Publication: Magyar Közlöny
Issue: MK-2007-70 (Year: 2007, Number: 70)
Era: 2004-2010
Section: Melléklet a 2007. évi XLVI. törvényhez
Paragraph Index: 4617

b) the Mode A/C/S all-call of 3.1.2.1.5.1.1. This lockout condition shall persist for an interval TD (3.1.2.10.3.9) after the last receipt of the command. Non-selective lockout shall not prevent acceptance of a Mode S-only all-call interrogation containing PR codes 8 to 12. Note 2.— Non-selective lockout does not affect the response of the transponder to Mode S-only all-call interrogations containing II not equal to 0. 3.1.2.6.10 BASIC DATA PROTOCOLS 3.1.2.6.10.1 Flight status protocol. Flight status shall be reported in the FS field (3.1.2.6.5.1). 3.1.2.6.10.1.1 Alert. An alert condition shall be reported in the FS field if the Mode A identity code transmitted in Mode A replies and in downlink formats DF equals 5 and DF equals 21 are changed by the pilot. 3.1.2.6.10.1.1.1 Permanent alert condition. The alert condition shall be maintained if the Mode A identity code is changed to 7500, 7600 or 7700. 3.1.2.6.10.1.1.2 Temporary alert condition. The alert condition shall be temporary and shall cancel itself after TC seconds if the Mode A identity code is changed to a value other than those listed in 3.1.2.6.10.1.1.1. Note.— The value of TC is given in 3.1.2.10.3.9. 3.1.2.6.10.1.1.3 Termination of the permanent alert condition. The permanent alert condition shall be terminated and replaced by a temporary alert condition when the Mode A identity code is set to a value other than 7500, 7600 or 7700. 3.1.2.6.10.1.2 Ground report. The on-the-ground status of the aircraft shall be reported in the FS field and the VS field (3.1.2.8.2.1) and the CA field (3.1.2.8.1.1). If a means for automatically indicating the on-the-ground condition (e.g. a weight on wheels or strut switch) is available at the transponder data interface, it shall be used as the basis for the reporting of vertical status. If a means for automatically indicating the on-the-ground condition is not available at the transponder data interface (3.1.2.10.5.1.3), the FS and VS codes shall indicate that the aircraft is airborne and the CA field shall indicate that the aircraft is either airborne or on the ground (CA = 6). 3.1.2.6.10.1.3 Special position identification (SPI). An equivalent of the SPI pulse shall be transmitted by Mode S transponders in the FS field and the surveillance status subfield (SSS) when manually activated. This pulse shall be transmitted for TI seconds after initiation (3.1.1.6.3, 3.1.1.7.13 and 3.1.2.8.6.3.1.1). Note.— The value of TI is given in 3.1.2.10.3.9. 3.1.2.6.10.2 Capability reporting protocol Note.— Aircraft capability is reported in special fields as defined in the following paragraphs. 3.1.2.6.10.2.1 Capability report. The 3-bit CA field, contained in the all-call reply, DF equals 11, shall report the basic capability of the Mode S transponder as described in 3.1.2.5.2.2.1. 3.1.2.6.10.2.2 Data link capability report. The data link capability report shall provide the interrogator with a description of the data link capability of the Mode S installation. The report shall be obtained by a ground-initiated Comm-B reply in response to an interrogation containing RR equals 17 and DI is not equal to 7 or DI equals 7 and RRS equals 0 (3.1.2.6.11.2). The definition of this register is described in 5.2.9.2 of Volume III to Annex 10. 3.1.2.6.10.2.2.1 Subfields in MB for data link capability report. The subfields within the MB field of all data link capability reports shall be: (3.1.2.6.11.2.1) BDS1 A value of 1 shall be inserted in this 4-bit (33-36) subfield as a first part of Comm-B data selector (BDS) code. 2007/70/II. szám Annex 10 — Aeronautical Telecommunications Volume IV 28/11/02 3-38 BDS2 A value of 0 shall be inserted in this 4-bit (37-40) subfield as a second part of Comm-B data selector (BDS) code. SCS This 1-bit (66) squitter capability subfield shall report the capability of the transponder to transmit extended squitter position reports. It shall be set to 1 if BDS registers 05 and 06 {HEX} have been updated within the last ten plus or minus one seconds. Otherwise, it shall be set to 0. Note.— BDS registers 05 and 06 {HEX} are used for the extended squitter airborne and surface position reports, respectively. SIC This 1-bit (67) surveillance identifier capability subfield shall report the capability of the transponder to support the surveillance identifier (SI) codes. 3.1.2.6.10.2.2.2 Updating of the data link capability report. The transponder shall, at intervals not exceeding four seconds, compare the current data link capability status with that last reported and shall, if a difference is noted, initiate a revised data link capability report by Comm-B broadcast (3.1.2.6.11.4) for BDS1 = 1 (33-36) and BDS 2 = 0 (37-40). The transponder shall initiate, generate and transmit the revised capability report even if the aircraft data link capability is degraded or lost. The transponder shall set the BDS code for the data link capability report. Note.