Remote air traffic control towers: An application in Portugal

ABSTRACTWith continued growth in air traffic, airports worldwide are expanding their runway infrastructure. This leads to the problem of determining an appropriate location and height for an Air Traffic Control (ATC) tower that can provide the right vantage point for coordinating runway and taxiway movements. The challenge involves finding the right location and optimal height that can satisfy the visibility and obstruction constraints for a complex airport-airside environment with multiple runways and civil infrastructure under different weather conditions. This article formulates the ATC tower location and height problem as a Mixed-Integer-Programming (MIP) model while considering the visibility and obstruction constraints. Singapore Changi Airport's proposed third runway extension is used as a case study to determine the set of location and height of ATC Tower using the proposed approach. A visual analytic test is conducted in an ATC tower simulator for different tower locations and heights under varying visibility conditions.

Airports are one of the critical infrastructures that play an essential role in managing natural disasters through receiving or sending aid and supplies. Air traffic control (ATC) towers are an inseparable part of each airport as the performance of airports depends on the functionality of their ATC towers. Many ATC towers have been designed and constructed based on older versions of modern seismic codes in which seismic design has followed a force-based design approach. This study addresses the seismic vulnerability of three in-service ATC towers which have been designed and constructed according to a force-based design concept. The height of the towers ranges from 24 to 52 m. Fragility curves have been used for the seismic vulnerability study of these towers. For the derivation of seismic fragility curves, 45 earthquake records were selected and classified into low, medium and high classes based on their ratio of peak ground acceleration (PGA) to peak ground velocity (PGV). It was observed that records with a low PGA/PGV ratio imposed the highest level of damage to the towers. However, when towers were subjected to the records with a high PGA/PGV ratio, the damage intensity was not significant. Results indicated that the intensity of seismic-induced damage to the tallest tower was significantly more than that of the shortest tower. It was concluded that only the shortest tower could satisfy the expected seismic performance objectives.

Remote control of airports implies application of cameras to replace direct visual observation from airport control towers by projection of the airport and its traffic in a remote control centre. Surprisingly, hardly any literature can be found to list the required visual objects and phenomena for tower control, i.e. the visual cues that need to be seen for tower control. The composition and validation of the so-called visual cue list for tower control is the subject of this study. Tower controller task analysis was used to compose a ‘long-list’ of visual features. The long-list has been presented to a group of operational air traffic controllers to test the need and the circumstances to observe these visual cues. Our analysis shows that most of the visual cues are useful for operational tower control but are not strictly mandatory for applying the rules of the International Civil Aviation Organisation. The requirement for visual image resolution of remote tower control is the second subject of the paper. Our analysis leads to definition of a ‘shortlist’ of important safety-related visual objects and phenomena for tower control and the conclusion that state-of-the-art media are just able to provide the required image resolution for visual detection but not for recognition.

This research investigates how lightning strike–induced outages of airport infrastructure and facilities affect airport performance from an economic perspective, using Baltimore (Maryland)–Washington (D.C.) Thurgood Marshall International (BWI) Airport as a case study. On September 12, 2013, lightning struck within 300 m of the air traffic control (ATC) tower at BWI, causing injury and ATC tower and airport closures. The study findings reveal that the economic losses of the outage-related delays from that single event were almost five times higher than the ATC tower refurbishment that was planned, but unimplemented, in support of lightning protection, grounding, bonding, and shielding (LPGBS). The aim of this research is to support FAA's mission to better understand and quantify consequences of lightning strike–induced outages on airport performance. The research methodology and results can assist FAA in making sound decisions in support of LPGBS, and thereby help protect the National Airspace System infrastructure from lightning strikes and extreme weather and related delays.

