Reference (F) Mode S FRD.pdf

CHIEF OF NAVAL OPERATIONS

Functional Requirements Document

For

MODE SELECT

[FRD For Mode S]

Revision A

17 May 2006

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

ii

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FUNCTIONAL REQUIREMENTS DOCUMENT For MODE SELECT (Mode S)

(FRD For Mode S)

PROGRAM TITLE:

PREPARED BY:

BASEliNE FRD DATE:

FRD Revision A:

COMMUNICA TIONSINA VIGA TION/SURVEILLANCE/

AIR TRAFFIC MANAGEMENT (CNS/ATM)

Mr, Berk C, Hoover, PMA209 CNSIATM IPT Lead

14July 2003 17 May 2006 regoryA. Sllvemagel,"CAPTAIN, U.S. Navy Air Combat Electronics Program Manager (PMA209) Naval Air Systems Command

6 A~ Ob Date Released

{It?

, C.E. Smith, RDML, U.S Navy

Naval Air Systems Command Acting Assistant Commander for Acquisition (AIR-1.0)

/;{J'fJ7VO 7 Date Reviewed

Bruce W. Clingan, RADM, U.S. Navy Chief of Naval Operations Director, Air Warfare (N88)

Date Approved

III

:S",', , ,',',',',, , , , , , , " ,, , , , , . , , , iv

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v

CHANGE SUMMARY PAGE

This change summary page is provided to maintain a record of change to the last issue of the FRD. Upon receipt of a change or revision, the holder of the FRD should incorporate the change(s)/revision(s) into the original and make an appropriate entry on the Record of Change listing below:

RECORD OF CHANGE

CHANGE

NUMBER DATE CHANGE ENTERED BY

Initial Issue

Revision A

14 July 2003

17 May 2006

Document Baseline (under formal PMA209 Configuration

Control)

Page iii, Added signature page.

Page vii, Executive Summary – Improved readability and deleted superfluous information.

Page 1, Para. 1.1 Deleted mention of 25 foot requirement as it is mentioned later in the document.

Page 1, Para. 1.2 Corrected EUROCONTROL acronym, added requirement for transponders to meet AIMS 97-1000, and enhanced clarity.

Pages 1-2, Para. 1.3 Split paragraph into paragraphs 1.3. and

1.4, revised wording and added sentence concerning latest

European Mode S compliance mandate. Deleted information about NATO and Mode S.

Page 2, Para. 1.3.1, Added paragraph addressing state transport aircraft requirements.

Page 2, Para. 1.3.2, Added paragraph addressing state tactical aircraft requirements.

Page 4, Para. 2.1 Updated the documents, deleted RTCA DO-

181C, and modified the order of precedence.

Page 4, Para. 2.2 Updated the DOD reference.

Page 4, Para. 2.3 Modified the reference for NATO STANAG, Part I and NATMC Concept of Employment of Employment for

Mode S

Page 5, Para. 2.4 Updated EUROCONTROL references by adding Mode S Transition Arrangements for State Aircraft and deleted Mode S CONOPS.

Page 5, Para. 2.5 Updated ICAO documents, adding ICAO

Annex 10, Volume III and deleting ICAO documents 7030/4 and 9688-AN/952.

Page 6. Para. 3.1, added requirements to support Surveillance

Identifier Codes, requirements for transponder AIMS

Certification and reworded other requirements.

Page 6, Para. 3.1.1 Added paragraph outlining Navy requirements by platform type to integrate Elementary and

Enhanced Surveillance.

Page 7, renumbered former paragraph 3.1.1 as 3.1.2 and this impacted the following paragraphs as well. Revised Level 5

Definition. Added ICAO Reference.

Page 7, Renumbered paragraph 3.1.1.1 as 3.1.2.1.

Page 7, Renumbered Table 3.1.1.1-1 as Table 1 and added several undefined formats to the Not Required Column.

Page 8, Revised the material originally in paragraph 3.1.1.2 and placed the new material in paragraphs 3.1.3, and 3.1.3.1 through

3.1.3.3.

Page 8, Added paragraph 3.1.3.1 Elementary Surveillance.

Page 8, Renumbered Table 3.1.1.2-1 as Table 2. and the title from “Elementary Surveillance Data Parameters” to

“Elementary Surveillance Downlink Format”

Page 8, Added Table 3 for Elementary Surveillance Data

Mr. Berk C. Hoover

CNS/ATM IPTL

Mark Annee CNS/ATM

Lead Surveillance

Engineer vi

Parameters.

