Study Remote/Virtual TWR from the Professional, Procedural and HF View

  • Home 2016 Study Remote/Virtual TWR from ....

Study Remote/Virtual TWR from the Professional, Procedural and HF View

55TH ANNUAL CONFERENCE, Las Vegas, USA, 14-18 March 2016

WP No. 313

Study Remote/Virtual TWR from the Professional, Procedural and HF View

Presented by PLC


The recent step-change in technological capabilities coupled with an increasing need to improve the efficiency of worldwide ATM has resulted in rapid progress in the areas of Remote and Virtual Towers. In this paper we will further explore the ongoing advances towards Remote Tower reality. Where last year’s TOC paper focused on the technical elements, we will be expanding this definition while considering the impact on a professional, procedural and Human Factors perspective.


1.1.  The exploration of Remote and Virtual Towers has accelerated significantly over the past two years. A significant driver behind this is the funding of exploratory work through the SESAR work stream within Europe. Work has also been ongoing to develop solutions in both the United States through the NextGen programme and Australia in Alice Springs.

1.2.  While cost reduction through operational efficiencies are a powerful driver behind the progression of the work, it is claimed that the technology also brings opportunities that could benefit the overall ATM structure giving additional safeguards to the aviation community and more resilience to airport operations.


2.1. Terminology

2.1.1.  The terminology surrounding this technology is still evolving, and previously agreed definitions require periodic updates. Take, for example the existing definition of a Remote Tower from TOC WP 92 “provision of an aerodrome control service (ACS) from a location other than the aerodrome at which the service is being provided.”

2.1.2.  Once these concepts are implemented, the provision of the service is most likely to be provided at a distance from the aerodrome however some of the projects currently under evaluation will, at least at the proof of concept phase, be physically located within the aerodrome boundary. While this may change as these projects mature, our definition should take these factors into account.

2.1.3. The agreed principle within the provision of a “Remote Tower” Service is that is it provided based upon the visual reproduction of an ‘out of the window’ perspective through camera(s) (which may be infrared) via video technology (

2.1.4. In a broader sense, as understanding of the options for implementation mature, it has become necessary to separate and define the different options for configuration. While Remote Towers are most commonly considered in relation to this topic, the SESAR solution also details the possibilities for Virtual Towers. This solution is used currently and under consideration in many facilities, particularly where the physically remote facility is intended as a contingency and full surveillance provision is not deemed necessary.

2.1.5.  In the ‘Virtual Tower’ facility the controllers are provided with an ‘augmented reality’ where computer generated images are supported by existing in-tower tools such as Surface Movement Radar (SMR). These may be supplemented with limited video based elements such as hot spot cameras highlighting critical areas of the aerodrome or virtual overhead representations of the locality in order to provide the controller with sufficient awareness to provide safe ATS.

2.1.6.  Whether a proposed solution is developed as a ‘Remote’ or ‘Virtual’ Tower will depend upon a variety of factors such as objective of the facility (temporary contingency, full provision of ATS, etc), traffic density, local environment and available technology. At this conceptual stage it is not possible to be too prescriptive about the requirements however regardless of the type of installation, the maintained safety of the operation and appropriate support for the ATCO task must be at least equivalent to the current operation.

2.1.7.  Within this document the term used to describe the full scope of all options is RVT – Remote and Virtual Towers.

2.2. Existing Policies

2.2.1.  The current IFACTA Policy for Remote and Virtual Towers from the Technical and Professional Manual states:

“Technology has created the possibility to provide aerodrome control service from a location other than the aerodrome itself. This new concept is being developed both in SESAR and NEXTGEN and is also being investigated in several other countries such as Australia and New Zealand.”


2.2.2.  IFATCA Policy is:

ATCOs shall not be required to provide a Remote and Virtual tower service for more than one aerodrome simultaneously.

Separation standards and procedures for Remote and Virtual Towers shall be developed or adapted and implemented based on a robust safety case and the demonstrated capabilities of the system.

Standards, procedures and guidance for Remote and Virtual Towers are required.


A separate IFATCA definition exists relating to “Visual observation and new aerodrome control tower concepts”. This highlights how a video or projected reproduction of an aerodrome does not constitute ‘Visual observation’ and that before any Aerodrome Control Service Concept can be endorsed by IFATCA:

The controller shall be provided with at least the same level of surveillance as currently provided by visual observation.

The introduction of Aerodrome Control Service Concepts shall be subject to full safety analysis and relevant safety levels shall be met.

Contingency procedures shall be in place.

Controllers shall be involved in the development of Aerodrome Control Service Concepts.


