Performance Based Communication and Surveillance System, PBCS

Required Communication Performance, RCP and Required Surveillance Performance, RSP specifications describe the ATS provision of communication/ services, aircraft capability, and the aircraft operator in terms of seconds. "RVSM for your Datalink" is a good analogy. Similar to the PBN concept, this “PBCS” includes real-time monitoring and alerting functionality in the aircraft capability and post-implementation monitoring programs, on a local and regional basis, with a global exchange of information. Look for this to be first implemented into the NAT Region March 2018. 

Required Communication Performance, RCP

Each RCP type denotes values for communication transaction time, continuity, availability, and integrity applicable to the most stringent operational communication transaction supporting an ATM function. The designator (i.e. RCP 400, 180, 120 ect.) represents the value for the maximum communication transaction time after which the initiator should revert to an alternative communication procedure. This is usually HF radio in oceanic/remote regions.

Besides a time threshold, an RCP specification represents operational values for communication transaction time, continuity, availability, and integrity applicable to the communication transaction supporting an ATM function. This elapsed time includes technical communication performance, average human-machine interface and average cockpit response times. This is commonly referred to as “Cockpit thinking times”.

Required Surveillance Performance, RSP

An RSP specification is a label (i.e. RSP 180, 400) represents the values assigned to RSP parameters for surveillance transaction time (in seconds), continuity, availability, and integrity. A specified RSP specification is intended to define the surveillance performance required of a surveillance process to support a particular ATM function.

Traditionally, surveillance over oceanic and remote areas was limited to pilot position reports via High Frequency, HF radio. When crossing a compulsory reporting point, the pilot would contact the ATSU and report: identification, position, time, altitude, next position reporting point, name of succeeding reporting point, and remarks. Once the aircraft entered a radar environment, pilot reports were eliminated. Surveillance in oceanic and remote airspace is accomplished much more accurately through the use of ADS-C. As with CPDLC, ADS-C requires certain performance requirements for operational surveillance in support of specific ATM functions. This includes the transmission of aircraft position, velocity and intent with a specified precision, accuracy and update rates.

Air Traffic Management Uses

In combination with RNP, RCP and RSP enables the efficient use of airspace by allowing ATM operations at reduced separations while maintaining the same low probability of air traffic collision. This is the heart of the performance based concept. Domestic USA enroute services are expected to begin in 2019 using existing FANS 1/A aircraft to deliver CPDLC services in the U.S. NAS en route airspace. 
Full enroute services are expected to begin in 2025 and will provide advanced services, such as four-dimensional (4D) trajectories, dynamic required navigation performance, advanced flight interval management with ATC wind information.

Datalink Monitoring and Approval Requirements

A new A-056 approval template is under construction. Current A-056 LOA/OpsSpecs holders should be prepared with CPDLC and ADS-C monitoring data on their airframes and operations for this implementation 2018. Since 2009 the rates of equipage, connection and continuity have been tracked by the FAA. This data is being shared with Japan and the NAT region. FAA Washington is in the works of producing a monitoring webpage similar to RVSM monitoring results to publish this data. This required monitoring data will also need reports from your communication service provider on your FANS1/a fail/success rates. Meanwhile, for further information on your specific airframe monitoring results, please contact Theresa Brewer, FAA Air Transportation System Evaluation Division, Separation Standards Analysis Branch, Office Phone: 609-485-5106, theresa.brewer@faa.gov

All new A-056 approvals are to be initially approved with a provision to get monitoring and provide adequate sampling to remain qualified. 100 data points are the desired level of sampling. One-off installations via STC's will be handled individually. Operators need to be diligent in getting problem reports to regional monitoring authorities. The next best option is to make your POI and the ATC agency involved aware of data link problems encountered. New guidance in #4444 and a yet to be published AC (replacing AC 120-70C) are on the way. Expected publication is March 2017.

More Flight Plan Equipment Codes

These documents will reference the use of "P-Codes" on the flight plan forms. P-1, 2, 3 or 4 when inserted into block#10 will indicate what level of RCP your CPDLC connections are operating at (400sec or 240sec).  Here is an example:

Item 10: Equipment, 10A Communication and Navigation (Before the diagonal mark)

P1, CPDLC RCP 400                          P2, CPDLC RCP 240              P3, SATVOICE RCP 400

P4-P9, Reserved

These are to be further explained in block#18 behind the DAT/ and SUR/ entries. D-1 and G-1 entries will have a similar description for the ADS-C connection. MMEL and MEL's will need to be updated with this RCP/RSP information. Operators are cautioned that an MEL downgrade to RCP or RSP needs to be indicated on the current flight plan. Without a J-5 or J-7 code on the flight plan, expect to be denied routing thru FANS1/a required airspace due to ATOP computer programming. ATC expects this programming to be complete by summer of 2017.

Bottomline

1. Flight plan equipment codes are dependent on installation, functionality and approvals not just an STC/TC installation

2. Pilots need to understand that “STBY” is a quick and legitimate response to ATC and will help improve response time monitoring

3. In most cases, prior datalink performance monitoring is required for operating approval

4. Problem reporting to POI's and regional monitoring agencies will be key to troubleshooting FANS communication and surveillance problems