Page 9, Revised enhanced surveillance material from paragraph 3.1.1.2 and created new paragraph 3.1.3.2.

Page 9, Revised Table number from 3.1.1.2-2 to Table 4.

Added alternative (TAS) for Track Angle Rate and Elementary

Surveillance Functionality (BDS 1/0, etc.). Changed "Selected

Altitude" to "Mode Control Panel/Flight Control Unit

(MCP/FCU) Selected Altitude"

Page 9, Created paragraph 3.1.3.3 to address BDS register update rates.

Page 9, Revised Table number from 3.1.1.2-3 to Table 5, and revised times for minimum update rates for Common usage

GICB capability report, track and turn report and heading and speed report and added note 3.

Page 10, Renumbered para. 3.1.1.3 to 3.1.4. Mode S Squitter, revised wording and added "should" to support growth to

Extended Squitter (ADS-B) and added subparagraphs a. and b.

discussing Acquisition Squitter and Extended Squitter.

Page10, Renumbered Para. 3.1.2 as 3.1.5, added Comm-A and

Comm-U Processing requirements for TCAS-equipped aircraft and updated reference.

Page10, Renumbered Para. 3.1.2.1 to Para. 3.1.5.1 and updated reference.

Page 10 (14 July 03 Version), Deleted Para. 3.1.3, Military

Specific Characteristics.

Page 10 (14 July 03 Version) , Deleted paragraph 3.1.3.1, Receiver Sensitivity.

Page 10, Renumbered Para. 3.1.3.2 as para. 3.1.6 and updated reference.

Page 11, Renumbered Para. 3.1.3.3 as Paragraph 3.1.7, re-titled heading to "Transponder Controls", and revised the paragraph.

Pages 11, Renumbered and renamed Table 3.1.3.3-1 as Table 6, and made the following changes:

1. Added requirement to operate in diversity at all times except for maintenance purposes.

2. Removed controls and indicators for most non-Mode S

MK XII functions in Table 6.

3. Deleted Acquisition Squitter ON/OFF capability.

4. Revised Mode S Aircraft ID.

5. Revised Mode S Max Airspeed to XXXX

6. Revised Mode S Extended Squitter, adding "and may be implemented at a later date."

7. Added ON/OFF for Mode S Enhanced Surveillance. In the OFF position, the transponder will operate in the

Elementary Surveillance Mode only.

Page 13 (14 July 03 Version), Deleted Table 3.1.3.3-2, Controls for Transponders with TCAS.

Page 11, Renumbered paragraph 3.1.4 to 3.1.8 .

Page 12, Added Para. 3.2, 3.2.1-3.2.3 concerning 24-bit Default and Selectable Addresses.

Page 13, Appendix A Updated acronyms.

This document is under Configuration Management Control at NAVAIR, PMA209 Patuxent River, MD. Comments and suggested changes and updates to the document should be addressed to the following NAVAIR, PMA209, Configuration Management Control Point:

Send to: NAVAIRSYSCOM

Attn.: PMA209 CNS/ATM Program Office

47123 Buse Rd.

Bldg. 2272, Suite 351

Patuxent River, MD 20670

Fax No: (301) 757-6459 vii

EXECUTIVE SUMMARY

This document establishes the minimum functional requirements for Navy, Marine Corps, and

Coast Guard aircraft to conform to civil airspace mandates for Mode S surveillance. The Mode

S Beacon System is a combined data link and Secondary Surveillance Radar (SSR) system that was standardized in 1985 by the International Civil Aviation Organization (ICAO) in the

International Standards and Recommended Practices (SARPS) publication, ICAO Annex 10.

Mode S is capable of supporting Air Traffic Control (ATC) automation in today’s dense traffic environments with more capability than the current aging Air Traffic Control Radar Beacon

System (ATCRBS) provides. It is also backward compatible with ATCRBS. Mode S transponder function is a Communication, Navigation, Surveillance / Air Traffic Management

(CNS/ATM) Naval program requirement.

In the National Air Space, the Federal Aviation Administration (FAA) is transitioning to Mode S by installing new Mode S equipment at ATCRBS ground sites and has made both systems concurrent in operation. Mode S equipment is also gradually being installed into new production aircraft. Because both SSR ground beacon systems are in simultaneous operation, interrogated aircraft replies are dependent upon the type of transponder installed in the aircraft. The FAA is expected to migrate to Mode S operation in the future, as more aircraft become Mode S capable.

