Controller-pilot Communication Research Articles

UAV Detect and Avoid from UTM-Dependent Surveillance

A hierarchical unmanned aircraft system (UAS) traffic management (UTM) system has deployed 45 ground transceiver stations (GTS) for UAS services in Taiwan. This UTM system covers most areas for UAV-dependent surveillance using ADS-B Like technology. UTM Controller can monitor all UAV flights under transparent surveillance in low airspace. Controller-initiated UAV “detect and avoid” (DAA) mechanism assists UAV separation to ensure flight safety on UTM for small multirotor UAVs. From similar concept to traffic alert and collision avoidance system (TCAS) for the manned aircraft system, the UTM software executes DAA functions to generate approach alerts to UTM Controller. Conflict is detected by heading arrow extrapolation from multiple approaching UAVs by their time to conflict (TTC) on icons. Traffic advisory (TA) and resolution advisory (RA) are pronounced on UTM console to controllers. The less priority UAV pilot will receive the controller-pilot communication (CPC) to perform avoidance resolution. In UTM, the surveillance data period is broadcasting at 5~8 seconds on LoRa (long-range wide-area network) chip. Referring to TA=48 seconds and RA=24 seconds, the signal delay in ADS-B Like system to UTM server is about 0.5 seconds and CPC response is measured about 3~5 seconds. From real flight tests, the RA is enough for the less priority pilot to maneuver UAV for avoidance. From real flight tests, the proposed DAA mechanism based on UTM-dependent surveillance is feasible to resolve multiple approaches. The developing UTM system using ADS-B Like technology is also examined of high availability with redundant reliability and performance stability for flight safety.

Subjective measures of communication errors between pilots and air traffic controllers

Communication errors between aircraft pilots and air traffic controllers are one of the most critical issues for aviation safety. Air traffic controller and pilot interaction may involve communication errors, becoming the most common factor combination that leads to a number of high-severity aviation incidents. This study explored the factors and aviation occurrences of pilot-controller communication errors and offered several recommendations to improve flight safety. The perspectives of pilots and air traffic controllers were separately analyzed via two differently designed survey questionnaires. Then, t-tests, analysis of variance, factor analysis, and linear regression analysis were performed to analyze the survey results, and concluded five factors, two communication errors, and two main aviation occurrences. Based on the results, this study suggested improving controllers' professional abilities, such as using the correct phraseology, listening comprehension, concentration, and giving accurate, clear and concise instructions. Strengthening pilots' training on situational awareness, standard operating processes, and urgent problem-solving is also critical. Crew resource management should be highlighted to improve communication between pilots and controllers. The findings of this study serve as reference to reduce communication errors and improve aviation safety.

A Comparative Study of Speaker Role Identification in Air Traffic Communication Using Deep Learning Approaches

Automatic spoken instruction understanding (SIU) of the controller-pilot conversations in the air traffic control (ATC) requires not only recognizing the words and semantics of the speech but also determining the role of the speaker. However, few of the published works on the automatic understanding systems in air traffic communication focus on speaker role identification (SRI). In this article, we formulate the SRI task of controller-pilot communication as a binary classification problem. Furthermore, the text-based, speech-based, and speech-and-text-based multi-modal methods are proposed to achieve a comprehensive comparison of the SRI task. To ablate the impacts of the comparative approaches, various advanced neural network architectures are applied to optimize the implementation of text-based and speech-based methods. Most importantly, a multi-modal speaker role identification network (MMSRINet) is designed to achieve the SRI task by considering both the speech and textual modality features. To aggregate modality features, the modal fusion module is proposed to fuse and squeeze acoustic and textual representations by modal attention mechanism and self-attention pooling layer, respectively. Finally, the comparative approaches are validated on the ATCSpeech corpus collected from a real-world ATC environment. The experimental results demonstrate that all the comparative approaches worked for the SRI task, and the proposed MMSRINet shows competitive performance and robustness compared with the other methods on both seen and unseen data, achieving 98.56% and 98.08% accuracy, respectively.

CLARITY AND PRONUNCIATION OF AB-INITIO AIR TRAFFIC CONTROLLER

The increasing number of aircraft flying around the world has led to the requirement for air traffic controllers to improve their communication skills to face high demand traffic in the future. The paper examines the communication errors in the pilot-controller communication of six ab-initio air traffic controllers during simulation training. More than three hours of conversation were collected and analyzed qualitatively using conversational analysis. The transcribed data yielded a total of 62 instances of communication errors. The data revealed that clarity and pronunciation of ab-initio controllers contributed to problematic communication and reduced the efficiency of the air traffic controllers in communicating. In contrast, pronunciation errors rarely diminished comprehension amongst the controllers and pilots who share a similar first language and are familiar with the use of English in a lingua franca setting. The study also describes other instances of communication errors in pilot-controller communication. The results indicate that ab-initio air traffic controllers need to be proficient in three main areas in pilot controller communication to improve their performance: aviation phraseology, aviation English, and aviation knowledge. The findings suggest that pilots and air traffic controllers should achieve level 4 (operational) in aviation language proficiency test, before proceeding to aviation training that requires them to be proficient in their language skills.

