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ADS-B-Automatic Dependent Surveillance Broadcast (ADS-C)

Short (Certificate) Courses for Pilots-in-Service

Min. Academic & Professional Level

Intermediate & PPL,CPL, ATPL Holders & Flight Instructors

Course Designed for:

PPL,CPL, ATPL Holders, Airlines & GA Pilot-in-Service, Flight Instructors of Flying Clubs & Flight Simulators

Short Course Modules:

Content:

Module 1: Introduction to ADS-C

  • Understanding the concept and significance of ADS-C.
  • Historical development and evolution of ADS-C.
  • Importance of ADS-C in modern aviation.
  • Overview of the course content.

Module 2: ADS-C Technology and Components

  • Basic components of ADS-C systems.
  • ADS-C data reporting modes (event-driven, periodic).
  • Data link and GPS integration.
  • Avionics and communication equipment.

Module 3: ADS-C Data Reporting and Message Formats

  • Types of ADS-C reports (contract initiation, periodic, event).
  • Data elements included in ADS-C reports.
  • Message formats and protocols.
  • Data link performance and reliability.

Module 4: ADS-C Applications and Benefits

  • Surveillance and tracking applications.
  • Fuel and time-saving benefits.
  • Operational advantages for airlines and ATC.
  • Real-world case studies of ADS-C benefits.

Module 5: ADS-C Regulations and Compliance

  • International and national ADS-C regulations.
  • Equipage mandates and compliance deadlines.
  • Certification requirements for ADS-C equipment.
  • Non-compliance penalties and implications.

Module 6: ADS-C Integration and Installation

  • Retrofitting and upgrading aircraft for ADS-C.
  • Installation considerations and challenges.
  • ADS-C equipment testing and validation.
  • Cost and time implications of integration.

Module 7: ADS-C Data Privacy and Security

  • Data protection and privacy concerns.
  • Cybersecurity measures for ADS-C systems.
  • Threats and vulnerabilities in ADS-C networks.
  • Secure data sharing protocols.

Module 8: Future Developments and Evolving Standards

  • Emerging technologies in ADS-C.
  • Next-generation ADS-C systems.
  • Harmonization of global ADS-C standards.
  • Research and development in ADS-C.

Module 9: ADS-C Implementation and Best Practices

  • Successful ADS-C implementation case studies.
  • Best practices for optimizing ADS-C performance.
  • Training and proficiency for ADS-C users.
  • Continuous improvement and future outlook.

Module 10: ADS-C in Air Traffic Management

  • Role of ADS-C in modern ATC systems.
  • Collaborative decision-making and ADS-C.
  • ADS-C and reduced separation standards.
  • Challenges and opportunities in ADS-C for ATC.

An Overview:

Definition:

Automatic Dependent Surveillance-Contract (ADS-C) is another technology used in aviation, particularly in the context of long-range flights over oceanic or remote areas where traditional radar coverage is limited or non-existent. 

ADS-C is a communication system that allows an aircraft to periodically transmit its position and other flight-related information to ground stations via satellite communication links. It is primarily used to enhance aircraft surveillance and improve communication between the aircraft and air traffic control, even when the aircraft is out of radar coverage.

Here’s how ADS-C works:

Periodic Reporting: In ADS-C, the aircraft’s avionics system determines when to send position reports based on predefined parameters or events. These reports can include information such as the aircraft’s position, altitude, heading, groundspeed, and other flight-related data.

Satellite Communication: Instead of broadcasting data to ground stations like in ADS-B, ADS-C uses satellite communication to relay the aircraft’s reports to a ground-based server or data center.

Data Analysis: The ground-based server or data center processes the received ADS-C reports. Air traffic controllers and airline operations centers can access this data to monitor the aircraft’s position and track its progress.

Customization: The parameters and events that trigger ADS-C reports can be customized based on flight plans, airspace requirements, and other factors. For example, the system might be configured to send a report when the aircraft crosses a certain waypoint or when there’s a change in altitude.

Benefits of ADS-C include:

Extended Surveillance Coverage: ADS-C extends the ability to track and communicate with aircraft beyond the range of traditional radar systems. This is particularly useful in remote or oceanic regions where radar coverage is limited.

Enhanced Safety: By providing regular updates on an aircraft’s position and status, ADS-C improves situational awareness for both air traffic controllers and pilots, enhancing safety.

Optimized Routing: Airlines can use ADS-C data to analyze flight performance, optimize routes, and make real-time adjustments based on changing weather conditions or airspace restrictions.

Fuel Efficiency: By allowing aircraft to follow more precise flight paths and adjust routes based on real-time data, ADS-C can contribute to fuel savings.

Cost Savings: ADS-C can reduce the need for constant voice communication between pilots and air traffic control, which can lead to cost savings in terms of pilot workload and communication expenses.

