55TH ANNUAL CONFERENCE, Las Vegas, USA, 14-18 March 2016
WP No. 164
From RNAV Visual Approaches to Visual Guided Approaches Supplemented by RNAV
Presented by TOC
This working paper describes the introduction of Visual Guided Approaches supplemented by RNAV, formerly called RNAV Visual approaches, in a number of airports around the world before the publication of any relevant documentation on the subject by ICAO. This lack of regulatory framework has resulted in different implementations of those approaches, with the consequent negative impact they can have on the safety of the operations due to the non- standard procedures used around the world. The paper highlights those issues as well as the recent work within ICAO to standardise the design and implementation of that type of approach, work in which IFACTA has been actively involved.
1.1 The use of aRea NAVigation (RNAV) systems in all phases of flight has increased considerably in recent years as a means of optimising the existing airspace and reducing the dependency on ground-based navigational equipment; both enablers of the greater flight efficiency required for present and future ATM operations.
1.2 In the approach environment, RNAV approaches have been available for a number of years thanks to the availability of high performance RNAV systems and the use of Global Navigation Satellite Systems (GNSSs). There are different types of RNAV approaches depending on the level of horizontal and vertical guidance provided. This working paper will concentrate on one particular type: the RNAV Visual approach or, the term recently adopted by ICAO, Visual Guided Approach supplemented by RNAV, i.e. VGA (RNAV), which is a particular type of VGA. This type of approach was initially proposed by the USA Federal Aviation Administration (FAA) back in 2010  and is currently in use in a number of international airports.
1.3 However, ICAO has not yet published any Standards and Recommended Practices (SARPs). In 2013, a Flight Operations Panel working document was made available making reference to the concept of RNAV Visual approaches , but it was only in the last 12 months that ICAO started drafting a Concept of Operations (CONOPS) document for VGAs with the aim of harmonising the design of those procedures . Nevertheless, until that document is complete, the lack of worldwide standardisation can have a negative effect on the safety of the operations at those airports where such VGAs (RNAV) are available.
1.4 This paper will look at the advantages and disadvantages of VGAs (RNAV) from an ATM perspective and at what needs to be done to address the issues mentioned in the previous paragraph. It will try to identify the best way forward to ensure that VGAs (RNAV) can be safely flown by crews and can be safely integrated in the ATM environment by ATC and compare that to the work being carried out by ICAO.
Visual Guided Approaches Supplemented by RNAV
2.1 A VGA supplemented by RNAV or VGA (RNAV) is, in simple terms, a combination of an RNAV approach and a visual approach. An RNAV approach is the term commonly used to refer to an approach procedure which complies with ICAO Performance Based Navigation (PBN) specifications for Required Navigation Performance APproaCH (RNP APCH) . An RNAV approach is described by a series of waypoints, legs, speeds and altitude constraints stored in the on-board navigation database. On the other hand, a visual approach is an approach by an IFR flight when either part or all of an instrument approach procedure is not completed and the approach is executed in visual reference to terrain .
2.2 RNAV approaches are divided into Non-Precision Approaches (NPAs) and Approach Procedures with Vertical Guidance (APV) . RNAV NPAs are further divided into Lateral NAVigation (LNAV), where lateral navigation guidance is provided by GNSS, and Localiser Performance (LP), where lateral navigation guidance is provided by GNSS and a Satellite Based Augmentation System (SBAS), such as the European Geostationary Navigation Overlay System (EGNOS). At the same time, RNAV APV are divided into LNAV/Vertical NAV, i.e. LNAV/VNAV, which combines LNAV and vertical guidance provided by a barometric altimeter, and Localiser Performance with Vertical Guidance (LPV), where lateral and vertical guidance is provided by GNSS and SBAS. There is one other type of RNAV approach, RNP Authorisation Required (AR) APCH , which requires additional levels of scrutiny, control and authorisation but which is beyond the scope of this paper. Figure 1 shows a basic diagram of the different types of RNP APCH approaches.