Air Traffic Control (ATC) towers are among the most vital structures in each airport. Due to inadequate information regarding the seismic design and assessment of these types of structures, practicing engineers may refer to building codes. However, taking into account the special dynamic behavior of ATC towers, instructions and recommendations provided in building codes often do not comply with the required seismic performance levels of ATC towers. In this study, seismic behaviors of three in-service ATC towers with a dual concrete core lateral load resisting system were studied through pushover and incremental dynamic collapse analysis. Seismic design response factors of the reference towers were calculated. It was found that seismic design response factors adopted by the design code did not provide a uniform safety margin for all reference ATC towers. It was also observed that shorter towers have significantly higher response modification factors compared to taller towers. For the studied towers, a structural over-strength factor of 2.4 and a displacement amplification factor of 4 were obtained.

Airports face financial constraints in the use of services of air traffic control (ATC) towers. The remote air traffic control system (RATCS) is anticipated to be an economical and safe alternative to a control tower. RATCS is a concept intended to supply ATC to an airport by providing communication, navigation, and surveillance from a remote location. This study aims to gain insights about RATCS by conducting a review of existing studies, airport visits, discussions with RATCS technology providers, RATCS demonstration visits, and questionnaire surveys and interviews of controllers. A major inference from nontowered airport visits is that the introduction of RATCS will present many challenges such as pilot readiness to be supervised by RATCS, differences in local conditions, and significant limitations in available infrastructure. The knowledge gained through airport–demonstration visits and meetings with RATCS providers assisted in designing a questionnaire survey and interview. The number of surveys and interviews was limited; hence, conducting a comprehensive quantitative evaluation from responses was difficult. Nevertheless, controllers who participated in the study developed a consensus. The survey outcomes showed that controllers had concerns about RATCS functionality for communication or coordination between controllers and for ATC in high traffic conditions. The controllers provided favorable responses toward new features of RATCS, such as infrared cameras, high-definition monitors, target tracking functionality, and runway overlays. Potential advantages of RATCS anticipated by some controllers include systems with replay capabilities, situational awareness capabilities in low-visibility conditions, and surveillance capabilities of ground operations.

The remote tower system is a new mode of air traffic control operation that solves many prominent problems in civil aviation operations. The most important concern is the safety of the remote tower. Therefore, to effectively evaluate the safety of remote tower system operations, this paper discusses and analyzes the workload of controllers in remote towers from the perspective of human factors. Front-line controllers were selected as subjects to conduct control command under two control modes, traditional physical and remote tower. Heart rate variability and NASA-Task Load Index data were obtained from controllers and analyzed. The results showed that there were no significant differences in standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD) between adjacent NN intervals, percentage of successive RR intervals that differ by more than 50 ms (PNN50) indexes, and NASA-Task Load Index data between the two control modes. The SDNN index had a significant positive correlation with the RMSSD index. There was a significant positive correlation between the SDNN index and the PNN50 index. The RMSSD index was positively correlated with the PNN50 index. Compared with traditional physical tower control, controllers in this study had no extra workload increase when carrying out remote tower control. Based on the analysis of objective heart rate variability indexes and subjective workload estimates of controllers in this study, it can be preliminarily judged that the operational safety of remote towers appears to be comparable to that of traditional physical towers. Shen H, An Z, Lu T, Wang Y, Li W-C. Objective and subjective workload of remote and physical tower controllers. Aerosp Med Hum Perform. 2025; 96(6):485-489.

Assessment of Visual Cues by Tower Controllers, with Implications for a Remote Tower Control Centre

Air Traffic Control (ATC) towers play significant role in the functionality of each airport. In spite of having complex dynamic behavior and major role in mitigating post-earthquake problems, less attention has been paid to the seismic performance of these structures. Herein, seismic response of an existing ATC tower with a wall-frame structural system that has been designed and detailed according to a local building code was evaluated through the framework of performance-based seismic design. Results of this study indicated that the linear static and dynamic analyses used for the design of this tower were incapable of providing a safety margin for the required seismic performance levels especially when the tower was subjected to strong ground motions. It was concluded that, for seismic design of ATC towers practice engineers should refer to a more sophisticated seismic design approach (e.g., performance-based seismic design) which accounts for inelastic behavior of structural components in order to comply with the higher seismic performance objectives of ATC towers.

