The system being TSO'd only means it will perform within certain accuracy limits as specified in the TSO. There is know way to know how the system is performing within those limits, like RNP can. So basic GPS protection areas have to cater for the worst performing TSO'd system.
A system being TSO'd has nothing to do with accuracy alone, more to do with accuracy vs performance
Yes I agree that QFF could navigate the Mantl 1 with the same perceived accuracy. And 90% of the time that might be the case. But protection areas are based on 3SD containment (99.7%) and on paper the figures reveal a wider protection area is required.
Last edited by alphacentauri; 6th Jun 2012 at 01:45.