It’s important to note that ADS-C is typically used in conjunction with other communication and surveillance technologies, such as ADS-B, to provide a comprehensive picture of an aircraft’s position and status. ADS-C-equipped aircraft can transmit data via satellite communication systems like ACARS (Aircraft Communications Addressing and Reporting System) or other data link solutions. Like ADS-B, the effectiveness of ADS-C relies on its integration into overall air traffic management systems and the cooperation of aviation

What is ADS-C?

  • In a similar way to ADS-B, ADS-C (Automatic Dependent Surveillance – Contract) transmits regular and highly accurate position reports to Air Traffic Control.
  • However, the “Contract” element of ADS-C refers to a contract, established by the ground station, between the aircraft and that ground station. This contract is established and controlled by the ground station.

What Are The Main Differences Between ADS-B and ADS-C?

  • The main differences between ADS-B versus ADS-C revolve around the types of connections, how the systems are used, and the ways in which they communicate.

ADS Broadcast versus Contract

  • ADS-B “broadcasts” reports to any station capable of receiving them. These broadcasts are automatic and continuous and are not in response to requests from ground stations (as opposed to ADS-C).
  • ADS-C is a “contract” between the aircraft and a specific ground station. The contract is established and controlled by the ground station and this contract determines what information is to be sent and when it will be transmitted – the information is not broadcast to all stations as with ADS-B.
  • ADS-B aircraft positions are updated much more often than those operating ADS-C. As such, ADS-B provides a much more accurate picture to Air Traffic Control. The accuracy of the position reporting allows ADS-B position plots to be considered surveillance control.
  • ADS-C however is updated over longer periods (approx. 10-minute intervals) and such is typically used over remote and oceanic areas.

ADS Transmission Method

  • ADS-B is transmitted by the aircraft’s Mode S Transponder and therefore has a more limited range.
  • ADS-C is transmitted over the ACARS network via Satellite and therefore is not limited in range as for ADS-B.
  • ADS-C can operate either with CPDLC (Controller Pilot Data Link Communications) or independently on its own

Definition

Automatic dependent surveillance — contract (ADS-C): means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft, via a data link, specifying under what conditions ADS-C reports would be initiated, and what data would be contained in the reports. (ICAO)

Description

Although the names are similar, ADS-C and ADS-B are two different applications.

Automatic dependent surveillance – broadcast (ADS-B), like Primary Surveillance Radar (PSR) and Secondary Surveillance Radar (SSR) is an ATS surveillance system which allows ATC to automatically and repeatedly access data from all suitably equipped aircraft and both use and re-broadcast it to suitably equipped other aircraft within range.

Automatic dependent surveillance – contract (ADS-C) uses the same systems on board the aircraft to automatically transmit similar information – aircraft position, altitude, speed, elements of navigational intent and meteorological data – only to one or more specific Air Traffic Services Unit (ATSU) or AOC [1] facilities for surveillance and/or route conformance monitoring.

Data provision by an aircraft is generated in response to a request within the terms of the ADS contract held by the ground system. This contract identifies the types of information and the conditions under which reports are to be sent by the aircraft. Some types of information are included in every report, while other types are provided only if specified in an ADS contract request. The aircraft can also send unsolicited ADS-C emergency reports to any ATSU that has an ADS contract with the aircraft.

An ATSU system may request multiple simultaneous ADS contracts with a single aircraft, including one periodic and one event contract, which may be supplemented by any number of demand contracts. Up to five separate ground systems may request ADS contracts with a single aircraft.

ADS Contract Types

After receiving a logon request, the ATSU will need to establish ADS contract(s) with the aircraft before it can receive any ADS-C reports. There are three types of ADS contracts:

a) Periodic contract;

b) Demand contract; and

c) Event contract.

The ground system can establish ADS contracts without flight crew action provided that ADS-C in the aircraft system is not selected off. The flight crew has the ability to cancel all contracts by selecting ADS-C off and some aircraft systems allow the flight crew to cancel an ADS contract with a specific ATSU.

Periodic Contract

A periodic contract allows an ATSU to specify:

a) The time interval at which the aircraft system sends an ADS-C report; and

b) The optional ADS-C groups that are to be included in the periodic report. Each optional group may have a unique modulus which defines how often the optional group is included with the periodic report (e.g. a modulus of five indicates that the optional group would be included with every fifth periodic report sent).

Demand Contract

  • A demand contract allows an ATSU to request a single ADS-C periodic report. A demand contract does not cancel or modify any other ADS contracts that may be in effect with the aircraft.
  • The ADS-C application also supports emergency alerting. An ADS-C emergency report is a periodic report that is tagged as an “emergency” report, allowing the emergency situation to be highlighted to ATC.

