommendations, which call for near-term voluntary tracking of aircraft at least every 15 min., largely with existing onboard equipment. Voluntary tracking is incorporated in the AHWG’s recommendations for the next 2-5 years. The longer term plans call for a “target” or ideal state of the GADSS around 2025, which appears to give more time for airlines to retrofit some of the systems into existing fleets and for countries to upgrade air traffic control and rescue operations.

Once operational, the system would work like this: At takeoff the tracking system begins sending position, time and identification information at least every 15 min. to the airline’s operational control center (AOC), potentially using a third-party company to provide the tracking services. That data long term would be available to the airline using System-wide Information Management (SWIM)-enabled applications.

At some point in the flight, airspeed slows and the stall avoidance system issues an alert, causing the tracking system to automatically enter the “abnormal” mode and begin sending position, time and identification updates at approximately 1 min. updates.

The tracking provider would alert the AOC of an abnormal event, and the AOC would alert air traffic control (ATC). ATC would more closely monitor the aircraft and alert the correct Rescue Coordination Center (RCC) of a potential issue. If aircraft problems continue, for example airspeed continues to slow and the aircraft is descending at 7,000 fpm, the tamper-proof autonomous distress tracking system automatically triggers and alerts both the AOC and ATC of the “distress event” and ATC alerts the RCC, which initiates a search and rescue response with the tracking data. 

The distress tracking system provides position and time reports “or distinctive signals from which the 4D position can be derived” on protected frequencies, says the AHWG. The system is either automatically activated or may be manually activated, although in cases of false alarm, it can only be deactivated by “the activating mechanism.” 

In the long term using SWIM, applications, the tracking data in distress mode would automatically broadcast globally, but only to entities with agreed upon access, with the aircraft position information used to automatically notify the required ATC facilities and the correct RCC

If an accident were to occur, the automatic deployable recorders would eject, and in cases of a ditching, float on the surface while transmitting a 406MHz emergency locator transmitter signal with position and identification information to the COSPAS-SARSAT satellite network, which sends the same information to the RCC to home in on the crash site.

In the case of MH370, surveillance data was initially lost less than one hour after takeoff from Kuala Lumpur on a flight to Beijing, possibly due to on board failures or deliberate actions. The search for the aircraft continues off the west coast of Australia, where analysis of satellite communication system pings indicate the aircraft most likely ended up 7 hours after primary radar contact was lost. 

Communications with the crew had ceased earlier, followed by the loss of on board transponder signals used by ground-based secondary surveillance radar for tracking, and an unplanned and abnormal route change. Given that the aircraft was in radar coverage, it was not using satellite-based data communications for position reporting.

“Global tracking of airline flights should be pursued as a matter of priority to provide early notice of, and response to, abnormal flight behavior,” says the AHWG in its report, noting that the enhancements will represent a “large financial cost” to the industry, but one that will offset by more effect search, rescue and recovery services, “additional benefits” for air traffic management, airline operations and public confidence.