2.3. Current level of development

2.3.1.  While the discussions focus on future implementations, we must understand that the concept of a ‘Virtual Tower’ within the RVT concept is already approved as a safe method for the provision of Air Traffic Services (ATS). An example of a current application is the Virtual Contingency Facility (VCF) for London Heathrow Airport. This concept distances itself from discussions over line-of site and ‘Visual Observation’ concerns by mirroring the approval for operations under degraded visibility (due to the height of the VCR, procedures are agreed with the Regulator for operation above LVP traffic levels when the VCR is partially obscured by cloud but full Low Visibility Procedures do not exist). Instead of trying to recreate the physical live visual environment this facility utilises the advanced surface movement technology to operate at the same capacity as under ‘Tower in Cloud’ meteorological conditions, while operating from a physically remote facility.

2.3.2.  While many concepts are far from approval ANSPs worldwide are now taking a keen interest in the technological developments and considering where the technology could be of benefit to them.

2.3.3.  It is widely accepted that the first country that identified the potential and invested significantly in the possible technology was Sweden where Saab as the supplier and LFV as the Air Navigation Service Provider (ANSP) began exploratory work in 2006. Through Saab’s investment in the technology and more recently SESAR, the Swedish Transport Agency has now given approval to operate an Air Traffic Control Service for Örnsköldsvik Airport from the Sundsvall Remote Tower Center, 100km from the aerodrome (

2.3.4.  One key enabler for the recent acceleration of the concept development has been the SESAR programme as funding has been available for viable investigative projects with several European ANSPs making rapid progress from concept towards reality. Saab is helping to deliver projects with Avinor in Norway while DFS is making significant progress as it attempts to relocate Aerodrome Control Services from several smaller airports to a Remote Tower Centre (RTC) in Leipzig. Meanwhile Ireland is placing great emphasis in their intent to provide initially night time RT operations at Cork and Shannon Airports. Both the Netherlands and Italy are planning similar exploratory projects over the coming year.

2.3.5.  Outside of Europe Australia is progressing towards live trials for Alice Springs. In partnership with Saab, the ANSP is seeking to provide ATS from a newly constructed RTC 1500km from in Adelaide.

2.3.6.  Meanwhile in the United States as part of the NextGen Blended Skies program Leesburg Executive Airport in Virginia will begin a three month trial of Remote Tower operations in early 2015. Situated 5 miles from Washington Dulles International Airport, Leesburg is the busiest unit currently planning live trials, handling in excess of 100,000 movements per annum.

2.3.7.  There had also been exploratory work completed in New Zealand to provide Remote Tower facilities to low density airfields. However in January 2015, Airways NZ announced that it was suspending further development as it was not satisfied that the providers of the technology had sufficient evidence of the support technology’s capability.

2.3.8.  Manufacturer’s Perception

2.3.9.  The most advanced solutions currently being examined are perceived by the manufacturers to recreate the Visual Control Room (VCR) reality to sufficient degree to provide an equivalent level of safety to the aircraft operating in the vicinity of the aerodrome.

2.3.10.While some challenge if this can ever be fully recreated, the argument is made that by supplementing this image with additional technology based safety nets such as smart aircraft labelling and infringement monitoring, the overall safety provision is at least that of a conventional Tower facility.

2.4. Controller Perception

2.4.1.  At this stage of development most effort is focussed upon the technology rather than the individual. Regardless of the theoretical qualities of the technology, the difficulty is accurately determining how the change in interface affects the ability of the ATM operational staff to perform their function and then to analyse how this impact is proportioned. ATCOs are often resistant to change until they can be persuaded of an absolute assurance of suitability, and such a significant change in working environment will undoubtedly be unsettling.

2.4.2.  While much of this is entirely subjective, there are agreed methods by which Situation Awareness can be objectively assessed. During some of the most recent trials of Remote Tower concepts including the more advanced additional features it was demonstrated that a level of Situational Awareness equivalent to that of a conventional Tower were maintained and during adverse conditions actually surpassed those during normal operations. While this is an essential element of safe ATS it should be highlighted that, as yet, this has only been explored in very low density traffic environments.

2.4.3.  One area which raises obvious concerns is the ability of the controller to deal safely with situations of system failures both at the remote facility and within the remote system itself. While trials have not shown the management of such tasks as being significantly greater than at a conventional Tower, we are still at a conceptual level of development. It is also recognised that simulating non- standard or emergency situations can not replicate the full consequence including the psychological impact upon the individual.

2.4.4.  For remote locations where this is the norm this may be sufficient by itself and the technology may enable improvements to service provision for very low traffic density aerodromes where ATS provision is not economically viable.