An ADS-C emergency can be triggered by the flight crew in a number of ways:

a) Manually, by selecting the ADS-C emergency function;

b) Indirectly, by triggering another type of emergency alerting system (e.g. transmission of a CPDLC position report or selection of an SSR emergency code); and

c) Covertly (The availability of that functionality may vary between aircraft types).

Once an ADS-C emergency has been triggered, under normal circumstances the avionics will continue to transmit ADS-C emergency periodic reports until the flight crew de-selects the ADS-C emergency function.

Event Contract

An event contract allows an ATSU to request an ADS-C report whenever a specific event occurs. An ATSU can establish only one event contract with an aircraft at any one time. However, the event contract can contain multiple event types. These types of optional events include:

a) Waypoint change event (WCE);

b) Level range deviation event (LRDE);

c) Lateral deviation event (LDE); and

d) Vertical rate change event (VRE).

An event contract remains in effect until the ATSU cancels it or until the event(s) used to trigger the report occurs. The waypoint change event contract will trigger a report for all waypoint changes. All other event contracts will trigger a report on the first occurrence and then, if necessary, the ATSU will need to request a new event contract indicating all desired event types.

ADS-C Reports

The aircraft system sends specific aircraft data in different groups of an ADS-C report. Each group contains different types of data. An ADS-C event report contains only some of the groups, which are fixed. The ADS-C periodic report can contain any of the ADS-C groups, which the ATSU specifies in the contract request. The ADS-C report groups consist to:

  • Basic group
  • Flight identification group
  • Earth reference group
  • Air reference group
  • Airframe identification group
  • Meteorological group
  • Predicted route group
  • Fixed projected intent group
  • Intermediate projected intent group
    • The ATSU may use an ADS-C report for a variety of purposes. These include:
  • Establishing and monitoring of traditional time-based separation minima;
  • Establishing and monitoring of distance-based separation standards;
  • Flagging waypoints as ‘overflown’;
  • Updating estimates for downstream waypoints;
  • Route and level conformance monitoring;
  • Updating the display of the ADS-C position symbol, and the associated extrapolation;
  • Generating (and clearing) alerts;
  • Generating (and clearing) ADS-C emergencies;
  • Updating meteorological information; and
  • Updating other information in the flight plan held by the ATSU.
  • For more detailed information on ADS-C principles of operation, capabilities and merits see the ICAO Global Operational Data Link Document (in Further Reading), Section 2.2.6.

Course Modules:

Module 1: Introduction to ADS-C
  1. Understanding the concept and significance of ADS-C.
  2. Historical development and evolution of ADS-C.
  3. Importance of ADS-C in modern aviation.
  4. Overview of the course content.
Module 2: ADS-C Technology and Components
  1. Basic components of ADS-C systems.
  2. ADS-C data reporting modes (event-driven, periodic).
  3. Data link and GPS integration.
  4. Avionics and communication equipment.
Module 3: ADS-C Data Reporting and Message Formats
  1. Types of ADS-C reports (contract initiation, periodic, event).
  2. Data elements included in ADS-C reports.
  3. Message formats and protocols.
  4. Data link performance and reliability.
Module 4: ADS-C Applications and Benefits
  1. Surveillance and tracking applications.
  2. Fuel and time-saving benefits.
  3. Operational advantages for airlines and ATC.
  4. Real-world case studies of ADS-C benefits.
Module 5: ADS-C Regulations and Compliance
  1. International and national ADS-C regulations.
  2. Equipage mandates and compliance deadlines.
  3. Certification requirements for ADS-C equipment.
  4. Non-compliance penalties and implications.
Module 6: ADS-C Integration and Installation
  1. Retrofitting and upgrading aircraft for ADS-C.
  2. Installation considerations and challenges.
  3. ADS-C equipment testing and validation.
  4. Cost and time implications of integration.
Module 7: ADS-C Data Privacy and Security
  1. Data protection and privacy concerns.
  2. Cybersecurity measures for ADS-C systems.
  3. Threats and vulnerabilities in ADS-C networks.
  4. Secure data sharing protocols.
Module 8: Future Developments and Evolving Standards
  1. Emerging technologies in ADS-C.
  2. Next-generation ADS-C systems.
  3. Harmonization of global ADS-C standards.
  4. Research and development in ADS-C.
Module 9: ADS-C Implementation and Best Practices
  1. Successful ADS-C implementation case studies.
  2. Best practices for optimizing ADS-C performance.
  3. Training and proficiency for ADS-C users.
  4. Continuous improvement and future outlook.
Module 10: ADS-C in Air Traffic Management
  1. Role of ADS-C in modern ATC systems.
  2. Collaborative decision-making and ADS-C.
  3. ADS-C and reduced separation standards.
  4. Challenges and opportunities in ADS-C for ATC.
These modules provide a comprehensive overview of ADS-C technology, its applications, regulatory aspects, security concerns, and its role in enhancing aviation safety and efficiency.