PMA209 is designated as the Navy Lead Program Office to coordinate Communication, Navigation, Surveillance / Air Traffic Management (CNS/ATM) efforts as chartered via Deputy

Chief of Naval Operations for Air Warfare (N78) Letter (CNO Ser 7U660859 dated 14 October

1997). In accordance with this tasking, PMA209 has developed this Mode Select FRD for

Naval, Marine Corps, and Coast Guard Aviation.

viii

TABLE OF CONTENTS

1.0 INTRODUCTION

1.1 PURPOSE

1.2 SCOPE

1.3 BACKGROUND

1.3.1 STATE TRANSPORT AIRCRAFT

1.3.2 STATE TACTICAL AIRCRAFT

1.4 EUROCONTROL MODE S GEOGRAPHIC AREA AND AIRSPACE

2.0 REFERENCE DOCUMENTS

2.1 DOCUMENT ORDER OF PRECEDENCE FOR MILITARY MODE S

REQUIREMENTS

2.2 DOD DOCUMENTS

2.3 NATO DOCUMENTS

2.4 EUROCONTROL DOCUMENTS

2.5 ICAO DOCUMENTS

2.6 RTCA DOCUMENTS

3.0 REQUIREMENTS

3.1 GENERAL REQUIREMENTS

3.1.1 INTEGRATION OF MODE S IN AIRCRAFT

3.1.2 AIRBORNE TRANSPONDER MODE S CAPABILITY AND FORMATS

3.1.3 ELEMENTARY AND ENHANCED SURVEILLANCE

3.1.4 MODE S SQUITTERS

3.1.5 MODE S TRANSPONDER TRAFFIC ALERT AND COLLISION AVOIDANCE

SYSTEM (TCAS II) CAPABILITY

3.1.6 EMERGENCY

3.1.7 TRANSPONDER CONTROLS

3.1.8 ALTITUDE CODE

3.2 NAVY MODE S 24-BIT ADDRESS

3.2.1 MODE S 24-BIT DEFAULT ADDRESS

3.2.2 MODE S 24-BIT SELECTABLE ADDRESS

3.2.3 POWER INTERRUPTIONS AND 24-BIT ADDRESS

APPENDIX A. ACRONYMS AND ABBREVIATIONS

LIST OF FIGURES

FIGURE 1-1. APPLICABLE AREA OF IIMSES

FIGURE 1-2. ILLUSTRATIVE CROSS SECTION OF MODE S AIRSPACE

ix

LIST OF TABLES

TABLE 1. MODE S FORMATS

TABLE 2. ELEMENTARY SURVEILLANCE DOWNLINK FORMAT

TABLE 3. ELEMENTARY SURVEILLANCE DATA PARAMETERS

TABLE 4. ENHANCED SURVEILLANCE DATA PARAMETERS

TABLE 5. BDS REGISTER UPDATE RATES

TABLE 6. CONTROLS FOR MODE S TRANSPONDERS

1.0 INTRODUCTION

1.1 PURPOSE

This document establishes the minimum functional requirements for Navy, Marine Corps, and

Coast Guard aircraft to conform to civil mandates for Mode S Elementary Surveillance (ELS) and Enhanced Surveillance (EHS). To meet these requirements, aircraft must be equipped with a

Mode S Level 2 transponder with the capability for Comm-B data link communications

(Standard Length Communications Protocol), antennas, an altitude source, an Air Data Link

Processor (ADLP) or equivalent, and an appropriate control unit (Remote Control Unit or 1553 bus control). Aircraft that are designed, integrated, and tested to meet the functional requirements specified herein will be compliant with international standards for Mode S operation.

1.2 SCOPE

This Functional Requirements Document (FRD) specifically addresses the integration requirements for Navy, Marine Corps, and Coast Guard aircraft carrying Mode S transponders to comply with international civil Mode S standards in order to retain access to global airspace.

Specific box-level transponder requirements are covered by AIMS 97-1000. The requirements stated in this document may or may not quote verbatim the European Organization for the Safety of Air Navigation (EUROCONTROL) references. The verbiage has been modified as necessary to facilitate Navy, Marine Corps, and Coast Guard needs and this document.

