Mode S update

The CAA appears to be moving away from a blanket introduction of Mode S next year to a phased approach which might not include all classes of aircraft for a number of years, particularly those which have little or no battery availability to power a transponder.It is envisaged that a first phase could be the

introduction of Mode S as the means of compliance in airspace where

the carriage of transponders is already mandated, and subsequent phases could

then expand the airspace in which the carriage and operation of transponders

is mandatory to include Class D and mandatory carriage zones. The CAA says this would specifically address identified safety concerns. Further

proposals, says the authority, would consider the impact of airspace utilisation and user

requirements on interoperability requirements and transponder

carriage regulation.The CAA adds that until suitable Low Power SSR Transponder (LPST) products are available at a reasonable price, ‘any applicability criteria and transitional arrangements would take into account the operational, technical and financial barriers that would preclude certain aircraft from carrying and operating an SSR transponder. Aircraft will not be grounded in 2008, or beyond, if suitable LPST units cannot be brought to market.’