U.K. CAA Proposing Three Phases for SSR Mode S Introduction

The U.K. Civil Aviation Authority (CAA) is now proposing to gradually expand the use of SSR (secondary surveillance radar) Mode S (select) in three phases in order to improve the "technical interaction between disparate airspace users without the need for a wholesale expansion of controlled airspace."

The Authority made the decision after considering some 3,000 responses to an impact assessment last year, and further discussion with general aviation associations, National Air Traffic Services (NATS) and the Ministry of Defense.

Phase One

The first phase would change the compliance date for SSR Mode S to March 31, 2008.  To gain access to the current mandatory transponder carriage airspace, all aircraft will need to be upgraded to Mode S after this date. There will be a four year transition period from March 2008 during which upgrades of existing transponders can be completed, but all new installations of SSR equipment, or where new aircraft are being brought into service with an SSR transponder already installed, will have to be Mode S compliant after the end of March 2008.

Phase Two

The CAA intends to conduct further public consultation on its policy aim to expand the requirement to carry and operate SSR transponders. This consultation will seek views on the following proposals:

• All VFR flights conducted within controlled airspace must be equipped with SSR Mode S transponders.
• The establishment of TMZs (transponder mandatory zones) within specific portions of uncontrolled airspace in order to mitigate specific risks within these areas while minimally affecting uncontrolled airspace.
• All international flights conducted by powered aircraft must operate with SSR Mode S.
• Gliders will no longer be exempt from transponder carriage requirements.

Future Implementation

The Authority envisages that the phased implementation will proceed beyond Phase Two with the aim of expanding SSR transponder carriage throughout all U.K. airspace for all aircraft.

More details can be found by clicking here.  05-28-2007.

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