2.3 VGAs (RNAV) combine a lateral flight path via RNAV waypoints and a final visual approach segment. The aircraft effectively navigates using the RNAV system, but the position is monitored by visual reference to the ground. As such, flying a VGA (RNAV) can be seen as flying two simultaneous approaches, an instrument approach, because crews must navigate via the Flight Management System (FMS) to maintain the published track, and a visual approach, where the vertical position is monitored by visual reference to the ground, obstacles and other traffic .
2.4 The main advantage of VGAs (RNAV) is the greater flexibility they provide when designing their procedures compared to other approaches. In their simplest form, they can be based on a number of waypoints with altitude and speed restrictions, emulating existing visual approach paths, which is particularly relevant for airports that do not have ground based approach and landing systems. In addition, VGAs (RNAV) can be designed to avoid noise sensitive areas and reduce the overall environmental impact compared to other approaches. Finally, by providing predictable flight paths and a visual approach, it is claimed they can potentially reduce air traffic controllers’ workload.
2.5 As examples of that type of approach, the VGA (RNAV) charts for runway 30 at Ben Gurion International Airport at Tel Aviv (Israel) and runway 05 at Bordeaux-Mérignac International Airport at Bordeaux (France) are included in the Appendix (the terms Visual Approach with Prescribed RNAV Track and RNAV Visual are used on the charts, respectively). Using the information contained on those charts, we can identify the main features of that type of approach which, for simplicity, have been grouped in the following 5 categories:
a) Navigational Requirements: the aircraft must comply with the navigation requirements stated on the chart. In the case of the VGA (RNAV) for runway 30 at Ben Gurion International Airport, only RNAV 1 is required, while the VGA (RNAV) for runway 05 at Bordeaux-Mérignac requires GNSS (RNAV 1) and Radius to Fix (RF) Leg. An RF Leg is a curved path between two waypoints, defined by a radius and a centre fix. It should be noted that, strictly speaking, RNAV 1 is not a navigation specification for RNAV approaches since, in principle, it can be used for the initial and intermediate approach but not for the final approach .
b) Prescribed Track Compliance and Altitude and Speed Restrictions: the prescribed track must be maintained throughout the entire approach. At or above altitude and maximum speed restrictions are shown at various waypoints during the approach. Beyond the point where the visual approach segment starts, no altitude restrictions apply and terrain and obstacle clearance is to be achieved visually.
c) Weather Minima: the weather minima required to fly VGAs (RNAV) are only based on cloud ceiling and visibility with no associated Minimum Descent Altitude (MDA) or Minimum Descent Height (MDH). In both examples, the cloud ceiling is such that the crew can acquire the required visual reference before the start of the final visual approach segment: surface in sight for runway 30 at Ben Gurion International Airport and airport in sight for runway 05 at Bordeaux-Mérignac International Airport.
d) Go Around/Missed Approach: go around procedures are available on both charts. However, the go around procedure for the VGA (RNAV) for runway 05 at Bordeaux- Mérignac International Airport is the same as the missed approach procedure for the RNAV approach to the same runway.
e) Naming Conventions: the naming conventions used on each chart are different, reinforcing the need for standardisation. The VGA (RNAV) for runway 30 at Ben Gurion International Airport uses only the name of the waypoint where the visual approach segment starts, i.e. “SOSOT APPROACH RWY 30”, while the VGA (RNAV) for runway 05 at Bordeaux-Mérignac International Airport adds the words “RNAV Visual”, i.e. “RNAV VISUAL SOGBO RWY 05”.
Current Standards and Regulations
2.6 The concept of VGAs, although with a different term, was initially introduced by the USA FAA in March 2010 with the publication of Order 8260.55 . The order provides instructions and guidance to aviation and ATM organisations on how to assist aircraft operators with the development and operational approval to use special RNAV Visual Flight Procedures (RVFPs). The motivation was to reduce the number of unstable approaches due to excessive rates of descent during the approach, in particular when flying visual approaches. Since many of those aircraft are equipped with RNAV systems, the FAA believed that RVFPs could alleviate the problem by introducing predictable flight path which could reduce air traffic communications and enhance safety. The instructions in Order 8260.55 linked to the main features identified in 2.5 are :
a) RVFPs are to be used only by pilots of aircraft equipped with an approved RNAV system, which uses either Distance Measuring Equipment (DME)/DME/Inertial Reference Unit (IRU) and/or GPS sensor inputs. FAA considers RVFPs “special procedures” and, as such, they have to be approved by the FAA for specific operators.
