SCAT-1 trials with ground-based augmentation systems (GBAS) were run by the US Federal Aviation Administration working with Continental Airlines in the 1990s, but abandoned when the FAA decided that wide area augmentation systems could produce Cat I approaches more cheaply. The US agency and postponed its GBAS programme known as LAAS (local area augmentation system).
With LAAS still shelved, Airservices Australia, working with the FAA, looks likely to be the first into the field with a GBAS that will meet International Civil Aviation Organisation standards for a precision GNSS approach certificated for general public transport use. Qantas first flew a GBAS GNSS approach on a trial basis at Sydney airport in November last year, and trials continue with a target for certification to ICAO Annex 10 standards by the end of 2008, and this has the potential to achieve Cat II or Cat III decision heights. The SCAT-1 system needs special approval for individual installations, and Avinor's system has been approved by the European Aviation Safety Agency.
Source: Flight International