— The setting of the BDS code by the transponder ensures that a broadcast change of capability report will contain the BDS code for all cases of data link failure (e.g. the loss of the transponder data link interface). 3.1.2.6.10.3 Validation of declared on-the-ground status Note.— For aircraft with an automatic means of determining vertical status, the CA field reports whether the aircraft is airborne or on the ground. ACAS II acquires aircraft using the short or extended squitter, both of which contain the CA field. If an aircraft reports on-the-ground status, that aircraft will not be interrogated by ACAS II in order to reduce unnecessary interrogation activity. If the aircraft is equipped to report extended squitter messages, the function that formats these messages may have information available to validate that an aircraft reporting “on-the-ground” is actually airborne. 3.1.2.6.10.3.1 Aircraft with an automatic means for determining the on-the-ground condition that are equipped to format extended squitter messages shall perform the following validation check: If the automatically determined air/ground status is not available or is “airborne”, no validation shall be performed. If the automatically determined air/ground status is available and “on-the-ground” condition is being reported, the air/ground status shall be overridden and changed to “airborne” if the conditions given for the vehicle category in Table 3-6 are satisfied. Note.— While this test is only required for aircraft that are equipped to format extended squitter messages, this feature is desirable for all aircraft. 3.1.2.6.11 STANDARD LENGTH COMMUNICATIONS PROTOCOLS Note 1.— The two types of standard length communications protocols are Comm-A and Comm-B; messages using these protocols are transferred under the control of the interrogator. Comm-A messages are sent directly to the transponder and are completed within one transaction. A Comm-B message is used to transfer information from air to ground and can be initiated either by the interrogator or the transponder. In the case of ground-initiated Comm-B transfers, the interrogator requests data to be read out from the transponder, which delivers the message in the same transaction. In the case of airinitiated Comm-B transfers, the transponder announces the intention to transmit a message; in a subsequent transaction an interrogator will extract the message. Note 2.— In a non-selective air-initiated Comm-B protocol all transactions necessary can be controlled by any interrogator. Note 3.— In some areas of overlapping interrogator coverage there may be no means for coordinating interrogator activities via ground communications. Air-initiated Comm-B communications protocols require more than one 2007/70/II. szám Chapter 3 Annex 10 — Aeronautical Telecommunications 3-39 28/11/02 transaction for completion. Provision is made to ensure that a Comm-B message is closed out only by the interrogator that actually transferred the message. This can be accomplished through the use of the multisite Comm-B communications protocols or through the use of the enhanced Comm-B communications protocols. Note 4.— The multisite and the non-selective communications protocols cannot be used simultaneously in a region of overlapping interrogator coverage unless the interrogators coordinate their communications activities via ground communications. Note 5.— The multisite communications protocol is independent of the multisite lockout protocol. That is, the multisite communications protocol may be used with the non-selective lockout protocol and vice versa. The choice of lockout and communications protocols to be used depends upon the network management technique being used. Note 6.— The broadcast Comm-B protocol can be used to make a message available to all active interrogators. 3.1.2.6.11.1 Comm-A. The interrogator shall deliver a Comm-A message in the MA field of an interrogation UF = 20 or 21. 3.1.2.6.11.1.1 Comm-A technical acknowledgement. Acceptance of a Comm-A interrogation shall be automatically technically acknowledged by the transponder, by the transmission of the requested reply (3.1.2.10.5.2.2.1). Note.