Part A: Secondary surveillance radar transponder capabilities referred to in Article 4(3), point (a) of Article 5(5), Article 7(2) and Article 8(1) and (3)

1. The minimum capability for the secondary surveillance transponder shall be Mode S Level 2 meeting the performance and functionality criteria of Annex 10 to the Chicago Convention, Volume IV, Third Edition including all amendments up to No 77.

2. Each implemented transponder register shall be compliant with the corresponding section of ICAO document 9871 (2nd edition).

3. The following data items shall be made available to the transponder and be transmitted by the transponder via the Mode S protocol and in accordance with the formats specified in ICAO document 9871 (2nd edition):

(a)  24-bit ICAO aircraft address;

(b)  Mode A code;

(c)  pressure altitude;

(d)  flight status (on the ground or airborne);

(e)  data link capability report;

  • airborne collision avoidance system (ACAS) capability,
  • Mode S specific services capability,
  • aircraft identification capability,
  • squitter capability,
  • surveillance identifier capability,
  • common usage Ground Initiated Comms.-B (GICB) capability report (indication of change),

  • Mode S subnetwork version number;

(f)  common usage GICB capability report;

(g)  aircraft identification;

(h)  special position indication (SPI);

(i)  emergency status (general emergency, no communications, unlawful interference) including the use of specific Mode A codes to indicate different emergency states;

(j)  ACAS active resolution advisories when the aircraft is equipped with Traffic alert and collision avoidance system II (TCAS II).

4. Other data items may be made available to the transponder.

5. The data items referred to in point 4 shall only be transmitted by the transponder via the Mode S protocol. The aircraft and equipment certification process shall cover the transmission of those data items.

6. Provision repealed before document was retained.