b) RVFP must emulate existing visual approach flight paths, including all normal operational and/or desired altitude and speed restrictions. The operator must determine the descent gradients and turn angles of the RVFP in coordination with the local ATC facility and should adhere to FAA RNAV design criteria. Although simulator or aircraft must be used to validate the procedure design, no flight inspection by the FAA is required. In addition, a runway served by an RFVP should be equipped with a visual or electronic visual guidance system. The vertical path provided in the final segment of the RVFP must be coincident with or steeper than the guidance provided by either the visual or electronic system.
c) The ceiling and visibility values required for the RVFP must equal or exceed the requirements for visual approach operations.
d) Given the final visual approach segment, no missed approach procedure is required but no go around instructions are published either.
e) The RVFP naming convention is based on the type of procedure and runway served, for example “RNAV VISUAL RWY 29”. The RVFP must be coded in the RNAV system database and be retrievable by name.
2.7 In 2013, the Colombian Civil Aviation Authority (Aerocivil) published Aeronautical Information Circular (AIC) A08/13 providing standard guidance for the development and use of the concept of RVFPs . The AIC uses Order 8260.55 as a baseline but it introduces a number of specific changes and it also allows the use of ICAO guidelines during procedure design. The guidelines in AIC A08/13 relevant to the main features in 2.5 are :
a) Only operators already authorised by Aerocivil to perform GNSS based RNP APCH operations can seek operational approval to use RVFPs.
b) The guidelines with respect to 2.5 b) are the same as in Order 8260.55, with the exception of three important differences:
1. ICAO design criteria can also be used in addition to FAA design criteria throughout the entire RVFP design.
2. Flight inspection by Aerocivil is required.
3. The RVFPs, even though visual in nature, shall provide terrain and obstacle clearance along the prescribed track.
c) The ceiling and visibility values required for the RVFP are the same as the requirements for visual approach operations.
d) Go around instructions must be provided. It also states that a MDA/H must be published to allow the flight crew to identify the altitude or height limit at which to disconnect the autopilot, but no more details are given.
e) Naming conventions are based on the ICAO criteria for the designation of normalised arrivals and departures, for example “RNAV VISUAL WAYPT RWY 02”.
2.8 From the two examples above, it can be observed that important differences exist between them, even though Aerocivil’s document is based on the FAA Order. This shows a distinct lack of standardisation when developing concepts, procedures and charts for VGA (RNAV) procedures that are being flown in a number of countries already. There are no existing criteria within ICAO Procedures for Air Navigation Services (PANS-OPS) to ensure consistent application of the VGA (RNAV) concept, resulting in various implementations of VGAs (RNAV) with the negative impact it can have on the safety of the operations .
2.9 In 2014, the Direction des Services de la Navigation Aérienne (DSNA) together with Air France set up a dedicated working group to trial the VGA (RNAV) into Bordeaux- Mérignac International Airport included in the Appendix. The Aeronautical Information Publication (AIP) SUPplement (SUP) 083/15 published to describe that trial also identified that there was an absence of specific regulations for these procedures within French and ICAO regulations . As such, the aim of the group was to gather lessons learnt from an operational evaluation in order to feed the experience back to the development of harmonised regulation and guidance on VGAs. In 2015, the evaluation of VGAs (RNAV) was extended to Nice Cote d’Azur International Airport .
2.10 In that time, the only relevant documentation from ICAO was a working paper of the Operations Panel from December 2013, which looks at the “Concept of Operations for RNAV Visual Approaches” . The aim of the paper is to propose a standard concept of operations for the application of RNAV Visual approaches so that standardised design criteria and charting methodologies can be applied, in order to remove the type of inconsistencies highlighted in the two examples above. Using the RNAV Visual term in , the specific points with regards to the main features identified in 2.5 are:
a) The RNAV Visual approach procedure chart will indicate the minimum navigation specification required to fly the procedure.
b) All RNAV Visual approaches will be designed following standard criteria.
c) Operating weather conditions shall be clearly depicted on the chart.
d) The course of action in case of loss of visual contact or inability to complete the approach to landing needs to be included with the procedure.
e) The chart identification of the RNAV Visual approach procedure will be consistent with and comply with existing naming conventions in . However, it will be differentiable from an instrument approach procedure.
