FLARM

FLARM is an electronic device to selectively alert pilots to potential collisions between aircraft.

FLARM (the name being inspired from 'flight alarm') obtains its position from an integral GPS and a barometric sensor and then broadcasts this with forecast data about the future 3d flight track. Its receiver listens for other FLARM devices within typically 3-5 kilometres and processes the information received. Motion-prediction algorithms predict potential conflicts for up to 50 other signals and warn the pilot using sound and visual means. FLARM can also store information about static aerial obstacles, such as cables, in a database. The FLARM serial data protocol is public, while the prediction engine of the FLARM radio-protocol is proprietary and licensed to manufacturers. The prediction engine itself is patented by Onera (France).

Unlike conventional transponders in aircraft, FLARM has a low power consumption and is relatively cheap to buy (570 euro plus tax) and to install. Furthermore conventional Airborne Collision Avoidance Systems (ACAS) are little use in preventing gliders from colliding with each other because these aircraft are frequently close to each other without being in danger of collision. ACAS would be giving out continuous and unnecessary warnings in these circumstances, whereas FLARM only gives selective alerts to aircraft posing a collision risk. However the short range of the present power output makes FLARM unsuitable for avoiding collisions with fast moving aircraft.

FLARM was founded by Urs Rothacher and Andrea Schlapbach in 2003, joined by Urban Mäder in 2004. First sales were made in early 2004. Currently there are over 11,000 FLARM-compatible units (over 8,500 produced by FLARM Technology, over 2,500 by licensed 3rd party manufacturers who have now overtaken FLARM in current sales) in use mainly in Switzerland, Germany, France, Austria, Italy, the Benelux, Scandinavia, Hungary, Israel, Australia, New Zealand and South Africa. Since early 2007 it is being adopted in the UK after the telecom authority and Civil Aviation Authority confirmed that it was acceptable.

External links

* [http://www.flarm.com/product/index_en.html FLARM page]
* [http://www.flarm.com/support/manual/FLARM_DataportManual_v3.10E.pdf public FLARM serial data protocol]
* [http://www.bas.uk.net/data6.html Overview of collision avoidance systems]
* [http://www.flarm.com/files/transponders_en.pdf Comparison of Mode A/C, S, FLARM and ADS-B]
* [http://www.aerogazette.com/?p=170 "FIVV asks FLARM an open protocol" and "FLARM Compatibility Considerations" Aero Gazette]
* [http://groups.google.com/group/rec.aviation.soaring/msg/154644a88800ea28? Description of the Flarm radio protocol and related discussions]
* Enhancing the efficacy of Flarm radio communication protocol by computer simulation ( [http://www.xirrus.ch/download/efficacy_warning_system_lds2007.pdf English] , [http://www.wsl.ch/publikationen/pdf/8250.pdf German] )