ICAO Doc 4444
Appendix 2
ITEM 10: EQUIPMENT AND CAPABILITIES
Surveillance equipment and capabilities

• INSERT N if no surveillance equipment for the route to be flown is carried, or the equipment is unserviceable,

OR

• INSERT one or more of the following descriptors, to a maximum of 20 characters, to describe the serviceable surveillance equipment and/or capabilities on board:

SSR Modes A and C
A Transponder — Mode A (4 digits — 4096 codes)
C Transponder — Mode A (4 digits — 4096 codes) and Mode C

SSR Mode S
E Transponder — Mode S, including aircraft identification, pressure-altitude and extended squitter (ADS-B) capability
H Transponder — Mode S, including aircraft identification, pressure-altitude and enhanced surveillance capability
I Transponder — Mode S, including aircraft identification, but no pressure-altitude capability
L Transponder — Mode S, including aircraft identification, pressure-altitude, extended squitter (ADS-B) and enhanced surveillance capability
P Transponder — Mode S, including pressure-altitude, but no aircraft identification capability
S Transponder — Mode S, including both pressure altitude and aircraft identification capability
X Transponder — Mode S with neither aircraft identification nor pressure-altitude capability

Note.— Enhanced surveillance capability is the ability of the aircraft to down-link aircraft derived data via a Mode S transponder.

• Mode A equipment transmits an identifying code only.
• Mode C equipment enables the ATCO to see the aircraft altitude or flight level automatically