PBN (Performance Based Navigation)
PBN (Performance Based Navigation)
1 PBN Basic Concepts
Performance Based Navigation (PBN) is a new operational concept proposed by the International Civil Aviation Organization (ICAO) based on the integration of regional navigation (RNAV) and required navigation performance (RNP) operational practices and technical standards from various countries. It combines advanced airborne aircraft equipment with satellite navigation and other advanced technologies, covering all flight phases from en-route, terminal areas, to approach and landing, providing a more precise and safe flight method and a more efficient air traffic management model. At the 36th Session of the Assembly in September 2007, ICAO formally required all Contracting States to fully transition from traditional ground-based navigation flight modes to PBN in a globally consistent and coordinated manner by 2016.
Traditional navigation utilizes signals received from ground navigation stations to achieve guidance for aircraft by flying towards or away from the station. Its routes and flight procedures are constrained by the layout and equipment types of ground navigation stations, and accuracy is limited; current operational concepts and technical means cannot solve the aforementioned problems. With the improvement of airborne equipment capabilities and the continuous development of satellite navigation and other advanced technologies, the International Civil Aviation Organization (ICAO) proposed the concept of “Performance Based Navigation (PBN)”. The introduction of PBN represents a shift in navigation methods from sensor-based navigation to performance-based navigation.
PBN has the following advantages over traditional procedures: • Precisely guide aircraft, improving flight operational safety; • Provide vertical guidance to implement continuous stable descent procedures, reducing the risk of Controlled Flight Into Terrain (CFIT); • Improve all-weather operations, ensuring safety for operations at airports with complex terrain; • Enable flexible and optimized flight paths, increasing aircraft payload, reducing flight time, and saving fuel.
The PBN prototype originated from the concepts of RNAV (Area Navigation) and RNP (Required Navigation Performance). The concept was proposed in the early 1990s when ICAO was researching and developing the Future Air Navigation System (FANS), initially applied to airspace management and air traffic separation allocation for transoceanic flights. With continuous innovation in airborne navigation technology, the definition and connotation of PBN are also constantly evolving. Based on the integration of existing research results, ICAO formally proposed the Performance Based Navigation concept in 2008, clarifying that RNAV and RNP are two different forms of PBN, and their scope of application has expanded to all stages of flight.
2 Navigation Specifications
PBN navigation specifications are a set of requirements for aircraft and crew required to support PBN operations in a specified airspace. There are currently two types of navigation specifications:
- RNP Specifications: Navigation specifications based on Area Navigation that require performance monitoring and alerting, designated with the prefix RNP, such as RNP 4 and RNP APCH.
- RNAV Specifications: Navigation specifications based on Area Navigation that do not require performance monitoring and alerting, designated with the prefix RNAV, such as RNAV 5 and RNAV 1.
3 Area Navigation (RNAV)
Area Navigation (RNAV) is a navigation method that has existed for a long time, allowing aircraft to fly along any desired flight path within the coverage of ground-based or satellite-based navigation equipment, within the working range of onboard autonomous navigation equipment, or under both conditions. Note: Area Navigation includes Performance Based Navigation as well as other Area Navigation operations that do not meet Performance Based Navigation regulations.
4 Status of PBN in Mainland China
By the end of 2013, there were 116 airports with PBN procedures in the Civil Aviation Administration of China (CAAC), accounting for 60% of the total civil aviation airports. Since June 27, 2013, RNAV 2/5 and RNP 4 operations have been implemented on airways such as A461.
- Jan 2010: Guangzhou Baiyun Airport - First to implement Area Navigation (RNAV) operations.
- Aug 2011: Sanya Phoenix Airport - First to implement RNP APCH operations.
- Jun 2009: Lhasa Gonggar Airport - First to implement RNP AR operations.
- Apr 2012: Jiuzhai Huanglong Airport - First to implement public RNP AR operations.
