JO 7110.65 5-2-8

Special use Mode 3/A codes are reserved for certain pressure suit flights and aircraft operations above FL 600 in accordance with FAA Order JO 7610.4, Sensitive Procedures and Requirements for Special Operations, Appendix 4, Document 2.

Ensure that these flights remain on one of the special use codes if filed in the flight plan, except:

When unforeseen events cause more than one aircraft to be in the same or adjacent ARTCC's airspace at the same time on the same special use discrete code, if necessary, you may request the pilot to make a code change, squawk standby, or stop squawk as appropriate. NOTE-

Current FAA automation systems track multiple targets on the same beacon code with much greater reliability than their predecessors, and a code change may not be necessary for such flights.

The beacon code is often preset on the ground for such flights and is used throughout the flight profile, including operations below FL 600. Due to equipment inaccessibility, the flight crew may not be able to accept transponder changes identified in this subparagraph.

In case of emergency, Code 7700 can still be activated. Instead of displaying “7700” in the data block, ERAM will display “EMRG,” and STARS/MEARTS will display “EM.”

REFERENCE-

FAA Order JO 7110.65, Para 5-3-3 , Beacon/ADS-B Identification Methods.