2.15.3 RCP Framework and Actual Communication Performance (ACP). In Figure 2-7, Actual Communications Performance (ACP), the combined uplink and downlink performance of ground systems, communication service, and aircraft systems is the Actual Communication Technical Performance (ACTP). Pilots and controllers should respond as soon as possible as part of the overall human performance. Human performance combined with ACT results in ACP. ACP is an indicator of the operational performance of a communication system which includes the human and technical components. Human performance considers such factors as training, procedures, and human-machine interface (HMI). Technical performance comprises the installed elements of communication performance operating together to meet the intended function. ACP is assessed in the same terms and parameters as an RCP specification, its allocations, and other relevant operational criteria provided by an RCP specification. Operationally, an appropriate level of communication performance is required for aircraft systems, communications networks, and ground systems.
Note: In ICAO documentation, pilot response time is called Pilot Operational Response Time (PORT).
Figure 2-8. RCP 240 Illustration RCP 240
99.9% ≤ 240 sec / 95% ≤ 210 sec Pilot Required Communication Controller Technical Performance RCTP RCTP = 99.9% ≤ 150 sec / 95% ≤ 120 sec RCMP = 99.9% ≤ 210sec / 95% ≤ 180 sec Human Performance Technical Performance Human Performance (in seconds) (in seconds (in seconds)
99.9% 60 15 120 15 30 1=240 95% 60 10 100 10 30 • =210 Flight Crew Aircraft Network ATSU System Controller Systems 2-20
2.15.4 RCP 240 Illustration. As illustrated in Figure 2-8, RCP 240 Illustration, the controller sends a data link communication message through the ATSU via the CSP to the aircraft.
The Required Communication Technical Performance (RCTP) is the overall time for the communication to travel from the ATSU to the flight deck and return excluding human response time. RCTP should be less than or equal to 150 seconds for 99.9 percent of the operational time (ET) and must be less than or equal to 120 seconds for 95 percent of the nominal time (TT). The message arrives at the flight deck and the pilot should respond as soon as possible (i.e., ROGER (DM3)/WILCO (DM0), UNABLE (DM1), or STANDBY (DM2)). The pilot responds to the message and it travels back to the ATSU.
2.15.5 RCP 240 Specification Tables. Table 2-4, RCP 240 Transaction Time and Continuity Allocations–CPDLC, shows Transaction Time and Continuity allocations from the sender (controller) to responder (pilot) and back to sender (controller). RCTP consists of the ATSU system, network, and the aircraft system. Table 2-5, RCP 240 Availability Criteria (Aircraft System), provides the aircraft system availability criteria. Table 2-6, RCP 240 Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.
Table 2-4. RCP 240 Transaction Time and Continuity Allocations—CPDLC ACP Controller ATSU system Network Aircraft system Pilot Response Aircraft system Network ATSU system Controller
99.9% (ET) PC/ATSU (30) PATSU(15) PNET(120) PAIR(15) 60 PAIR(15) PNET(120) PATSU(15) PC/ATSU (30) 95% (TT) PC/ATSU (30) PATSU(10) PNET(100) PAIR(10) 60 PAIR(10) PNET(100) PATSU(10) PC/ATSU (30) Table 2-5. RCP 240 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-6. RCP 240 Integrity Criteria (Aircraft System) Integrity Parameter Integrity Value Compliance Means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration.
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Figure 2-9. RCP 400 Illustration
2.15.6 RCP 400 Illustration. As illustrated in Figure 2-9, RCP 400 Illustration, the controller sends a data link communication message through the ATSU through the CSP to the aircraft. The RCTP is the overall time for the communication to travel from the ATSU to the flight deck and return excluding human factors. RCTP should be less than or equal to 310 seconds for 99.9 percent of the operational time (ET) and must be less than or equal to 260 seconds for 95 percent of the nominal time (TT). The message arrives at the flight deck and the pilots should respond as soon as possible (i.e., ROGER (DM3)/WILCO (DM0), UNABLE (DM1), or STANDBY (DM2)). The pilot responds to the message and it travels back to the ATSU.
2.15.7 RCP 400 Specification Tables. Table 2-7, RCP 400 Transaction Time and Continuity Allocations—CPDLC, shows Transaction Time and Continuity allocations from the sender (controller) to responder (pilot) and back to sender (controller). RCTP consists of the ATSU system, network, and the aircraft system. Table 2-8, RCP 400 Availability Criteria (Aircraft System), provides the availability criteria for the aircraft system.
Table 2-9, RCP 400 Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.
