TRANSPONDERS

Requirements for the Operation of Transponders 

91.247 Use of transponder and altitude reporting equipment

(A) A pilot-in-command of an aircraft operating in transponder mandatory special use airspace or transponder mandatory controlled airspace  within the New Zealand FIR must, unless otherwise authorised or instructed by ATC, operate the transponder —

(1) in Mode A and Mode C; or

(2) in Mode S if the aircraft is equipped with Mode S equipment and allocated a unique Mode S code referred to in paragraph (d); or

(3) to transmit ADS-B data, if the aircraft is equipped with an ADSB system that meets the requirements under rule 91.257.

(C) The pilot-in-command must set the transponder SSR code—

(1) to the code assigned by ATC for the flight; or

(2) if not assigned a code by ATC, in accordance with Table 2; and

(3) in the event of an in-flight emergency, loss of radio communications, or an act of unlawful interference, set the transponder to the appropriate code in accordance with Table 3.

(E) A pilot-in-command intending to operate an aircraft without an operable transponder in transponder mandatory airspace that is within controlled airspace must obtain specific authorisation from the ATC unit having jurisdiction over the relevant airspace as part of the ATC clearance to enter that airspace.