Future Air Navigation System (FANS) Introduction Future Air Navigation System (FANS) is a oceanic airspace much in the same manner concept that was developed by the as ground-based radar does today over International Civil Aviation Organization land. (ICAO) in partnership with Boeing, Airbus, Honeywell and others in the air transport FANS routes have expanded mightily from industry to allow more aircraft to safely and the first North America - South Pacific routes efficiently utilize a given volume of airspace. in 1996. Today there are over 34 Flight Today FANS is used primarily in the oceanic Information Regions (FIRs) and Upper regions taking advantage of both satellite Information Regions (UIRs) around the communication and satellite navigation to globe supporting ATC surveillance (ADS-A) effectively create a virtual radar environment and Controller Pilot Data Link for safe passage of aircraft. FANS plays a Communication (CPDLC), providing FANS key role in supporting many of the evolving coverage worldwide (Figure 1). This CNS/ATM (Communication, Navigation, expanded coverage gives airliners and long- Surveillance / Air Traffic Management) range business jets the option to select strategies and mandates – an evolution that direct routes over many of the highly has been underway for more than ten years. traveled oceanic regions (Atlantic and Today, FANS-1 is the standard used on Pacific) and utilize FANS procedures Boeing aircraft while the Airbus standard is globally. Polar routes have also been known as FANS-A. Both are considered established that maintain FANS continuity first generation FANS architectures. Second when out of radar coverage. When generation FANS will be discussed under comparing the differences of today’s the FANS Evolution paragraph. traditional voice reporting system to FANS, the obvious advantage is being able to place The first FANS routes made their debut in more aircraft in the same airspace and do it the Pacific in early 1996 and were originally safely. The uncertainties of voice reporting flown by three airlines with the Boeing 747- and the delay associated with HF radio 400. These B-747 FANS 1 equipped aircraft require the air traffic controller to allow a use Global Positioning System (GPS) tremendous amount of airspace between satellites and Inertial Reference Systems each airplane, typically 100 nm laterally and (IRS) to fix their position and an on-board 120 nm longitudinally. With FANS and the Honeywell Flight Management System recent Required Navigation Performance (FMS) to manage the navigation solution (RNP) mandates, air traffic controllers can and flow of information. The position of the safely and significantly reduce those aircraft is then transmitted through a separation distances and allow more communications router and sent to Air flexibility for the FANS-equipped aircraft. Traffic Control (ATC) via either VHF or SATCOM. The FANS standard mandates the use of INMARSAT SATCOM when out of VHF range. This Communication (VHF or SATCOM), Navigation (GPS / FMS) and automatic dependant Surveillance (ADS-A) concept enables ATC to create a clear picture of the traffic in a given block of 1 FANS 1/A U.S. airspace boundary FANS 1/A FANS 1/A Graphic courtesy of The Boeing Company Figure 1 FANS Components The term FANS encompasses a set of the FIR). ADS contracts are established by defined software features required within the the ground station following a logon from an FMS. Changes within these features have aircraft. Although ADS and CPDLC are improved since 1996 based on thousands of separate applications, they both use the hours of pilot and ATC usage to ensure all same logon from the aircraft for their own aspects of CNS/ATM are satisfied safely purposes. ADS-A will also maintain and efficiently. The current FANS features surveillance continuity through automatic Honeywell develops for its line of FM handover across FIR boundaries. systems are: CPDLC – Controller / Pilot Data Link AFN – Air Traffic Services (ATS) Facilities Communication: CPDLC is the data link Notification: AFN contains the protocol software algorithm within the FMS that within the FMS for the aircraft to log-on to a enables two-way communication between ground facility and establish ADS-A or C the cockpit and ATC. It contains the set of surveillance. AFN also provides a link predefined text messages for clearances, between providers to enable automatic requests and routine message traffic. The handoff between regions. current FANS CPDLC is designed to use the ACARS network much in the same manner ADS-A or ADS-C – Automatic Dependant that AOC (Airline Operational Control) is Surveillance-Addressed or Automatic used today. But rather than route message Dependant Surveillance-Contract: ADS-A/C traffic to an airline operational center, the contains the software algorithms to transmit CPDLC is routed from the cockpit to ATC the position of the aircraft (either via based on handling instructions within the SATCOM or VHF) every one to five minutes aircraft CMU (Communications Management to an ATC listening station (typically within Unit). 