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Table 2-7. RCP 400 Transaction Time and Continuity Allocations—CPDLC ACP Controller ATSU system Network Aircraft system Pilot Response Aircraft system Network ATSU system Controller
99.9% (ET) PC/ATSU (30) PATSU(15) PNET(280) PAIR(15) 60 PAIR(15) PNET(280) PATSU(15) PC/ATSU (30) 95% (TT) PC/ATSU (30) PATSU(10) PNET(240) PAIR(10) 60 PAIR(10) PNET(240) PATSU(10) PC/ATSU (30) Table 2-8. RCP 400 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-9. RCP 400 Integrity Criteria (Aircraft System) Integrity parameter Integrity value Compliance means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration.
2.16 Required Surveillance Performance (RSP).
2.16.1 Background. In the past, surveillance over oceanic and remote continental areas was limited to pilot position reports via HF radio. When crossing a compulsory reporting point, the pilot would contact the ATSU via a radio operator and report: identification, position, time, altitude, next PR point, name of succeeding reporting point, and remarks.
Once the aircraft entered a radar environment, pilot reports were eliminated. Today, along with voice pilot position reports, surveillance in oceanic and remote continental 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. In combination with RCP and RNP, RSP enables the efficient use of airspace by allowing reduced lateral and along-track separation of aircraft by supplying accurate and frequent updates of aircraft position.
2.16.2 RSP Concept. The concept of RSP relates to the surveillance component and complements RNP and RCP. A collective set of performance measures are established to ensure overall communication transactions and surveillance data deliveries are suitable for certain surveillance related goals. For example, the surveillance goal may be to achieve 30 nautical miles (NM) lateral and 30 NM along-track separation in oceanic 2-23
airspace. RSP is operationally derived and not based on any specific techniques, aircraft technologies, or architecture.
2.16.3 RSP Specification. 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.
2.16.4 RSP Parameters. RSP include the accuracy of the reported position, the latency in reporting the position to the controller, and the integrity, availability, and continuity of the surveillance data. The following describes the RSP parameters:
1. RSP Surveillance Data Transit Time. The maximum time for the reception of the surveillance data after which the controller should revert to an alternative procedure.
2. RSP Continuity. The minimum proportion of surveillance data delivery to be completed within the specified RSP surveillance data delivery time, given the service was available at the start of the delivery.
3. RSP Availability. The required probability that surveillance data can be provided.
4. RSP Integrity. The required probability that surveillance data delivery is completed with no undetected errors.
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Figure 2-10. RSP 180 Illustration
2.16.5 RSP 180 Illustration. In Figure 2-10, RSP 180 Illustration, the ATSU establishes an event contract with the aircraft with specific allocations described below:
1. From 1 to 2 (Aircraft). The aircraft reaches the particular event and is required to respond within 5 seconds or less 99.9 percent of the operational time (OT) and less than or equal to 3 seconds 95 percent of the nominal delivery time (DT).
2. From 2 to 3 (CSP). The signal is then transmitted through the communication service provider (CSP) network. This action must occur within 170 seconds or less for 99.9 percent of the OT and less than or equal to 84 seconds 95 percent of the DT.
3. From 3 to 4 (ATSU). From the (CSP) this message is sent through the ATSU which has a required performance of less than or equal to 5 seconds for
99.9 percent of the time and less than or equal to 3 seconds for 95 percent of the time. The total communication from the event to the controller must be less than or equal to 180 seconds with 99.9 percent probability (OT) and less than or equal to 90 seconds with 95 percent probability (DT).
2.16.6 RSP 180 Specification Tables. Table 2-10, RSP 180 Surveillance Data Delivery and Continuity Allocations—ADS-C, shows allocations for Required Surveillance Monitoring Performance/Required Surveillance Technical Performance (RSMP/RSTP) consisting of the aircraft system, network and ATSU. Table 2-11, RSP 180 Availability Criteria (Aircraft System), provides the availability criteria for the aircraft system.
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Table 2-12, RSP 180 Integrity Criteria (Aircraft System) provides the integrity criteria for the aircraft system.
Table 2-10. RSP 180 Surveillance Data Delivery and Continuity Allocations—ADS-C RSMP/RSTP Aircraft system Network ATSU
99.9% (OT) 5 170 5 95% (DT) 3 84 3 Table 2-11. RSP 180 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-12. RSP 180 Integrity Criteria (Aircraft System) Integrity parameter Integrity value Compliance means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration.
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Figure 2-11. RSP 400 Performance
2.16.7 RSP 400 Illustration. In Figure 2-11, RSP 400 Performance, the ATSU establishes an event contract with the aircraft with specific allocations described below.
1. From 1 to 2 (Aircraft). The aircraft reaches the particular event and is required to respond within 30 seconds or less 99.9 percent of the OT and less than or equal to 15 seconds 95 percent of the DT.