These guidelines are just generic clauses that are to be taken into account as part of any standardisation process within ICAO. This work has now been superseded by the work of the Flight Operations Panel (FLTOPSP) , which is described later in this paper.
Considerations for Pilots and Air Traffic Controllers
2.11 The introduction of new operational procedures in ATM is, in most cases, driven by a requirement to improve current operations with regards to, for example, safety or efficiency. As such, VGAs (RNAV) should be introduced when a clear operational benefit has been identified, as recommended by ICAO . In the case of the FAA, the main motivation behind RVFPs was to reduce the number of unstable visual approaches. However, IFALPA has reported that the opposite is often the case due to the nature of those approaches . That indicates that a complete analysis of the operational side-effects of VGAs (RNAV) has not been carried out. Instead, stakeholders have given priority to the fact that VGAs (RNAV) offer a great deal of flexibility. They can be designed using existing visual approaches as the starting point and defining an RNAV lateral flightpath. Since they only provide lateral guidance, they do not need to fully comply with the ICAO requirements for PBN approaches.
2.12 VGAs (RNAV) are fundamentally visual approaches in spite of their lateral RNAV component. When flying visual approaches, pilots are responsible for separation from the preceding aircraft once in sight, provided it is also flying a visual approach, and from obstacle and terrain clearance, as specified by ICAO . However, there is a risk that the pilots might not be fully aware of the fact that they are flying a visual approach due to the following:
a) VGAs (RNAV) are promulgated using charts similar to instrument approach charts.
b) The lateral navigation is done from waypoint to waypoint, similar to how an instrument procedure is flown.
That potential lack of awareness can have serious safety implications. In order to avoid that, it is particularly important that pilots are fully aware of their roles and responsibilities with respect to separation and terrain and obstacle clearance. Likewise, air traffic controllers need to have the same awareness in order to provide the required level of service. The most effective way of achieving that is by promulgating precise and consistent information wherever VGAs (RNAV) are in use. Unfortunately, this paper shows that the reality is very different.
2.13 With regards to the separation of aircraft, the documents analysed in this paper do not address the issue appropriately:
a) The FAA document does not specify who is responsible for separation. It only states that when pilots accept an RVFP clearance, they also accept the requirements and responsibilities associated with a visual approach clearance . The document does not go into any more detail, it only cites visibility minimums and cloud clearances as examples of those requirements and responsibilities.
b) Aerocivil’s document only states that in the case of successive visual approaches, the separation will be maintained by ATC until the pilot of the following aircraft reports having the preceding aircraft in sight and can maintain the separation .
c) The DSNA document states that ATC is responsible for the separation between aircraft but it does not go into any more details .
The working paper from ICAO does not specifically provide a solution to the conflicting and incomplete information of the three cases above, but it implies that the separation of aircraft is the same as in the case of a visual approach .
2.14 With regards to terrain and obstacle clearance, we encounter the same issue:
a) The FAA document does not specify the responsibility for terrain and obstacle clearance .
b) Aerocivil’s document states that RVFP procedures, despite being visual procedures, shall provide terrain and obstacle clearance near the proposed trajectory .
c) The DSNA document does not specify the responsibility for terrain and obstacle clearance .
Again, the working paper from ICAO only implies that the responsibility for terrain and obstacle clearance is the same as in the case of a visual approach .
2.15 Pilots and air traffic controllers must be aware of the weather minima required to fly a VGA (RNAV) so that when a pilot requests or ATC offers a VGA (RNAV), that minima, in terms of cloud ceiling and visibility, can be assessed and complied with. ICAO, the FAA and Aerocivil all specify that the cloud ceiling and visibility must be at least the same as those required for a visual approach. In addition, pilots need to acquire the required visual references before they can be cleared for a VGA (RNAV). Both pilots and air traffic controllers must be aware of the required actions when a pilot has not acquired the required visual reference and the approach needs to be discontinued.