1.3 BACKGROUND

Mode S Operation in European Air Space for State (military) aircraft

The European Organization for the Safety of Air Navigation issued a directive on 22 August

2005 for the “Harmonisation of the Transition Arrangements for State aircraft”. This directive details the process and procedures for the managing of the Mode S compliance status and the exemption granted to State aircraft. The directive for State aircraft allows exemptions for Mode

S requirements in Europe to change from 2007 to 2009. The only exemptions allowed beyond the March 2009 deadline are for "aircraft that will be out of service by 31 December 2009 and aircraft used for flight testing, for delivery, or for transit into and out of maintenance bases".

The final date for compliance for the carriage and operation of Mode S Elementary

Surveillance (ELS) and Enhanced Surveillance (EHS) airborne equipment is 31 March

2009.

The integration of Mode S Level 2 into Navy platforms is divided into two variations of functionality, Elementary Surveillance and Enhanced Surveillance. It is beneficial to air traffic control to incorporate EHS functionality to the extent practicable on all naval aircraft and to populate EHS data parameters to the extent permitted by existing aircraft sensors. The Mode S requirement is broken down into two types of aircraft.

1.3.1 STATE TRANSPORT AIRCRAFT

As stated by EUROCONTROL in their "Mode S Harmonisation of the Transition Arrangements for State Aircraft", Edition 1.1, “The carriage and operation of Mode S Enhanced Surveillance functionality applies to transport type State aircraft with a maximum take-off mass in excess of

5700kg or a maximum true cruising airspeed in excess of 250kts and a “full” Downlink of

Aircraft Parameters capability, conducting Instrument Flying Rules (IFR) flights as General Air

Traffic in Mode S Enhanced designated airspace for more than 30 hours per year per airframe.”

The “full” set of Enhanced Surveillance Data Parameters are shown in Table 4 herein.

1.3.2 STATE TACTICAL AIRCRAFT

The carriage and operation of Mode S Elementary Surveillance functionality applies to Rotary-wing aircraft, training aircraft, unmanned air vehicles, and fighter aircraft that fly IFR and Visual

Flight Rules flights in Mode S designated airspace.

1.4 EUROCONTROL Mode S Geographic Area and Airspace

The EUROCONTROL Concept of Operations (CONOPS) for Initial Implementation of Mode S

Enhanced Surveillance (IIMSES) in Europe takes account of the geographic area defined as the

Core Area. Figure 1-1 illustrates the core area of Mode S operations.

FIGURE 1-1. APPLICABLE AREA OF IIMSES

The CONOPS also takes into account the lateral aspects of the airspace applicable to the introduction of Enhanced Surveillance as defined in the IIMSES Strategy. This consists of at least duplicated Mode S radar coverage at and above a flight level of 10,000 feet (FL100). Figure

1-2 depicts an illustrative cross section of the IIMSES airspace.

FIGURE 1-2. ILLUSTRATIVE CROSS SECTION OF MODE S AIRSPACE

Terminal Area Terminal Area

2.0 REFERENCE DOCUMENTS

2.1 DOCUMENT ORDER OF PRECEDENCE FOR MILITARY MODE S

REQUIREMENTS

Requirements within this FRD are primarily based on airborne transponder Mode S functionality and interoperability guideline requirements. These requirements are identified in the DoD AIMS

97-1000, 18 March 1998, STANAG 4193 Parts I and IV, and ICAO Annex 10 Vol. III and IV.

Air Traffic Control Radar Beacon System (ATCRBS), Identification Friend or Foe (IFF), Mark

XII System (AIMS) equipment will incorporate Mode S capability to the extent required to perform the intended functions. Unless otherwise specified in this document, a military Mode S integration shall meet the applicable requirements of ICAO Annex 10 Vol. III and IV with exceptions that are detailed in STANAG 4193 Part IV. In case of a conflict, the order of precedence shall be this FRD, STANAG 4193 part IV, ICAO Annex 10, and then AIMS 97-

1000.