2. From 2 to 3 (CSP). The signal is then transmitted through the CSP network.
This action must occur within 340 seconds or less for 99.9 percent of the OT and less than or equal to 270 seconds 95 percent of the DT.
3. From 3 to 4 (ATSU). From the CSP this message is sent through the ATSU which has a required performance of less than or equal to 30 seconds for
99.9 percent of the time and less than or equal to 15 seconds for 95 percent of the time. The total communication from the event to the controller must be less than or equal to 400 seconds with 99.9 percent probability (OT) and less than or equal to 300 seconds with 95 percent probability (DT).
2.16.8 RSP 400 Specification Tables. Table 2-13, RSP 400 Surveillance Data Delivery and Continuity Allocations—ADS-C, shows allocations for Required Surveillance Monitoring Performance/Required Surveillance Technical Performance (RSMP/RSTP) consisting of the aircraft system, network and ATSU. Table 2-14, RSP 400 Availability Criteria (Aircraft System), provides the availability criteria for the aircraft system.
Table 2-15, RSP 400 Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.
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Table 2-13. RSP 400 Surveillance Data Delivery and Continuity Allocations—ADS-C RSMP/RSTP Aircraft system Network ATSU
99.9% (OT) 30 340 30 95% (DT) 15 270 15 Table 2-14. RSP 400 Availability Criteria (Aircraft System) Availability Parameter Efficiency Safety Compliance Means Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design, pre-implementation demonstration Table 2-15. RSP 400 Integrity Criteria (Aircraft System) Integrity parameter Integrity value Compliance means Integrity (I) Malfunction = 10-5 per flight hour Analysis, safety requirements, development assurance level
(e.g. Level C software) commensurate with integrity level, pre-implementation demonstration. The aircraft end system shall be capable of detecting errors that would result in corruption, introduced by the communication service.
2.17 High Frequency Data Link (HFDL). Over the past few decades HF has provided an effective means of voice communication over long distance in oceanic and remote continental airspace. HF communication is no longer restricted to voice and provides another means of sending and receiving digital communication. HFDL augments existing VHF and satellite communications (SATCOM) (i.e., CPDLC and ADS-C) data link communication systems. A subnetwork of 15 HFDL ground stations extends worldwide communication coverage beyond that of VHF data link communication subnetworks.
2.17.1 HFDL Applications. HFDL subnetwork provides communication to both ATSU and AOC in oceanic and remote continental airspace and can be used for:
1. Non-SATCOM equipped aircraft with a long-range, cost-effective data link communication capability,
2. Data link communication in polar regions where geostationary satellite connections may not exist or be degraded, and
3. A back-up means of data link communication for SATCOM (CPDLC and ADS-C) equipped aircraft.
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2.17.2 Ionosphere HF Disturbance and Reliability. HF is subject to temporary signal distortion due to changes in the ionosphere layer shape and density. Because of multiple HFDL ground stations, ionosphere disturbances are less frequent than in the early days of HF voice. Modern aircraft HFDL systems automatically search for the best available frequency from all HFDL operational ground station frequencies. Once a suitable frequency is found, the aircraft establishes a connection by sending a logon/notification message to the ground station. A logon/notification confirmation uplink is established enabling the pilot to send data.
Note: Monitoring data have shown that HFDL does not meet RCP 240/RSP 180.
2.18 Future U.S. Domestic Airspace Data Link Communication Services. Figure 2-12 depicts future plans for data link communication services. Though this planning diagram is subject to change, it generally provides a preview of expanding data link services in the next few years. This is added to the AC to enable operators planning upgrades in pace with future technology and upcoming data link communication services.
Figure 2-12. Data Communication Services Strategy 14 18 20 22 24 26 28 30 Controller-Pilot Data Link (CPDLC) Departure Clearances (DCL) Segment 1 Phase 1
- Tower Service Deployment to 55 Towers Complete - DEC 2016 (2½ years ahead of schedule) Transfer of Communications Segment 1 Phase 2 Initial Check-In
- En Route En Route Altimeter Settings Altitudes PLANNED FOR Services Initial Speeds (Limited) ALL 20 ARTCCS Baselined Services Crossing Restrictions (Limited) May 2012 Airborne Reroutes / Go Button Controller Initiated Reroutes (Limited) Direct-to-Fix (Initial) Baselined Controller Initiated Routes (Full) October 2014 Crossing Restrictions (Full) Direct-to-Fix (Full) PLANNED FOR Baselined En Route Full Advisory Messages ALL 20 ARTCCs August 2016 Services Holding Instructions Speeds (Full) Deferred Full Stuck Microphone Adapted Arrivals Services Beacon Codes Segment 2 Dynamic RNP
- Advanced Services Formulation In Budget 4D Trajectories (4DTRAD) Advanced Interval Management Tailored Arrivals Avionics D-TAXI FANS 1/A ATN/IPS and FANS 1/A Ground System Future Air Navigation System (FANS)