Air traffic control (ATC) towers are recognized as critical facilities, valuable in ensuring the operability of an airport not only in ordinary conditions but also during or following a seismic event. In the light of a limited body of literature produced so far focussing on dynamics and especially seismic vulnerability of ATC towers, the main goal of this work is to produce seismic fragility functions for two case study reinforced concrete towers featuring a core-type shaft. Two three-dimensional nonlinear models were firstly subjected to nonlinear static analyses, and then to nonlinear dynamic analyses within a multiple-stripe analysis framework, selecting the motions according to the Conditional Spectrum method. The fragility curves were derived with reference to three limit states and in terms of two different conditioning intensity measures, namely the spectral acceleration at the fundamental period and peak ground acceleration. A comparison with the few curves currently available for ATC towers provided reassurance on the robustness of the undertaken procedure. The obtained seismic fragilities may be used as typological curves within endeavors aiming at seismic risk assessment of critical infrastructures like airports. Lastly, an expeditious method to assess the functionality of a tower accounting for nonstructural elements was proposed.

: 78th Civil Engineer Group, Environmental Management Division (78 CEG/CEV) has conducted an Environmental Assessment (EA) to address the potential effects of construction and operation of a new Air Traffic Control Tower (ATCT) at Robins Air Force Base (AFB). The proposed new ATCT would modernize 78th Operations Support Squadron (78th OSS) air traffic control operations and equipment; provide additional space for required air traffic control personnel, equipment and functions; and generally provide a more optimal work environment for air traffic control personnel. The existing Control Tower building would no longer be needed.

The innovative concept of multiple remote tower operations (MRTO) can maximize cost savings by applying video panorama‐based remote tower working positions, which can facilitate fewer air traffic controllers (ATCO) to provide the air traffic services (ATS) function for more airports. Five subject‐matter experts, qualified remote tower ATCOs, participated in this research work by applying the human error template (HET) and comparing workload between physical tower operations and MRTO using NASA‐TLX (Task Load Index). The results demonstrate that augmented visualization provided sufficient technical support for a single ATCO to perform tasks originally designed to be performed by four ATCOs, however, the demands of the associated multiple tasks induced significant workload. There were significant differences in ATCOs’ mental demand, temporal demand, effort, and frustration between MRTO and physical tower operations. This innovative technology may induce human–computer interaction (HCI) issues that impact ATCO's perceived workload. This creates a need for further research on how to manage ATCO's workload in a multiple remote tower environment. This research work provided scientific evidence that MRTO can achieve the objectives of Single European Sky Air Traffic Management Research program. The findings can be applied to both ATCO training design and remote tower system design.