2 capability for takeoff-weight-limited flights. RNP – Required Navigation Performance: If FANS were implemented on business jets, RNP containment is now required in certain operators would be able to take advantage oceanic regions throughout the globe. RNP of several needed improvements: has been a component of FANS since inception. Global Position System (GPS) 1. Reduced separation between and Inertial Reference System (IRS) airplanes combined with FMS provide compliance with 2. More efficient route changes RNP mandates now in effect. RNP 4 and 10 3. Satellite communication (4 and 10 NM lateral contain containment) 4. No altitude loss when crossing are typical in oceanic regions. Actual RNP tracks is continually monitored by the flight crew 5. More direct routings and they are notified of any exceedance. 6. Reduced user charges for using the The flight management systems developed FANS infrastructure by Honeywell meet all FANS-related RNP mandates now in effect. Reduced Separation Between Airplanes RTA – Required Time of Arrival: RTA gives In non-FANS procedural airplane the flight crew the ability to assign a time separation, errors in navigation and potential constraint to a waypoint, allowing the aircraft errors in voice communication between the to cross a latitude or longitude at a specified flight crew and air traffic control are time. The cruise speed is automatically considered when determining the necessary adjusted by the autothrottle to achieve the airspace separation between airplanes. The RTA plus or minus 30 seconds. If the RTA uncertainties of traditional voice position is not possible, the flight crew is notified with reporting and the delay associated with a visual alert. high-frequency relayed voice communications (10 to 20 minutes to make Flight Plan Updates – The FMS will have the a high-frequency voice position report) capability to update the flight plan based on require the air traffic controller, in the pre- revised clearances received by ATC via RNP / FANS era, to allow a tremendous CPDLC. The flight crew would acknowledge amount of airspace between each airplane – the clearance and the active flight plan typically 100 nm laterally and 120 nm would be updated. longitudinally. This computes to 48,000 square miles of airspace to protect on Benefits to Business Jets airplane and means that airplanes often operate at less-than-optimum altitudes and With the exception of a small number of speeds. Boeing Business Jets (BBJs), the business jet community as a whole has not taken In contrast, through a satellite data link, advantage of the growing FANS airplanes equipped with FANS can transmit infrastructure. The super long range automatic surveillance reports with actual business jet aircraft, predominantly the position and intent information at least every Gulfstreams, Falcons and Bombardier one to five minutes. The position is based family, have yet to certify a FANS system on the highly accurate Global Positioning despite having most of the avionics System (GPS). Digital data communication hardware (such as SATCOM, GPS and between the flight crew and the air traffic FMS) already onboard. The business case controller drastically reduces the possibility to install FANS systems on these long range of error and allows greatly reduced airplane jets is currently being made around a set of separations. The combination of benefits and paybacks. The airlines have improvements in the communication, reaped these benefits for many years and navigation and surveillance allows business jets are benefactors of the authorities to reduce required separation pioneers of the early FANS routes. The distances between airplanes, which in turn benefits offered by FANS include reduced allow airplanes to fly at their optimum fuel burn and flight time through more altitude and burn less fuel. efficient routing and increased payload 3 More Efficient Route Changes Oceanic operations currently are based on as 4,000 feet below optimum altitude. But if weather data that are up to twelve hours old. the air traffic controller has timely By using the satellite data link, the latest surveillance data via FANS from both weather from a variety of weather services is airplanes, including projected intent, and the transmitted to the airplane while en route. airplanes are able to control their speeds so Flight crews can then use these data to that they reach crossing points at a given develop optimized