2.2 DOD DOCUMENTS

DoD AIMS 97-1000, Performance/Design and Qualification

18 March 1998 Requirements Technical Standard for the

ATCRBS/IFF/MARK XII Electronic Identification

System and Military Mode S

2.3 NATO DOCUMENTS

STANAG 4193, Part IV, Technical Characteristics of IFF Mk XA and Mk

12 April 1999 XII Interrogators and Transponders-Technical

Characteristics of Mode S in Military Interrogators and Transponders (NATO UNCLASSIFIED)

2.4 EUROCONTROL DOCUMENTS

Mode S Harmonisation of the Process and Procedures for the Managing of the

Transition Arrangements for Mode S Compliance Status and the Exemption

State Aircraft Edition 1.1 Granted to State Aircraft

22 August 2005

2.5 ICAO DOCUMENTS

(a). ICAO Annex 10, to the Standards and Recommended Practices (SARPS)

Convention on Civil Aviation, for Mode S (Digital Communications Systems)

Vol. III, Communication Systems st edition, Amendment 78

27 November 2003

(b). ICAO Annex 10, to the Standards and Recommended Practices (SARPS)

Convention on Civil Aviation, for Mode S

Vol. IV, Surveillance Radar and

Collision Avoidance Systems rd edition, Amendment 77

28 November 2002

2.6 RTCA DOCUMENTS

(a). RTCA/DO-185A, Minimum Operation Performance Standards for

16 December 1997 Traffic Alert and Collision Avoidance System II

(TCAS II) Airborne Equipment

3.0 REQUIREMENTS

3.1 GENERAL REQUIREMENTS

The integration of a military Mode S transponder shall provide the operational capabilities of

Mode S and shall not degrade Mark XII capabilities (Modes 1, 2, 3/A, C and 4) . The Mode S

Level 2 transponder must comply with the provisions of ICAO Annex 10, Standards and

Recommended Practices (SARPs), Amendment 77 to include supporting Surveillance Identifier codes. The Mode S transponder shall have an AIMS certification prior to platform Mode S certification.

3.1.1 INTEGRATION OF MODE S IN AIRCRAFT

All aircraft operating in Mode S designated airspace (with the exception of rotary-wing aircraft, training aircraft, and fighter aircraft) with a maximum take-off mass in excess of 5700kg or a maximum true cruising airspeed in excess of 250kts shall integrate Mode S Level 2 Enhanced

Surveillance functionality. Mode S Enhanced Surveillance shall include full Downlink of

Aircraft Parameters capability as specified in Table 4.

All aircraft operating in Mode S designated airspace not required to integrate Mode S Level 2

EHS functionality shall integrate Mode S Level 2 Elementary Surveillance. As an objective, these aircraft should also integrate Mode S Enhanced Surveillance parameters to the extent of the existing sensors and integrations available onboard the aircraft.

3.1.2 AIRBORNE TRANSPONDER MODE S CAPABILITY AND FORMATS

Mode S is an ATC system that can respond to selective interrogations and provide air-to-air and air-to-ground data link of Aircraft Identification (ID), state, and intent information. It is stipulated in ICAO SARPS Annex 10, that Mode S transponders shall conform to one of five

Levels of capability:

Level 1 This is the basic transponder. Level 1 permits surveillance based on Mode 3/A

& C as well as Mode S. With a Mode S aircraft address, it comprises the minimum features for compatible operation with Mode S interrogators. It has no data link capability and will not be used by international air traffic control in EUROCONTROL. It is not permitted for use in the ICAO EUR.

Level 2 Level 2 has the same capabilities as Level 1 but allows standard data link communications from ground-to-air and air-to-ground. It also includes automatic aircraft identification reporting. This is the minimum level permitted for international air traffic control in the ICAO EUR.

Level 3 Level 3 has the same capabilities as Level 2, but allows extended data link communications from the ground to the aircraft.

Level 4 Level 4 has the same capabilities as Level 3, but allows extended data link communications from the aircraft to the ground.

Level 5 Level 5 has the same capabilities as Level 4, but allows for Comm-B and extended length data link communications with multiple interrogators without requiring the use of multi-site reservations. This level of transponder has the highest data link capability.

Mode S, Level 2 integration shall be the U.S. Navy minimum Mode S requirement. Levels 3, 4, and 5 are outside the scope of this FRD.

Ref: ICAO Annex 10, paragraph 2.1.5.1, Vol. IV, amended.

3.1.2.1 MODE S FORMATS

Mode S provides for twenty-five interrogation/reply format pairs, not all of which are currently defined. Each format pair consists of an interrogation Uplink Format (UF) and an associated transponder reply Downlink Format (DF). Each Mode S transponder shall be capable of operating with the formats listed as “Required” in Table 1.