Development of Hierarchical UAS Traffic Management (UTM) in Taiwan

The unmanned aerial vehicles (UAVs) will soon be legally flying into airspace in Taiwan and many countries. UAS traffic management (UTM) becomes an important issue to challenge aviation safety. A hierarchical UTM is proposed and constructed based on the concept of Air Traffic Management (ATM) for the manned aviation system. The proposed Regional UTM (RUTM) and National UTM (NUTM) are hierarchical infrastructure to offers traffic management services for all legal UAV flights in Taipei Flight Information Region (TPE FIR) under and over 400 feet. The proposed UTM provides UAV/pilot log-in/out, flight planning, geo-fencing, detect and avoid (DAA), logbook records, big data analysis, ground control redundant support and controller-pilot communication on multi-window monitor system. UTM data are encrypted to prevent hijacking threat to low altitude UAVs. The UTM adopts ADS-B Like communication infrastructure to offer affordable cost for all UAVs with high reliable surveillance data reporting. The ADS-B Like surveillance mechanism includes 4G/LTE, LoRa, APRS and XBee. Their gateway deployment is designed and constructed with supports of Chung Hua Telecommunication (CHT) in urban and suburban areas. While those remote areas, such as mountain and deep forest, the National Forest Bureau workstation will be selected. The ADS-B Like communication will cover full airspace in Taiwan. Surveillance data reliability, continuity, integrity and availability will be examined by flight tests. The proposed Hierarchical UTM will launch trial runs in Tainan County of RUTM operation to verify the proposed concept, system performance and general operation into the national “UAS Innovative Experiment Project”.

Understanding Controller-Pilot Interaction Dynamics in The Context of Air Traffic Control

LiteratureNew capabilities to modernize the U.S. National Airspace System (NAS) include support of real-time information streams derived from many data sources across the NAS. As an emergent proper...

Miscommunication in Pilot-controller Interaction

English is the preferred language for communication in the aviation industry. Pilots and air traffic controllers of different nationalities and proficiency levels interact with each other using a specialized form of English termed aviation English that comprises of aviation phraseology and “plain English”. Here, miscommunication could have disastrous consequences. This paper presents the findings of a study that explored instances of miscommunication in the interaction between pilots and controllers. Miscommunication is defined as a lack of understanding (or misunderstanding), non-understanding or misinterpretation of messages in communication. The corpus consists of 30 hours of actual pilot-controller audio communication collected from the Malaysian airspace. Data were collected from three different frequencies (Alpha, Bravo and Charlie) representing different phases of the flight. They were analysed qualitatively using conversation analysis techniques. The study found that miscommunication in pilot-controller communication is due mainly to two main factors, procedural deviation and problematic instruction or request. The paper concludes by suggesting that pilots and controllers should adhere to standard phraseology and avoid code-switching from aviation phraseology to plain English except when it is inadequate for the situation. It also suggests that proper radio discipline should be maintained. Keywords: aviation English; miscommunication; non-native speakers; pilot-controller communication; ESP

Task-Oriented and Relationship-Building Communications between Air Traffic Controllers and Pilots

By questioning the lopsided attention on task-oriented factors in air traffic controller-pilot communication, the current study places an equal weighting on both task-oriented and relationship-building communications, and investigates how each type of communication influences sustainable performance in airline operation team. Results show that both task-oriented and relationship-building communications in terms of sustainability of team process predicted greater communication satisfaction at work. Also, both task interdependence and shared leadership influenced both types of air traffic controller-pilot communication. However, only relationship-building communication had a direct influence on perceived work performance whereas task-oriented communication had not. Along with task-oriented factors, this study raises the relationship-oriented factors as important resources for the sustainable team performance in airline industry.

MODELLING THE ORAL COMMUNICATION PERFORMANCE OF AIR TRAFFIC CONTROL

This study proposes a mechanism for measuring pilot-controller communication errors and develops a model to evaluate their communication performance. Empirical data based on 73 transcripts of communication from the Taipei Flight Information Region (FIR) are analyzed to validate the developed model and investigate communication issues. The results show that about 87% of all communication errors found in the transcripts had a relatively low level of influence on flight safety, while 13% had a severe influence. Additionally, the results of performance measurement indicate that the overall level of communication performance is relatively low. These findings are expected to be applicable to other countries whose native languages are not English. The performance model developed in this study can help management in the industry to evaluate radio communication performance of their aviation personnel.