— The receipt of a reply from the transponder according to the rules of 3.1.2.4.1.2.3 d) and 3.1.2.4.1.3.2.2.2 is the acknowledgement to the interrogator that the message has been received and stored by the transponder. If either uplink or downlink fail, this reply will be missing and the interrogator will normally send the message again. In the case of downlink failure the transponder may receive the message more than once. 3.1.2.6.11.1.2 Comm-A broadcast. If a Comm-A broadcast interrogation is accepted (3.1.2.4.1.2.3.1.3) information transfer shall be handled according to 3.1.2.10.5.2.1.1 but other transponder functions shall not be affected and a reply shall not be transmitted. Note 1.— There is no technical acknowledgement to a Comm-A broadcast message. Note 2.— Since the transponder does not process the control fields of a Comm-A broadcast interrogation, the 27 bits following the UF field are also available for user data. 3.1.2.6.11.2 Ground-initiated Comm-B 3.1.2.6.11.2.1 Comm-B data selector, BDS. The 8-bit BDS code shall determine the register whose contents shall be transferred in the MB field of the Comm-B reply. It shall be expressed in two groups of 4 bits each, BDS1 (most significant 4 bits) and BDS2 (least significant 4 bits). Note 1.— The transponder register allocation is specified in Annex 10, Volume III, Part I, Chapter 5, Table 5-24. Table 3-6. Validation of on-the-ground status Determination of airborne status A/V category Ground Speed Airspeed Radio Altitude No information No change to on-the-ground status Weight < 15 500 lbs (7 031 kg) No change to on-the-ground status Weight >15 500 lbs (7 031 kg) >100 knots or >100 knots or >50 feet High performance (>5 g acceleration and >400 knots) >100 knots or >100 knots or >50 feet Rotorcraft No change to on-the-ground status 2007/70/II. szám Annex 10 — Aeronautical Telecommunications Volume IV 28/11/02 3-40 Note 2.— The only registers defined in this section are those for aircraft identification (3.1.2.9.1.2), datalink capability reporting (3.1.2.6.10.2.2), extended squitter (3.1.2.8.6.2) and downlink aircraft parameters (DAPs) (3.1.2.10.5.2.3). 3.1.2.6.11.2.2 BDS1 code. The BDS1 code shall be as defined in the RR field of a surveillance or Comm-A interrogation. 3.1.2.6.11.2.3 BDS2 code. The BDS2 code shall be as defined in the RRS subfield of the SD field (3.1.2.6.1.4.1) when DI = 7. If no BDS2 code is specified (i.e. DI is not equal to 7) it shall signify that BDS2 = 0. 3.1.2.6.11.2.4 Protocol. On receipt of such a request, the MB field of the reply shall contain the contents of the requested ground-initiated Comm-B register. 3.1.2.6.11.3 Air-initiated Comm-B 3.1.2.6.11.3.1 General protocol. The transponder shall announce the presence of an air-initiated Comm-B message with the insertion of code 1 in the DR field. To extract an air-initiated Comm-B message, the interrogator shall transmit a request for a Comm-B message reply in a subsequent interrogation with RR equal to 16 and, if DI equals 7, RRS must be equal to 0 (3.1.2.6.11.3.2.1 and 3.1.2.6.11.3.3.1). Receipt of this request code shall cause the transponder to transmit the air-initiated Comm-B message. If a command to transmit an air-initiated Comm-B message is received while no message is waiting to be transmitted, the reply shall contain all ZEROs in the MB field. The reply that delivers the message shall continue to contain code 1 in the DR field. After a Comm-B closeout has been accomplished, the message shall be cancelled and the DR code belonging to this message immediately removed. If another air-initiated Comm-B message is waiting to be transmitted, the transponder shall set the DR code to 1, so that the reply contains the announcement of this next message. Note.— The announcement and cancellation protocol ensures that an air-initiated message will not be lost due to uplink or downlink failures that occur during the delivery process. 3.1.2.6.11.3.2 Additional protocol for multisite air-initiated Comm-B Note.— The announcement of an air-initiated Comm-B message waiting to be delivered may be accompanied by a multisite reservation status report in the UM field (3.1.2.6.5.3.2). Recommendation.— An interrogator should not attempt to extract a message if it has determined that it is not the reserved site. 3.1.2.6.11.3.2.1 Message transfer. An interrogator shall request a Comm-B reservation and extract an air-initiated Comm-B message by transmitting a surveillance or Comm-A interrogation UF equals 4, 5, 20 or 21 containing: RR = 16 DI = 1 IIS = assigned interrogator identifier MBS = 1 (Comm-B reservation request) Note.— A Comm-B multisite reservation request is normally accompanied by a Comm-B reservation status request (RSS = 1). This causes the interrogator identifier of the reserved site to be inserted in the UM field of the reply. 3.1.2.6.11.3.2.1.1 Protocol procedure in response to this interrogation shall depend upon the state of the B-timer which indicates if a Comm-B reservation is active. This timer shall run for TR seconds. Note 1.— The value of TR is given in 3.1.2.10.3.9.

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