Performance Based Communications and Surveillance (PBCS)

Airspace

Eddie sez:

The best way to understand PBCS is to think of PBN:

  • You must fly to a certain level of Required Navigation Performance (RNP) to use the airspace regulated under Performance Based Navigation (PBN). Over most oceanic airspace, for example, you need RNP-4 or RNP-10. Those refer to certain levels of navigation accuracy.
  • You must communicate to a certain level of Required Communications Performance (RCP) to use the airspace regulated under Performance Based Communication and Surveillance (PBCS). For most oceanic airspace, for example, you need RCP-400. That refers to the time in seconds between the person on the ground asking you something and your response getting back to him or her.
  • Air Traffic Control must be able to exchange data with your aircraft to a level of Required Surveillance Performance (RSP) to use the airspace regulated under Performance Based Communication and Surveillance (PBCS). For most oceanic airspace, for example, you need RSP-400. That refers to the time in seconds the person on the ground gets your surveillance data.

As of 2020 we seem to have two types of airspace when it comes to RCP and RSP. While not completely correct, you can think of them as PBCS and non-PBCS.

Everything here is from the references shown below, with a few comments in an alternate color.

Last revision:

2020-12-14

Cover Story:

2018-02-10


Location

PBCS can be applied just about anywhere you need to cram more and more aircraft into the same airspace. Here are a few examples. In the North Atlantic, as of early 2020, only the "core" North Atlantic Tracks used PBCS. By late 2020, none of the tracks were using PBCS because the volume of traffic was too low to justify it.

[ICAO Doc 9869, ¶1.6.5] RCP and RSP specifications can be applied to communication and surveillance capabilities in an airspace or to support an ATM operation. Examples of such applications include:

  1. a defined airspace (e.g. North Atlantic or Pacific Regions) for safety or to support application of a 5-minute or 55.5 km (30 NM) longitudinal separation minimum;
  2. a fixed ATS route (e.g. between Sydney, Australia, and Auckland, New Zealand);
  3. c) random track operations (e.g. between Hawaii and Japan); or
  4. d) a volume of airspace (e.g. a block altitude on a specified route).

Performance Standards

As pilots, we have an intuitive understanding of RNP. We are in the business of keeping on course, after all. But what of RCP and RSP?

[AC 90-117, ¶22.15.1] An RCP specification represents operational parameters for the complete communication transaction. It is identified by a designator (e.g., RCP 240 or RCP 400) in order to simplify the designator naming convention and to make the RCP Expiration Time (ET) readily apparent to airspace planners, aircraft manufacturers, and operators. The designator represents the value for the communication ET after which the initiator is required to revert to an alternative procedure. The RCP specifications are applied to achieve the performance required of the communication process and may support aircraft separation minima.

[ICAO Doc 9869, ¶2.2.1.13] RCP 240 may be applied to maintain the performance for normal means of communication, which supports controller intervention capability in procedurally controlled airspace, where the separation minimum applied is predicated on communication performance.

[ICAO Doc 9869, ¶2.2.1.14 RCP 400 may be applied to maintain the performance for emerging technology (e.g. satellite voice) used to provide normal means of communication supporting controller intervention capability in procedurally controlled airspace, where the separation minimum applied is based on position reporting at compulsory reporting points. RCP 400 may also be applied to maintain the performance required for emerging technologies used to provide alternative means of communication, that may be required in combination with the normal means of communication, to which RCP 240 is applied.

You can think of RCP 400 as old school and RCP 240 as full up CPDLC and ADS-C at the highest levels available in 2020.

[AC 90-117, ¶22.16.3] An RSP specification is identified by a designator (e.g., RSP 180) in order to simplify the designator naming convention and to make the RSP Data Operational Overdue Time (OT) readily apparent to airspace planners, aircraft manufacturers and operators. The designator represents the value for the surveillance data delivery time when the surveillance data delivery is considered overdue. RSP specifications are applied to airspace based on specific objectives (e.g., the performance required of the surveillance process used to support particular separation minima). The RSP specification is a set of requirements/operational parameters for ATS provision and associated ground equipment, aircraft capability, and operations needed to support performance-based surveillance. Surveillance performance requirements are included and allocated to system components (Required Surveillance Technical Performance (RSTP)). It includes surveillance data delivery time, continuity, availability, integrity, and safety. A specified RSP specification is intended to define the surveillance performance required of a surveillance process to support a particular ATM function. RSP specification is applied to the airspace, route, or procedure based on the most stringent RSP specification of the required ATM functions.

[ICAO Doc 9869, ¶2.4.1.1] RSP 180 may be applied to maintain the performance for normal means of surveillance, which supports controller intervention capability in procedurally controlled airspace, where separation minimum applied is predicated on surveillance performance.

[ICAO Doc 9869, ¶2.4.1.11] RSP 400 may be applied to maintain the performance for emerging technology (e.g. satellite voice) used to provide normal means of surveillance supporting controller intervention capability in procedurally controlled airspace, where the separation minimum being applied is based on position reporting at compulsory reporting points. RSP 400 might also be applied to maintain the performance required for emerging technologies used to provide alternative means of surveillance, that may be required in combination with the normal means of surveillance, to which RSP 180 is applied.

You can think of RSP 400 as old school and RSP 180 as full up CPDLC and ADS-C at the highest levels available in 2020.

Documentation / Certification

Aircraft Eligibility

[AC 90-117, ¶3.3] Due to the complexity of the criteria to determine eligibility, the operator must obtain a statement of compliance from the entity that owns the design approval for their data link installation. This may be the aircraft manufacturer, the operator, the manufacturer of the data link system, or another party. The statement of compliance should be provided in the AFM, AFM Supplement, or other acceptable document.

Authorization

You will need A056 to use datalink outside the United States and you will have to be authorized specifically for to use PBCS airspace at that level.

[FAA Order 8900.1, Volume 3, Chapter 18, §3, A056, ¶B.] This paragraph is for U.S. aircraft and operators conducting data link communications operations under parts 91, 91K, 121, 125 (including part 125 LODA holders), and 135. NOTE: Part 91 operators do not require operational authorization for the use of data link in U.S. domestic airspace. For data link operations in oceanic and remote continental airspace and/or foreign countries requiring specific data link approval, LOA A056 applies.

[FAA Order 8900.1, Volume 3, Chapter 18, §3, A056, ¶C. 1) b)] If applicable, the SOC should reference AC 20-140B or a later revision for any of the following performance specifications:

  • RCP 400, RCP 240; or
  • RSP 400, RSP 180.

Advisory Circular 90-117, Data Link Communications, 10/3/17, Department of Transportation

ICAO Doc 9869, Performance-based Communication and Surveillance (PBCS) Manual), Second Edition, 2017, International Civil Aviation Organization

FAA Orders 8400 and 8900