Traditionally, air traffic control towers have relied on controllers and flight information officers to visually monitor the airspace through tower windows to ensure safe air traffic management. However, issues pertaining to tower maintenance and staffing have emerged. These challenges have prompted the exploration of a new air traffic control paradigm, the Remote Digital Tower (RDT). The RDT system facilitates air traffic management operations remotely using technological advancements such as cameras, sensors, information devices, and networks, thereby obviating the need for on-site control towers.This project aims to facilitate the safe and efficient operation of the RDT system. It focuses on proposing designs for both software and hardware that are secure, intuitive, and effective for the system's use.The design emphasis is on creating user interface software that allows controllers to conduct air traffic control operations remotely and on developing the hardware of the control console for these operations. A design team, including former air traffic controllers, has been assembled to incorporate user perspectives and expert insights into the design process.The initial phase of the design process involved analyzing the operational tasks of traditional control towers, system functionalities, and user interactions. Subsequently, a prototype system was developed, featuring a 360° panoramic display and a control console. The control console's interface was simplified by consolidating various displays and keyboards into a single touch-panel display. Interviews with former controllers informed task analysis, which guided the design of the prototype system.The software's operational panel was designed based on the task analysis. The user interface design was conceptualized from the task design, considering the basic layout and methods of operation, resulting in the creation of wireframe prototypes. These prototypes underwent multiple user evaluations, which informed the iterative design process to refine the interface based on continuous feedback.For the hardware design of the control console, the task design was fundamental. The prototype included considerations such as installing a large touch display and was developed with the average physique of Japanese operators in mind, optimizing the placement and angles of the panoramic and operational screens. The prototype's shape was repeatedly refined to ensure optimal form while accommodating the operational needs.The final software prototype proposed a cockpit-type interface, consolidating the operational interface into a single touch-panel display. This display integrated functions such as radar, scheduling, camera feeds, and system controls, which were hierarchically organized to simplify operations. In particular, the scheduling display was designed to be compact, incorporating existing scheduling elements and spatially categorizing aircraft movements without overwhelming other displays. Design considerations also extended to readability, with user-friendly choices for font sizes and color schemes.The final hardware design prototype for the control console aimed for a form factor that ensured visibility and ease of operation for both the touch panel and panoramic screens. The design took into account operator comfort and included necessary features such as telephones and note spaces. The shape was organically designed to be familiar and comfortable for operators.In summary, this project successfully proposed designs for both software and hardware to enable the safe and efficient operation of the RDT system. While the designs prioritize safety, usability, and efficacy, it is acknowledged that the user evaluations conducted were limited. Future work will involve continuing to refine the designs based on broader user evaluations to achieve a higher level of design maturity.

Decisions about what airport configuration should be used and when the configuration should be changed are currently made manually by personnel in the Air Traffic Control (ATC) Tower (ATCT) or Terminal Radar Approach Control (TRACON). Over time, each airport has adapted unique local procedures related to airport configuration management, creating a challenge for both studying airport configuration management and developing decision support technologies. At many airports, the airport configuration decision is based primarily on the weather forecast and historical experience. While configuration changes to respond to weather changes are relatively straightforward, when traffic demand motivates a configuration change, the change is often made in reaction to observing aircraft queues and delays, or not made at all, rather than proactively based on forecast traffic situations. Consequently, significant opportunity exists for automation to support airport configuration decisions that will improve airport capacity and efficiency. Moreover, NextGen technologies and procedures will cause the definition of airport configuration to expand to include how metroplex resources other than the runways are utilized. As the metroplex configuration decision space becomes more complex, the need for supporting automation will become even greater. System Oriented Runway Management (SORM) is a concept in which the configuration and use of metroplex resources are explicitly planned with a holistic perspective of the operations within the metroplex as well as the needs of the metroplex within the context of the overall National Airspace System (NAS). System Oriented Runway Management is also a significant new research initiative by the NASA Airspace Systems Program that addresses the need for automation to achieve the SORM concept. This paper introduces the SORM concept and initial research to develop automation to support airport configuration planning.

This chapter describes the metrics for the validation of a Remote Tower Control workplace. The study shows how Air Traffic Control Officers (ATCOs) observe traffic from a Tower Control Working Position at Airport Erfurt-Weimar in comparison to a Remote Controller Working Position. Shadow-mode trials were used to cover perceptual, operational, and human factors aspects of a Remote Tower System, including a live video panorama and a research aircraft. The aircraft was used to fly different maneuvers within the aerodrome. These maneuvers allow insights on the detectability of an aircraft within different distances from the tower and the gathering of operation information about aircraft status. In addition, a vehicle was used to position static objects on the airfield to determine the detectability of these objects for different distances to the Control Tower (RTO-camera system). Eight ATCOs from the DFS participated in the validation exercise. Time-synchronized questionnaires for the controller working position remote (CWP remote) and the controller working position tower (CWP tower) were applied, addressing operationally relevant questions to the ATCOs. The validation exercise targets the evaluation of metrics that could help standardize the process of testing Remote Controller Working Positions. The results consider expense of realization, comparability, and feasibility as major classifications for the used metrics. Further, an approach for combining the classification into one score is presented to rank the metrics in relation to each other.