TABLE 1. MODE S FORMATS

UF/DF Message Format Required Future

Growth

Not

Required

0 Short (56-bit), Air to Air Surveillance (TCAS)

X

1 – 3 Undefined X

4 Short (56-bit), Surveillance Altitude X

5 Short (56-bit), Surveillance Identity X

6 – 10 Undefined X

11 Mode S Only All-Call X

12 – 15 Undefined X

16 Long (112-bit), Air to Air Surveillance

(TCAS)

X

17, 18 Extended Squitter (112-bit Standard ADS-B /

DF Only)

X

19 Extended Squitter (112-bit Military Format

ADS-B / DF Only)

X

20 Long (112-bit), Comm-A/B Altitude X

21 Long (112-bit), Comm-A/B Identity X

22, 23 Undefined X

24 Long (112-bit), Comm-C/D, Extended Length

Message

X

Notes:

UF/DF 0 and 16 are used for TCAS operation. All transponder integrations are required to respond to UF 0 interrogations.

Transponder integrated with TCAS processors shall respond to UF0 and UF16 interrogations.

3.1.3 ELEMENTARY AND ENHANCED SURVEILLANCE

3.1.3.1 ELEMENTARY SURVEILLANCE

The Mode S Downlink Formats required to support Elementary Surveillance are provided in

Table 2. The Mode S data parameters required to support Elementary Surveillance are provided in Table 3.

Military platforms are not required to process Mode S Comm-A uplink data unless the integration supports TCAS. If the installation supports TCAS, the Service Request shall be processed and the data off-loaded from the transponder.

Ref: ICAO Annex 10, paragraph 3.1.2.6.11, Vol. IV, amended.

Note1: If a Mode S transponder is not connected to a data bus, then the transponder may accept the Comm-A data and store it in the transponder’s queue and not process it.

Note2: In Any implementation, if the queue becomes overloaded it may be reset and the data discarded.

TABLE 2. ELEMENTARY SURVEILLANCE DOWNLINK FORMAT

Data Parameter Downlink Format (DF)

24-bit Address 11 (address only)

All other DF (addresses overlaid with parity)

Mode 3/A Code 5, 21

Aircraft Identification 20, 21

Data Link Capability Report 20, 21

Active Resolution Advisories 16 (TCAS)

Altitude 4, 20

Flight Status 4, 5, 20, 21

TABLE 3. ELEMENTARY SURVEILLANCE DATA PARAMETERS

Data Parameter Comm-B Data Selector (BDS)

Aircraft Identification BDS 2,0

Data Link Capability Report BDS 1,0

Common usage GICB capability report BDS 1,7

Active Resolution Advisories. BDS 3,0 (TCAS )

3.1.3.2 ENHANCED SURVEILLANCE

The Mode S data parameters required to support Enhanced Surveillance are provided in Table 4.

Enhanced Surveillance provides improvements in air traffic capacity and safety by means of access to additional aircraft parameters.

TABLE 4. ENHANCED SURVEILLANCE DATA PARAMETERS

Data Parameter Comm-B Data Selector (BDS)

Elementary Surveillance Functionality BDS 1,0 /1,7 /2,0 / (3,0 TCAS)

Magnetic Heading BDS 6,0

Indicated Airspeed BDS 6,0

Mach No. BDS 6,0

Vertical Rate BDS 6,0

Roll Angle BDS 5,0

Track Angle Rate or True Airspeed* BDS 5,0

True Track Angle BDS 5,0

Ground Speed BDS 5,0

Mode Control Panel/Flight Control Unit

(MCP/FCU) Selected Altitude (intentions)

BDS 4,0

*Note: If Track Angle Rate is not available, fill BDS 5,0 with True Airspeed .

3.1.3.3 BDS REGISTER UPDATE RATES

Table 5 specifies the minimum update rate at which the Comm-B Data Selector (BDS) data in each register shall be reloaded with valid data. The value in BDS 2,0 register may be maintained by the transponder as long as power is applied to the unit.

TABLE 5. BDS REGISTER UPDATE RATES

BDS Register Assignment Minimum Update

Rate

1,0 Data link capability report ≤ 4.0 s (Note 1)

1,7 Common usage GICB capability report 1.0 s

2,0 Aircraft identification 5.0 s

3,0 TCAS active resolution advisory (Note 2)

4,0 Aircraft intention 1.0 s

5,0 Track and turn report 1.0 s

6,0 Heading and speed report 1.0 s

Note 1: The data link capability report must be updated within one second of the data changing and at least every four seconds thereafter.