2.16 Another important aspect of a VGA (RNAV) is the required course of action if the approach cannot be completed. The terms go around and missed approach are both used in the documents analysed even though, strictly speaking, the term missed approach is normally used for instrument approaches. That fact and the conflicting information on the subject already presented in this paper show the lack of standardisation in such an important aspect of an approach. Again, pilots and air traffic controllers must be fully aware of the course of action when an approach cannot be completed, coordinating the required actions when go around/missed approach procedures are not specified, for example in the case of the USA .
2.17 A VGA (RNAV) is a combination of automated and manual methods of operation, two fundamentally different ways of flying an aircraft. Even though it was anticipated that such approach would reduce the pilot’s workload by being more predictable than a visual approach, it has not been always the case . The combination of flight path monitoring using onboard navigation aids and visual flying has often resulted in an increase in the pilot’s workload. During a visual approach a pilot spends about 90% of the time with the head up, looking out, and 10% of the time looking down at the instruments. On the other hand, the belief is that, during a VGA (RNAV), the pilot needs to spend about 75% of the time looking down at the instruments with only 25% of the time left to look out the cockpit window . Therefore, workload management by the pilot is crucial when flying a VGA (RNAV), since it is considered a visual approach but the majority of the time is spent looking down at the instruments, paradoxically.
2.18 Workload management by the air traffic controller is also of particular relevance. Although a visual approach is considered to reduce controller workload, the addition of an RNAV lateral flight path to create a VGA (RNAV) can potentially increase that workload. The current lack of VGA (RNAV) standardisation means that the controller might need to monitor the actions of the crew more closely compared to other approaches. Even though the procedure is fixed for that specific unit, crews might have flown VGA (RNAV) at other airports where the procedures are considerably different.
Recent ICAO Work
2.19 In the last 12 months, ICAO has been working actively to resolve the issues highlighted above, which have been caused by the lack of relevant ICAO documentation to support the standardisation of VGA (RNAV) procedures. At the second meeting of the Flight Operations Panel Working Group in May 2015, it was acknowledged that non-standard operational concepts, procedures and charting have taken place in the context of VGAs (RNAV) and that a regulatory framework was required . Using the phased-out terminology RNAV Visual, a number of basic assumptions were made in  to set the scope for the standardisation of such procedures, namely:
a) An RNAV Visual is primarily an ATM tool targeting safety, efficiency and environmental gains.
b) An RNAV Visual is an enhancement of the standard visual approach and will be developed only where a visual approach is already in us by ATC.
c) The RNAV Visual is incorporated into the terminal area procedures and is preceded by a suitable initial instrument segment.
d) When cleared for an RNAV Visual, the pilot will follow the coded RNAV path or inform ATC if not possible.
e) Traffic separation remains responsibility of ATC throughout the operation.
f) An RNAV Visual is not intended to be used in marginal weather conditions.
g) Consequently, RNAV Visual approaches can be seen as a new type of RNAV approach. This last point is particularly important, since it moves RNAV Visual approaches away from the concept of visual approaches, with the associated changes in their practical implementation and nomenclature.
2.20 In addition,  included details from the evaluation and analysis carried out in Nice about the possible implementation of VGA (RNAV) procedures at Nice Cote d’Azur International Airport , building on the experience at Bordeaux-Mérignac International Airport . The decision was made to investigate if that information could be used as an initial working document by the PBN Operations Sub-Group (PBN OPS SG), which had been already working on the possible use of aircraft’s RNAV capability in visual conditions . In the end, it was decided that the RNAV Visual work package would be assigned to the Air Traffic Management Procedure Harmonisation Sub-Group (ATMPH SG), part of the newly formed FLTOPSP. The ATMPH SG would coordinate the sharing of information when required with the ATM Operations Panel, the Instrument Flight Procedures Panel, the PBN Sub-Group and the Aeronautical Information Services to Aeronautical Information Management Study Group.