The RNP AR flight procedure at Jiuzhai Huanglong Airport reduced the scope and requirements for obstacle processing, saving approximately 30 million yuan in investment. The RNP AR operation at this airport effectively solved the problem of one-way takeoff and landing, helping airlines reduce operating costs by nearly 50 million yuan annually.
In the Southwest region, approval will no longer be granted to airlines without RNP capability to operate at six airports: Lhasa, Jiuzhai, Bangda, Linzhi, Ngari, and Shigatse. Eight airlines—including Air China, China Eastern, China Southern, Sichuan Airlines, Chongqing Airlines, Hainan Airlines, West Air, and Chengdu Airlines—implement RNP AR operations at Jiuzhai Airport.
The Central-South region is fully promoting RNP APCH operations at 8 airports, including Sanya. The Northwest region is steadily advancing the implementation of RNP APCH operations at 5 airports, including Yulin.
5 RNP AR
The RNP AR procedure is a procedure requiring special authorization: AR = Authority Required.
Advantages of RNP AR procedures:
- Compared to RNP APCH, it has a smaller protected area and more precise flight trajectories, thereby improving safety;
- Flexibly avoids high terrain, improving operational efficiency;
- Explores the potential of aircraft performance, pushing aircraft capabilities to the limit to solve actual limitation problems;
- Others.
Design basis for traditional procedures and RNP APCH procedures: ICAO DOC 8168, 9613, etc. There are a series of “unified” explicit specification requirements for all aircraft regarding turning, climbing, obstacle clearance, navigation, etc.
Design basis for RNP AR: Aircraft performance. Including navigation capabilities, flight management systems, airworthiness certification, etc., specific to every detail, making it more “personalized.”
RNP AR procedures include specific aircraft models and designated airports. Therefore, RNP AR procedures are often directly commissioned by airlines for operation of a specific aircraft type at a specific airport, belonging to “private customization.”
6 Approach Specifications
The Performance Based Navigation Manual provides two types of navigation specifications for approach operations: RNP Approach (RNP APCH) and Authorization Required RNP Approach (RNP AR APCH). The RNP APCH navigation specification is intended to meet the general operational requirements of RNP and allows aircraft with basic RNP capabilities to use this navigation specification without the need for operational authorization.
The other navigation specification, RNP AR APCH, allows for higher navigation performance levels, better addressing issues such as flying into airports in obstacle-rich environments, and can enhance Air Traffic Management (ATM). This navigation specification requires operators to meet additional requirements regarding aircraft and crew, and to obtain operational authorization from the national administration.
Radius to Fix (RF) Leg: When designing procedure tracks, using RF legs brings more flexibility. RF legs can appear in various stages of the procedure, including the final segment. If appropriate, the requirement for RF leg capability will be noted on the approach chart. Since the procedure design may or may not choose to use RF legs, the operator’s authorization must specifically state the capability to fly procedures containing RF legs.
RNP APCH can be defined as an RNP approach procedure requiring a Total System Error (TSE) of +/- 1 NM during the initial, intermediate, and missed approach segments (MAS), and a horizontal TSE of +/- 0.3 NM during the final approach segment.
RNP AR APCH can be defined as an RNP approach procedure requiring a horizontal TSE as low as +/- 0.1 NM on any segment of the approach procedure. RNP AR APCH procedures also require that a specific vertical accuracy be maintained, as described in Chapter 6, Volume II of the Performance Based Navigation Manual. The vertical reference for RNP AR procedures is the Landing Threshold Point (LTP). RNP AR APCH standards apply only to those aircraft and operators who comply with the other specified certification, approval, and training requirements. RNP AR APCH procedures are published only when operational safety can be maintained or improved, and significant operational benefits can be obtained. For RNP AR certification and approval requirements, see the Performance Based Navigation Manual. When using the standards contained in this manual, the RNP value represents the obstacle protection intensity associated with the RNP value. The RNP value is used to determine the area semi-width (in Nautical Miles) of the protected area associated with a segment covered by an instrument procedure.
http://www.caac.gov.cn/dev/fbs/xjsyy/201110/P020111010539500077595.pdf
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