Note 2: BDS Register 3,0 updates are only required for TCAS-equipped aircraft as per ICAO Annex 10 Volume

III.

Note 3: BDS Register 4,0; 5,0; and 6,0 updates are not required for Elementary Surveillance.

Ref: ICAO Annex 10 Volume III, Table 2.1 page 5-64, amended.

3.1.4 MODE S SQUITTERS

Mode S Level 2 transponders shall be capable of supporting Acquisition Squitter whenever

Mode S is enabled. Additionally, Mode S Level 2 transponders should be capable of supporting

Extended Squitter for future growth to Automatic Dependent Surveillance-Broadcast (ADS-B).

Ref: ICAO Annex 10 Volume IV, paragraph 2.1.5.1.2, amended.

a. Acquisition Squitter.

The Mode S transponder shall have the capability to generate acquisition squitters (DF 11).

b. Extended Squitter.

Extended squitter (DF 17-19) is an objective capability that may be integrated to provide ADS-B functionality.

3.1.5 MODE S TRANSPONDER TRAFFIC ALERT AND COLLISION AVOIDANCE

SYSTEM (TCAS II) CAPABILITY

Mode S transponders on aircraft equipped with a TCAS II system shall have data link Comm-

U/V (UF/DF 16) capability. These transponders shall have the ability to interface with both an

FAA TSO-C119B and RTCA/DO-185A capable TCAS II unit. Mode S systems on aircraft that are equipped with TCAS shall be capable of processing all Comm-A and Comm-U message contents designated for the TCAS processor.

Ref: (1) DoD AIMS 97-1000, Para.3.14.5 (2) ICAO Annex 10 Part IV, Para. 3.1.2.8

3.1.5.1 MODE S TRANSPONDER / TCAS INTERFACE

An RTCA/DO-185A compatible transponder shall annunciate its capability to the on-board

TCAS via a dedicated ARINC 429 interface. Likewise, an RTCA/DO-185A compatible TCAS annunciates its capability to the on-board transponder via a separate, dedicated ARINC 429 interface. The capability of the transponder/TCAS system is then limited to the capability of either the transponder or TCAS unit having least capability.

Ref: ICAO Annex 10 Part IV, Para. 3.1.2.8

3.1.6 EMERGENCY

An emergency feature shall be provided for Modes 1, 2, 3/A, and S replies. When emergency is selected, the transponder shall reply in all four modes 1, 2, 3/A, and S irrespective of the settings of those modes. When Mode S is enabled, selecting emergency shall cause the Flight Status field of DF=4, 5, 20, and 21 Mode S replies to indicate a permanent alert condition.

Ref: DOD AIMS 97-1000, Para. 3.2.9 and 3.14.8.4

3.1.7 TRANSPONDER CONTROLS

The Mode S controls shall be implemented as detailed in Table 6.

TABLE 6. CONTROLS FOR MODE S TRANSPONDERS

Parameter Value Notes

Mode S Enable ON/OFF This enables or disables replies to Mode S interrogations. Depending on the Mode S level of integration into the aircraft will determine the Mode S reply level capability. Ref. AIMS 97-1000, para. 3.14.7.2

Mode S Address 8-digit octal or

6-digit hex

This allows for entering of a Mode S 24-bit address. It can be entered as either an 8-digit octal value or a 6-digit hexadecimal value. The 8-digit octal value is recommended. If desired the capability to enter the address in either format may be provided.

Mode S Aircraft

ID

XXXXXXXX This allows for entering of the aircraft ID associated with the flight plan. The value entered contains up to 8 alphanumeric characters with the unused trailing characters to be space characters. (see note below)

Mode S Max.

Airspeed

XXXX This allows for the entering of an aircraft's max cruising airspeed. The value is typically set once. Ref. ICAO Annex

10 Volume IV Para. 3.1.2.8.2.2.

Mode S Extended

Squitter

ON/OFF This is a growth option and may be implemented at a future date. The control turns extended squitter on or off. This squitter provides additional surveillance information about the aircraft.

