A Handbook for Effective Signaling in Air Traffic Control

The Federal Aviation Administration’s air traffic control organization (ATO) encompasses a variety of facilities that include towers, terminal radar approach control facilities (TRACONs), and air route traffic control centers (ARTCCs). Air traffic controllers continually evaluate the impact of such factors as weather, converging traffic, and emergency situations, using this information to prioritize tasks and solve problems before they can impact flight safety. Controllers generally rely on prospective memory, trying to anticipate events and working proactively to avoid loss of separation or other situations in which an alarm or alert would be required. The purpose of an alarm is to get the immediate attention of a human operator when an abnormal event occurs. Alarms are therefore designed to be intrusive and distracting. Frequent interruptions from nonactionable alarms can disrupt the controller’s prospective memory, and there is evidence that improving the design of alarms and alerts can prevent errors (Loft, 2013). There are additional important reasons to improve the sensitivity and specificity of alarms and to harmonize alarms across equipment and the ATO. Alarm systems that are perceived to be unreliable are likely to provoke the so-called cry-wolf effect (Breznitz, 1984), especially during periods of high workload (Bliss, 2000). A critical first step for solving the problems described above is to create a handbook to guide signaling practice across all ATC facilities. The project team will leverage results of past scientific research regarding signal effectiveness to build an informative resource for controllers and signal designers. After completion of the handbook, the project team will plan to develop a training program for air traffic controllers that provides guidance on how to make the best use of signaling functions to ensure safety. This program will help air traffic controllers to anticipate signals and rely on them appropriately during critical periods, while minimizing the risk of alarm fatigue. Ultimately, well trained controllers should exploit alarms, alerts and warnings to build situation awareness and to lessen cognitive workload.

  • Record URL:
  • Supplemental Notes:
    • ATO Research Requirements Roundtable item AJM-FY19-5. The FAA does not have a Human Factors handbook or guide to assist in the development of system design or associated training requirements for integration of alarms and alerts into air traffic systems. While the FAA has a few standards associated with AT system alarms and alerts, there is no relevant, guiding documentation for how to develop or integrate alarms and alerts or how to properly train system users of alarms and alerts. The FAA should determine a standardized methodology to determine how and when to use various kinds of alarms and alerts during system design and development in order to help reduce the number of each and their potential for repetitiveness, redundancy, conflict or confusion, and nuisance caused by any of these conditions. Similarly, end-user training standards should be developed to help reduce confusion, misunderstanding, misinterpretation, of alarms and alerts due to absent or inadequate understanding of each.


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  • Status: Active
  • Funding: $681000
  • Contract Numbers:

    Cooperative Agreement 692M151940006

  • Sponsor Organizations:

    Federal Aviation Administration

    800 Independence Avenue, SW
    Washington, DC  United States  20591
  • Managing Organizations:

    Federal Aviation Administration Office of NextGen Human Factors Division (ANG-C1)

    800 Independence Avenue SW
    Washington, DC  United States  20591
  • Project Managers:

    Kaufmann, Karl

  • Performing Organizations:

    University of Chicago

    5801 South Ellis Avenue
    Chicago, IL  United States  60637-5418
  • Principal Investigators:

    Ruskin, Keith

  • Start Date: 20190927
  • Expected Completion Date: 20240926
  • Actual Completion Date: 0
  • USDOT Program: Air Traffic Control/Technical Operations Human Factors
  • Subprogram: Human Factors Design Standards, Guidance, and Studies Supporting NAS Technology Integration
  • Source Data: PHASE YEAR FUNDING Phase I 2019 $139,707.00 Phase 2 2020 $137,027.00 Phase 3 2021 $132,904.00 Phases 4 and 5 2022-2023 $272,162.00

Subject/Index Terms

Filing Info

  • Accession Number: 01724687
  • Record Type: Research project
  • Source Agency: Federal Aviation Administration
  • Contract Numbers: Cooperative Agreement 692M151940006
  • Files: RIP, USDOT
  • Created Date: Dec 6 2019 8:55AM