The disappearance of the Malaysia Airlines flight over the Indian Ocean earlier this year has ignited a discussion in the aviation community regarding the tracking of aircraft outside of normal radar range, says David Williams.
Currently, there are a number of areas of the world which are outside of ground-based radar tracking stations and aircrafts must periodically report their location to air traffic control.
A system which is used for communication, both outside and under radar contact, is the aircraft communications, addressing, and reporting system (ACARS). This is a digital communications datalink for the transmissions of messages between the aircraft and ground stations.
The system was originally developed for Air Traffic Control’s (ATC) issue of clearances and instructions to aircraft and it has been expanded to include messages between the aircraft and the aircraft’s company base.
The system uses alpha numeric text messages which are similar to twitter messages sent between smart phones over a cellular phone system. Transmissions are limited to a specific format consisting of a maximum 220 characters per message and are burst transmitted lasting less than 1 second. ACARS continues to be improved and is used in many instances to communicate messages such as aircraft status position, technical performance data, abnormal aircraft system status, weather, and also loading and trim information.
ACARS uses a data link service provider (DSP) which is responsible for the movement of these messages by radio link (VHF or HF) or by satellite communications between the sender and receiver. The primary DSPs are Aeronautical Radio, Inc. (ARINC) and Societe Internationale de Telecommunications Aeronautiques (SITA). Due to the limited distance of radio transmission, satellite DSP companies have now entered the datalink service provider arena. For example, companies such as INMARSAT and IRIDIUM provide worldwide data link capability through the use of satellite communications.
Both the International Civil Aviation Organization (ICAO) and the International Air Transport Association (IATA), the world’s leading aviation organizations, are recommending real-time global tracking of airliners. Earlier this year international aviation officials met in Montréal where they endorsed universal tracking of airliners. Since the meeting ICAO has formed a panel of international aviation experts, known as the Aircraft Tracking Task Force (ATTF) which will submit its recommendations for enhanced global aircraft tracking to ICAO. Meanwhile, the European Commission (EC) has supported plans to increase the tracking of commercial airliners following a meeting of European Union (EU) transportation ministers. The EC indicated EU aviation safety regulations will be made in 2015 and one of the regulations will make it impossible to disable the tracking system during flight.
Only a few airlines rely on existing satellite and aircraft communication systems to provide full-time position information for airliners. In an effort to speed up adoption of real-time tracking, INMARSAT, the UK-based company whose network tracked the digital pings from MH370, has offered tracking services to the airlines free of charge. Approximately 11,000 current airliners have INMARSAT antennas installed but all are not using the tracking service.
Meanwhile, additional solutions to improve aircraft accident investigation currently being considered are; to increase the battery life on the cockpit voice recorder (CVR) and flight data recorder (FDR) from the present 30 days to 90 days, and to increase the recording time on the CVR from two hours to 20 hours.
A service which INMARSAT is offering is a “cloud-based black box”. This service would be a quantum leap forward and will allow aircraft to stream real-time data about the aircraft systems which are normally recorded by the on-board “black boxes”. Having the FDR and the CVR information available without having to find the physical box would eliminate the “what happened?” issues in aircraft accidents.
This article is taken from AGCS’ forthcoming Global Aviation Safety Study, which will be released later this year.
E. DAVID WILLIAMS
David Williams is Assistant Professor of Aerospace and Occupational Safety at Embry-Riddle Aeronautical University, Daytona Beach, Florida. Teaching courses
in Aviation Safety, Aircraft Crash and Emergency Management, Airport Safety and Security Operations, and Risk Management and Insurance. Former Airport Executive Director and Chairman of Airport Board; risk manager and loss control specialist; USAF pilot with commercial, multi-engine and instrument airman’s certificate.