Mode S Enhanced

Surveillance

ON/OFF This control turns on or off the transmission of

Enhanced Surveillance parameters. When off the transponder will operate in Elementary Surveillance mode only. Ref. AIMS 97-1000, para. 3.14.7.2

MIC/Ident ON/MIC/OFF This momentary switch enables the Ident function. If integrated to the microphone keyline the Ident function may also be enabled when the microphone is keyed.

Antenna Select TOP/BOT/DIV This selects the antenna mode – Top (UP), Bottom (LO), or Diversity (DIV). Platforms are required to operate in

Diversity at all times with selection available for maintenance purposes.

Note: Mode S Aircraft ID entry must be entered in accordance with DoD FLIP General Planning, chapter 4. This reference limits the entry of flight ID to 7 alphanumeric characters.

3.1.8 ALTITUDE CODE

The altitude code is reported as a 13-bit data field in DF 4 and 20 replies. The desired altitude report shall be in 25 ft. increments. However in cases where that capability is not available, reporting in 100 ft. increments will be acceptable.

3.2 NAVY MODE S 24-BIT ADDRESS

All Navy aircraft that are Mode S equipped shall have “stored” into the aircraft a Mode S 24-bit address assigned to that aircraft and shall have the capability to enter a Selectable Mode S 24-bit

Address.

Note: “Stored” is defined as follows:

The address may be resident in a piece of hardware, a non-volatile software code, a fixed cable wiring technique, or some other design.

3.2.1 MODE S 24-BIT DEFAULT ADDRESS

U.S. Navy aircraft shall have a single, unique 24-bit Mode S address that is called the 24-bit

Default Address. This 24-bit Default Address is cross-referenced to an aircraft Bureau Number

(BUNO). This Default Address stays with the aircraft until aircraft end of life.

3.2.2 MODE S 24-BIT SELECTABLE ADDRESS

U.S. Navy aircraft shall have the capability to change (overwrite) the Mode S 24-bit Default

Address to a Mode S 24-bit Selectable Address. When changing the Mode S 24-bit address

Mode S should be disabled and preferably the aircraft should be on the ground.

3.2.3 POWER INTERRUPTIONS AND 24-BIT ADDRESS

Power interruptions (no power condition) to the transponder shall not negatively affect aircraft’s storage of the 24-bit Default Address. Current policy for transponder integrations is as follows:

3.2.3.1 POWER INTERRUPTION – AIRBORNE.

When the aircraft is airborne and the aircraft transponder is operating with a 24-bit Selectable

Address, and power fails, the transponder shall “restart” using either the 24-bit Selectable

Address or revert to the 24-bit Default Address.

3.2.3.2 POWER INTERRUPTION – WEIGHT ON WHEELS.

After mission completion and all power is removed from the aircraft, and the transponder system is restarted, the 24-bit Default Address shall be used unless there is a mission planning over-ride or operator action to input a 24-bit Selectable Address.

APPENDIX A. ACRONYMS AND ABBREVIATIONS

ACAS Airborne Collision Avoidance System

ADS-B Automatic Dependent Surveillance- Broadcast

AIMS Air Traffic Control Radar Beacon System, Identification Friend or Foe, Mark XII System

ATC Air Traffic Control

ATCRBS Air Traffic Control Radar Beacon System

ATM Air Traffic Management

CNS/ATM Communication, Navigation, Surveillance / Air Traffic Management

CNO Chief of Naval Operations

CONOPS Concept of Operations

DF Downlink Formats

DoD Department of Defense

EUR European

EUROCAE European Organization for Civil Aviation Electronics

EUROCONTROL European Organization for the Safety of Air Navigation

FAA Federal Aviation Administration

FL Flight Level in hundreds of feet (FL100=10,000 feet)

FRD Functional Requirements Document

GICB Ground Initiated Comm-B

ICAO International Civil Aviation Organization

ID Identification

IFR Instrument Flight Rules

IIMSES Initial Implementation of Mode S Enhanced Surveillance

MCP/FCU Mode Control Panel/Flight Control Unit

Mode S Mode Select

MTL Minimum Triggering Level

NATO North Atlantic Treaty Organization

RA Resolution Advisory

RTCA RTCA, Inc., Formerly Radio Technical Commission for Aeronautics

SARPS International Standards and Recommended Practices

SSR Secondary Surveillance Radar

STANAG (NATO) Standardization Agreement

TA Traffic Advisory

TCAS Traffic Alert and Collision Avoidance System

UF Uplink Formats

VFR Visual Flight Rules