FAA Air Traffic Control Front Line Manager’s Quick Reference Guide

Air Traffic Control Front Line Managers (FLMs) influence the prevention of operational incidents (OIs) and runway incursions (RIs) through practices that enable safe controller performance and mitigate problems related to specific contributing factors, including controller coordination, controller-pilot communication, and controller memory. FLMs’ proximity and frequent interactions with controllers in the operational environment place them in a unique position to impact air traffic safety through managing controller performance and mitigating OIs and RIs resulting from common contributing factors. With this understanding of the FLM role, The Federal Aviation Administration (FAA) developed the Front Line Managers Quick Reference Guide (QRG). The Civil Aerospace Medical Institute (CAMI) assisted the Air Traffic Organization (ATO) with the organization and evaluation of these materials. The guide was intended to provide a management best practices format specific to Air Traffic Control to assist FLMs in the performance of their job. To determine the utility of the QRG, CAMI developed and administered a survey of FLMs. The survey also provided the ATO with a basis for additions or deletions to the QRG. The FLM QRG was designed as a best practices guide for use by all field FLMs. Survey results and suggestions and recommendations from survey respondents are presented.

Understanding the Human Component of Area Navigation Procedures Across the National Airspace System

The FAA intends to considerably increase the usage of area navigation (RNAV) approach and departure procedures in order to achieve the proposed NextGen goals for improved efficiency and capacity. RNAV procedures enable aircraft to have better access and flexibility for point-to-point operations. In an effort to better understand the potential impact of increased RNAV usage, a human factors safety assessment was conducted to identify the key human factors issues present in current RNAV operations. An analysis of 100 RNAV narrative-based safety reports from the Air Traffic Safety Action Program (ATSAP) and 68 narrative-based safety reports from the Aviation Safety Reporting System (ASRS) was conducted to identify key causal factors. The analysis found several key causal factors related to RNAV procedure design, controller-pilot communication, automation systems, and track deviations. Specific human performance concerns and mitigation strategies for each causal factor were developed. These results should drive future requirements associated with the implementation of future RNAV procedures.

NextGen Flight Deck Data Comm: Auxiliary Synthetic Speech – Phase I

Data Comm—a digital, text-based controller-pilot communication system—is critical to many NextGen improvements. With Data Comm, communication becomes a visual task. Although Data Comm brings many advantages, interacting with a visual display may yield an increase in head-down time, particularly for single-pilot operations. This study examined the feasibility of supplementing the visual Data Comm display with an auxiliary synthetic speech presentation. Thirty-two pilots flew two experimental scenarios in a Cessna 172 Flight Training Device. In one scenario, ATC communication was with a text-only Data Comm display; in the other, the text Data Comm display was supplemented with a synthetic speech display annunciating each message (i.e., text+speech). In both scenarios, pilots heard traffic with similar call signs on the party line and received a conditional clearance; however in just one scenario (counter-balanced between communication conditions), pilots received a clearance that was countermanded by a live controller before it was displayed. Results indicated that relative to the text-only display, the text+speech display aided single-pilot performance by reducing head-down time; and it may have prevented participants from acting prematurely on the conditional clearance. Supplementing text Data Comm with speech did not introduce additional complications: participants were neither more likely to erroneously respond to similar call signs, nor to ignore a live ATC voice countermand. The results suggest that the text+speech display did not hinder single-pilot performance and offered some benefits compared to the text-only display.

Effects of controller-pilot communication medium, flight phase and the role in the cockpit on pilots’ workload and situation awareness

This study explores the effects of communication medium, flight phase, and the role in the cockpit on pilots’ workload and situation awareness. Eight pilots with the experience of Controller-Pilot Data Link Communications (CPDLCs) participated in this simulated experiment. Two types of communication medium (voice and datalink), three types of flight phase (departure, cruise, and arrival), and two types of role (pilot flying and pilot non-flying) were investigated in the experiment. The results indicated that flight phase is a significant factor and cruise is the most suitable phase for datalink use on pilots’ acceptance, workload, and situation awareness performance. Both medium and role were not the significant factors. Since there is no significant difference on medium when no extra tasks and interferences involved in a normal flight, that the use of CPDLC can be justified during all phases of a no-event flight. In addition, the results of usability indicated that the simulated CPDLC with command selection functions proposed in this study provides good utility for the participants. In order to use the CPDLC for all phases of flight in the future, adding more command selection functions in place of typing messages by pilots and accommodating appropriate interfaces for different phases are recommended to enhance the usability of the CPDLC unit.

