SCHEDULE 5Radio communication and radio navigation equipment to be carried in aircraft

4.  The scales of radio communication and radio navigation equipment indicated in the Table at paragraph 3 are as follows—

(1)

Scale E1 was formerly defined as secondary surveillance radar equipment which includes a pressure altitude reporting transponder capable of operating in Mode A and Mode C and capable of being operated in accordance with such instructions as may be given to the aircraft by the air traffic control unit. There is no longer any requirement to carry Scale E1 but some aircraft may continue to carry it under a transitional exemption issued by the CAA.