PBN and RNAV concepts Rabat, 16/27-03-2015
Target: Learn basic concept on PBN and RNAV. NOT FOR COMMERCIAL PURPOSES 2
Concepts Part 1: PBN concept Part 2: RNAV, RNP Part 3: FTE (Flight Technical Error) Part 4: BV (Buffer Value) Part 5: Obstacles clearance area Part 6: Additional fixes NOT FOR COMMERCIAL PURPOSES 3
PAN OPS Reference PAN OPS Vol II Sixt Edition Part III Section 1 Chapter 1 NOT FOR COMMERCIAL PURPOSES 4
RNAV navigation RNAV can be defined as a method of navigation that permits aircraft operation on any desired course: within the coverage of station-referenced navigation signals, or within the limits of a self-contained system capability, or a combination of these. Estimated position is detremined using GNSS (GPS, EGNOS, ecc.), IRS, DME/DME The position amendment is obtained using available sensors FMS flight management is based on onboard database 5
PBN Concept Performance-based navigation (PBN) is defined as a type of area navigation (RNAV) in which the navigation performance requirements are prescribed in navigation specifications. A navigation specification is defined as a set of aircraft and aircrew requirements needed to support PBN operations within a defined airspace. There are two types of navigation specifications: a) RNAV specification. A navigation specification designation that does not include requirements for on-board performance monitoring and alerting. b) RNP specification. A navigation specification designation that includes requirements for on-board performance monitoring and alerting. NOT FOR COMMERCIAL PURPOSES 6
PBN Concept Performance-based navigation (PBN) is defined as a type of area navigation (RNAV) in which the minimum navigation performance requirements are prescribed in terms of: Accuracy: difference between real position of a/c and estimation of on board RNAV system NSE Navigation System error is the difference between the actual and desired position in fault free conditions TSE Total System error is the difference between the actual and desired flight path in fault free conditions Integrity: the ability to give timely warnings when the system cannot safely used Availability: of the total system Continuity: the ability of the navigation system to provide its service without interruption during operations NOT FOR COMMERCIAL PURPOSES 7
PBN PBN together with Communication, Surveillance and ATM are the keys concept to define the AIRSPACE concept. ELEMENTS: Air and ground side of the navigation infrastructure: Radioaid, IRS and GNSS Navigation specification (air side): Performance required in terms of RNAV capability and requirements in terms of crew training Navigation application: Procedure/Routes that can be designed in a n Airspace related to the 2 above elements. NOT FOR COMMERCIAL PURPOSES 8
Conventional vs PBN Conventional navigation BENEFITS System tested and reliable Easy monitoring of the infrastructure on the ground PBN Navigation Design flexibility BENEFITS Constant protection depending on the type of requirement (RNAV 1, RNAV 5, RNP ( 0.3 or lower) ) Rationalization of the ground radioaid Decreased flight time Best environmental efficiency DISADVANTAGES Rigid system (obligation to refer to the ground radioaids) Any airspace require an increased distance from reference radioaid DISADVANTAGES GPS constellation unmonitored Possibility to handle mixed traffic 9
Conventional Navigation vs RNAV Navigation - Example 10
Conventional Navigation vs RNAV Navigation - Example 11
Navigation Specifications and Applications PBN NOT FOR COMMERCIAL PURPOSES 12
RNAV vs RNP Both RNAV and RNP operations could be described in terms of navigation performance (e.g. accuracy), RNP operations can be identified by the capability of the on-board navigation system to monitor in real time the achieved navigation performance and to alert the operating crew when the specified minimum performance appropriate to a particular operation could not be met. This additional functionality provided by RNP allows the flight crew to intervene and to take appropriate mitigating action (e.g. a go-round), thereby allowing RNP operations to provide an additional level of safety and capability over RNAV operations. NOT FOR COMMERCIAL PURPOSES 13
Navigation specification per flight phase 14
Navigation specification per flight phase Notes 15
Flight Technical Error FTE The 95 per cent FTE values from which the design criteria for PBN applications have been derived are based upon the following formulae: For RNAV, FTE= 1 required navigation accuracy 2 For RNP 0.5, FTE= 1 RNP 2 For RNP 0.5, FTE=463M (0.25NM) 16
Buffer Value BV To address excursion beyond a 3σ values an additional buffer value based upon A/C characteristics and phase of flight is taken in account. 17
Area semi-width Protection Area ½ A/W= 1.5 XTT+BV XTT=cross track tolerance XTT is the 2σ cross-track tolerance value (known as TSE) Merging 30 going from larger to smaller area Merging 15 going from smaller to larger area ATT=along track tolerance More than one navaid type can be used on a procedure (e.g. DME/DME and GNSS for RNAV 1), the XTT, ATT and area semi-width shall be calculated for each specific navaid type and the obstacle clearance shall be based on the greater of these values. 18
Merging Area and ATT ATT= along track tolerance 19
Additional Waypoint on straight segment To allow implementation of specific constraints (e.g. a speed restriction, a change of altitude or a reporting point for ATC purposes) some waypoints may be added within a straight segment. Due to the flyability, pilot workload, navigation database size, etc., the following needs to be taken into account when add waypoints: Generally, no more than two additional waypoints should be specified within a straight segment (to be not considered for the calculation of the lateral protection area and are defined as fly-by waypoints) Altitude changes and speed restrictions shall only be applied when operational benefits are expected. 20
Step down fixes Criteria contained in Part I, Section 2, Chapter 2, 2.7.3, Stepdown fix and 2.7.4, Obstacle close to a final approach fix or stepdown fix relative to stepdown fixes apply. The SDF location shall not be considered for the calculation of the lateral protection area. 21
FTA and 15% plane 22
PBN «elements» RNAV and RNP Navigation Specifications FTE (Flight Technical Error) and BV (Buffer Value) Protection area Additional fixes (e.g. SDF) NOT FOR COMMERCIAL PURPOSES 23
NOT FOR COM MER CIAL