2.21 In October 2015, at the second meeting of the FLTOPSP, the ATMPH SG presented a working paper containing an initial draft of the CONOPS for VGAs . The aim of the document is to standardise the design and implementation of the so called charted visual approach procedures. Those procedures are already in widespread use worldwide, they require visual conditions in order to be initiated and are normally established for safety, efficiency or environmental reasons. The CONOPS groups all permutations of charted visual approach procedures under the term VGA:
a) VGA using ladmarks, i.e. VGA (Landmarks).
b) VGA supplemented by RNAV, i.e. VGA (RNAV).
c) Visual manoeuvring with prescribed track.
d) Visual manoeuvring with prescribed track supplemented by RNAV.
2.22 Concentrating on VGAs (RNAV),  includes two definitions which already specify some of the elements that must be present in those procedures:
a) VGA: a charted approach procedure requiring meteorological conditions, as published on the chart, to continue the approach after a published position. They are established at specific aerodromes for environmental/noise considerations or when necessary for safety and efficiency.
b) VGA (RNAV): a VGA approach procedure charted using RNAV waypoints and path terminators to describe the arrival route.
2.23 Looking at the main features of a VGA (RNAV) identified in 2.5, the CONOPS in , even though still a draft document, already resolves most of the inconsistencies encountered when comparing the different implementations of VGAs (RNAV).
a) Navigational Requirements: A PBN box on the VGA (RNAV) chart will indicate the aircraft requirements. RNP APCH certification is required while RF capability and vertical guidance are optional, depending on the procedure. RF legs are preferred to fly-by waypoints, since turn anticipation is not required. In that case, “RF required” means aircraft certified for RNP 1 with RF capability on Standard Instrument Departures and Standard Arrival Routes.
b) Prescribed Track Compliance and Altitude and Speed Restrictions: pilots must fly the published VGA (RNAV) route and, unless otherwise cleared by ATC, comply with charted mandatory altitude and speeds.
c) Weather Minima: the weather minima are based only on ceiling and visibility and they will be locally defined. There is no MDA or Decision Altitude (DA). The pilot shall have visual reference to the terrain as well as other visual references when considered relevant.
d) Go Around/Missed Approach: missed approach instructions when visual conditions are not sufficient at the VGA Decision Point (VGADP) shall be included on the charts. In addition, go around instructions if the VGA needs to be interrupted after the VGADP, shall also be included.
e) Naming Conventions: the proposed naming convention is VGA XX (RNAV), with XX being the runway. The intention is to differentiate the VGA from an uncharted visual approach and from an RNP instrument approach. In addition, the VGA (RNAV) must be coded in the aircraft RNAV system database and be retrievable by name.
2.24 Finally, from an ATM perspective,  also clarifies some of the points discussed in this paper. In particular, it states that ATC is responsible for separation from other aircraft, including preceding aircraft. It also states that the pilot will keep the terrain environment in sight after the VGADP and execute the approach with visual reference to the terrain. However, it does not explicitly state whether the pilot is responsible for terrain and obstacle clearance, although the altitudes published on the chart will provide adequate terrain and obstacle clearance.
2.25 It should be noted that IFATCA is actively involved in the development of the aforementioned CONOPS through the IFATCA representative to the FLTOPSP and with the support of TOC.
3.1 VGAs (RNAV) are currently in use at a number of international airports around the world. They combine the flexibility of a visual approach with the predictability of an RNAV lateral flight path. They are particularly useful at airports that do not have instrument approaches, since VGAs (RNAV) do not require equipment on the ground and they can be designed around noise and environmentally sensitive areas.
3.2 However, the lack of standards and the late publication of guidelines and drafting of CONOPS by ICAO have resulted in the existing heterogeneous set of VGA (RNAV) implementations. Those VGAs (RNAV) have not been checked against a common set of rules resulting in implementations that, at times, provide conflicting information to pilots. That has a negative impact on the safety of the operations at those airports.
3.3 Standards and recommended practices need to be developed and applied consistently across the world so that VGAs (RNAV) and their associated charts have the same level of standardisation as instrument approaches. Only then will the potential benefits of VGAs be materialised.
3.4 From a human factors point of view, it is necessary to ensure that pilots and air traffic controllers are fully aware of their roles and responsibilities with regards to VGAs (RNAV). Appropriate training, including workload management, needs to be designed so that VGAs (RNAV) can be flown and be integrated with the rest of air traffic safely and efficiently.
4.1 It is recommended that this paper is accepted as information material.
Last Update: October 1, 2020