2.4.5.  However before any implementation of the concept is extended to busier units a full assessment of the limitations of the new ATCO – Airport interface will be necessary to determine whether it offers a safe alternative to conventional ATS provision.

2.5. Training

2.5.1.  Feedback from the trials held so far indicated that the ATCOs involved were able to adapt their techniques to deliver an equivalent service from a Remote Tower facility however such a dramatic change in operating environment took some time to compensate for and more research is needed to determine how the differing environments affect the controlling task and that no new risk factors are created without appropriate mitigations.

2.5.2.  While much of the technology to support RVT in it’s infancy, in particular with regard to Remote Towers, IFATCA supports the ongoing trials to evaluate the concept while maintaining a strong focus on supporting the ATCO to perform their current role. The objective of the technology must be to allow the ATCO to perform their task in the same manner as if they were positioned within a VCR.

2.6. Multiple Towers

2.6.1.  Though certainly not the only reason, the single most powerful driver for ANSPs to introduce RVT Concepts is reduction of costs. This will undoubtedly lead to increasing pressure to extend the implementation of RVT Concepts onto multiple aerodromes within a very short timeframe. This is also listed as an objective of SESAR within it’s future ‘Multiple Tower Concept’ MTC (

2.6.2.  IFATCA does not object to ATCOs being licensed for the provision of ATS at more than one aerodrome.

2.6.3.  However, regardless of the level of traffic at each airfield, the cognitive requirements of task switching can not be performed while maintaining the same level of monitoring at more than one facility. While the concept of combined sectors is accepted in a radar environment, due to the nature of radar (eg. North is always North), this does not translate to the Aerodrome task where different runway orientations and local geography is unique to each airfield.

2.6.4.  This task switching inevitably results in a reduction in an ATCO’s ability to continuously monitor the traffic scenario at more than one location in contradiction to ICAO 4444 (Ed 15; This requires aerodrome controllers to “keep a continuous watch on all flight operations on and in the vicinity of an aerodrome as well as vehicles and personnel on the manoeuvring area”.

2.6.5.  The cognitive costs of task switching and the impact on task performance have been investigated in several psychological studies. These describe the concept of an ‘alternation cost’ which delays processing of even very similar tasks in different environments and the negative impact this can have on task performance (

2.6.6.  For this reason IFATCA remains strongly opposed to any development for RVT at multiple facilities.

2.7. Regulatory Framework

2.7.1.  Initial progress in this area was slow, however since the formation of SESAR the rate of progress has accelerated dramatically as the greater availability of funding has coincided with step-changes in the supporting technology.

2.7.2.  There is little evidence that regulatory authorities anticipated the pace of change and more importantly the potential requirement for regulatory oversight. This may have been based upon early assumptions, and ANSP desires, that little more than existing regulations would be required. However certain fundamental aspects of a remote facility are quite distinct. For example the management of non-standard or Emergency situations of both an Aerodrome and System nature are quite different when located away from the Aerodrome and due consideration must be given to external factors such as potential security threats, redundancy and contingency facilities.

2.7.3.  While progress has been made over the past 12 months, regulators must continue to focus on providing adequate guidance and assurance to ensure that any future implementations are fit for purpose and have been robustly assessed against appropriate safety requirements covering all elements of the new interface.

2.7.4.  From an ICAO perspective Aviation System Block Upgrades (ASBU) Module B1-81 includes a requirement to assess the concept with regard to the need to update ICAO regulations. The work to still in it’s infancy and subject to approval by the Air Navigation Commission, this may be completed as part of the Air Traffic Management Operations (ATMOPS) panel.

2.7.5. Following approval in April 2014 the EUROCAE WG-100 was initiated in July 2014 to initiate research into standardising elements of the RVT concept. As with many of the regulatory and technical aspects, this work is ongoing.


3.1.  The Remote Tower concept continues to attract attention from ANSPs throughout the world as a potential mechanism to provide ATS services more efficiently. Some of these applications will provide extended ATS where currently limited services are offered, others will be targeted at providing the current or more limited service at a lower cost.

3.2.  IFATCA is not opposed to the development of new technology to support the provision of ATS. However, regardless of the drivers behind each proposed application IFATCA, it should be recognised that the technology is still in it’s infancy and significant further work is needed to demonstrate that the technology can be developed to suitably support the ATCO.


4.1. This paper is accepted as information material.


Last Update: October 1, 2020  

January 24, 2020   718   Jean-Francois Lepage    2016    

Comments are closed.

  • Search Knowledgebase