ATN/IPS 2-29
2.19 Data Communication Services Strategy. Segment 1 in Figure 2-12 consists of two phases.
2.19.1 Tower Services and En Route Services. Segment 1, Phase 2 (S1P2) services will be delivered in two stages, “initial” services and “full” services. S1P2 en route services are expected to begin in 2019 and are planned to leverage existing Phase 1 FANS 1/A aircraft and expand Phase 1 infrastructure to deliver CPDLC services in the U.S. domestic en route airspace. Listed below are en route initial and full services:
1. En Route Initial Services. The initial services in S1P2 will include the following:
• Transfer of communications,
• Initial check-in,
• Altimeter settings,
• Altitudes,
• Speed (limited),
• Crossing Restrictions (limited),
• Airborne reroutes/go button,
• Controller initiated reroutes (limited), and
• Direct-to-fix (initial).
2. En Route Full Services. With the continuation of S1P2, en route full services will include (see the following paragraphs for descriptions of some initial and full service features):
• Controller initiated routes,
• Crossing restrictions,
• Direct-to-fix,
• Advisory messages, and
• Holding instructions.
Note: The full services of speed, stuck microphone, adapted arrivals, and beacon codes are deferred until further notice.
2.19.2 Speeds.
1. Initial Services. The controller can issue UM61 CROSS (position) AT AND MAINTAIN (altitude) AT (speed).
2. Full Services (Deferred). The controller will be able to:
• Issue speed clearance providing the pilot with instructions to maintain a speed in Mach number or indicated airspeed, 2-30
• Assign speeds of greater than or less than specific values, and
• Instruct the pilot to resume normal speed or to maintain present speed. The pilot will be able to request a speed clearance.
2.19.3 Crossing Restrictions. Initially, the controller will be able to use two crossing restriction message elements to instruct the pilot to cross a specific fix at a specific altitude and, if desired, at a specific speed. With full service, the controller will have considerably more flexibility in composing crossing restriction clearances. For example, the controller will be able to clear an aircraft to cross a specific fix at a specific time and have the option of entering a crossing restriction.
2.19.4 Routes. Initially, the pilot will be able to DM22 REQUEST DIRECT TO (position).
The controller will be able to issue route clearances, such as UM74 PROCEED DIRECT TO (position), UM79 CLEARED TO (position) VIA (route clearance), UM80 CLEARED (route clearance), and UM83 AT (position) CLEARED (route clearance). With full service, the controller’s workstation will be enhanced to support entry from the Radar (R) and Radar Associate (RA) positions and permit entry of route offsets with additional message elements.
2.19.5 Advisory. Air Traffic personnel issue advisory messages to aircraft on a routine basis.
Examples include dynamic airport information (runway closures, runway visual range, braking action, etc.), convective significant meteorological information (SIGMET), Central Weather Advisories (CWA), Pilot Weather Reports (PIREP), weather displayed on the controller’s scope, and current ride reports. CPDLC will allow the controller to send a limited set of advisory messages to the aircraft on a case-by-case basis or to all aircraft with which the controller has a CPDLC connection. Advisory messages such as SIGMETs and CWAs, which must be broadcast to all aircraft on frequency, will still need to be verbally broadcast in a mixed equipage environment. However, advisory messages that are issued to individual aircraft, such as dynamic airport information, displayed weather, PIREPS, and current ride reports are excellent candidates for automating. S1P2 CPDLC services will only support ride reports and free text messages created at the sector. The messages will be provided to the controller to send to the appropriate aircraft. In addition to freeing the controller from verbally delivering the advisory, CPDLC also allows positive confirmation that affected aircraft have received the information.
2.19.6 Holding Instructions. The controller may be directed to hold all arrivals for a particular airport. With full service, the controller will be able to send a CPDLC message UM91 HOLD AT (position) MAINTAIN (altitude) INBOUND TRACK (degrees) (direction) TURN LEG TIME (leg type).
2.19.7 Stuck Microphone (Deferred). With full service, the controller will be able to instruct the pilot to check their microphones.
2.19.8 Adapted Arrivals (Deferred).With full service, the controller and pilot will be able to use CPDLC to execute adapted arrival procedure. The adapted procedure contains both lateral and vertical aircraft maneuvers and provides greater efficiency for users.
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