Evaluation of Airspace Complexity and Dynamic Density Metrics Derived from Operational Data

Mental workload experienced by air traffic controllers cannot be measured directly but may be inferred from observable performance or task load imposed on them by volume and complexity of traffic. This research evaluated several measures used to quantify the aforementioned variables. Data were obtained from Indianapolis (ZID) and Kansas City (ZKC) centers and processed by a modified objective activity and task load assessment program, POWER. We compared sectors with different characteristics to measures of pilot-controller communications and to sector complexity metrics, derived from the POWER output. Results from ZKC data were evaluated against subjective workload ratings. The ZID results were consistent with the different characteristics of the selected sectors. Dynamic density correlated with subjective workload estimates and controller transmission durations, known to be a workload indicator. This research demonstrated the viability of extracting metrics relevant to controller task load from operational data and the practicability of implementing additional algorithms to the POWER program for derivation of new metrics.

Time Delays in Air Traffic Control Communication Loop: Effect on Controller Performance and Workload

The impact of digital technology-induced delays in the pilot-controller communications on air traffic controllers' performance and workload was investigated in 2 experiments manipulating systemic audio delay (AD) and variable pilot delay (PD). Vectoring accuracy (Experiment 1), lateral separation between 2 aircraft on converging tracks (Experiment 2), and subjective workload (NASA-Task Load Index) were measured. In Experiment 1, the effect of AD was measurable but not statistically significant; PD reduced accuracy and resulted in earlier turn initiations. In Experiment 2, both AD and PD significantly reduced separation between aircrafts. Short communication delays, however, did not substantially degrade controller performance in the experiments.

The Impact of Communication Delays on Air Traffic Controllers' Vectoring Performance

An experiment was conducted to investigate the impact of communication delays in the pilot—controller communication loop on air traffic controllers' performance and workload. Four levels of constant systemic audio delay (AD), 150, 250 ms, 350 ms, and 1,000 ms, and two levels of variable pilot delay (PD), zero delay and realistic delay, were employed. Vectoring accuracy and the controller's final turn initiation served as dependent variables. Subjective workload was measured by the NASA-TLX workload index. Eight subjects proficient in the task participated in the experiment. Random PD had significant effects on both vectoring accuracy and final turn initiation; accuracy was reduced and initiation times were earlier when PD was added. However, data showed no effect of AD on vectoring accuracy, and no evidence of compensatory strategies in response to increasing AD levels. Results suggest that variability in the subjects' turn initiation effectively masked the impact of even the longest AD of 1,000 ms on vectoring accuracy. The NASA-TLX showed no effect of AD on workload in either PD condition.

Pilot Error in Copying Air Traffic Control Clearances

A study investigating the accuracy of pilots' copying air traffic control clearances is described. Twentyfour airline pilots listened to 28 taped clearances and copied them down on an answer sheet using shorthand, longhand, or some combination of these according to their preferences. The copied clearances were analyzed by the number of correctly copied elements, the number of omitted elements, and the number of extraneous elements that were not present in the original clearance. Preliminary results indicate a strong influence of habit and familiar operating environment and procedures on the accuracy of copying unfamiliar information. Common errors included victor-airways copied as jet-airways, low altitudes copied as much higher, and slow speeds copied as much higher. The vulnerability of controller-pilot communications to the effects of unfamiliarity is apparent. A detailed analysis of these data may provide for a better understanding of the shortcomings of controller-pilot communication.

Analysis of Problems in Routine Controller-Pilot Communication

Previous studies of controller-pilot communication have identified communication problems but not how often or why they occur. A more complete picture of these problems requires an understanding of how controllers and pilots successfully communicate during routine operations. We describe a field study of routine controller–pilot communication and the problems that disrupt this communication. Guided by a model of collaboration during communication, voice tapes of communication during terminal operations were coded and analyzed. Two kinds of communication problems were examined: (a) procedural deviations (e.g., partial readbacks) and (b) inaccuracies (e.g., incorrect readbacks). The results suggest that these problems are infrequent events in routine communication. However, they are associated with communication factors such as air traffic control message length and composition and traffic level. These relations suggest potential causes of problems that disrupt routine controller–pilot communication.

Controlled Flight into Terrain Accidents: System-Induced Errors

Controlled flight into terrain accidents are those in which an aircraft, under the control of the crew, is flown into terrain (or water) with no prior awareness on the part of the crew of the impending disaster. This paper examines recent experience with these accidents, seeing them as the result of errors generated by a complex air traffic control system with ample opportunities for system-induced errors. Such problem areas as pilot-controller communication, flightdeck workload, noise-abatement procedures, government regulation, visual illusions, and cockpit-and ground-radar warning devices are discussed, with numerous examples of recent accident cases. The failure of the human factors profession to play a more significant role in the air traffic complex is also considered.