RTCA DO-372

Description / Abstract: PURPOSE AND SCOPE

Introduction

The objective of this document is to increase human factors¹ awareness by the individuals who are responsible for the design and certification of systems and equipment and related interfaces designed for use by the flightcrew. This applies to systems and equipment that are certified at the box level or installation level. The term “flightcrew” is used in this document to represent a pilot, flight engineer, or flight navigator assigned to duty in an aircraft during flight time per Title 14 Code of Federal Regulations (CFR) Part 1 Section 1.1. This document aims to facilitate the identification of flightcrew interface aspects, considerations, and risks to design and aid the resolution of the human factors issues associated with the avionics. The importance of addressing the human factors aspects of the design is highlighted in the Operational Use of Flight Path Management Systems - Final Report of the Performance-based Operations Aviation Rulemaking Committee/Commercial Aviation Safety Team, Flight Deck Automation Working Group that identifies incidents and aviation accidents that have occurred due to pilot-machine interface breakdowns, such as manual flight path control errors, controlled flight into terrain, mode confusion, and over reliance on automation. The report highlights the impact of highly integrated flight decks² and poorly integrated retrofit solutions and how each can increase the flightcrew knowledge requirements and add complexity, which may result in pilot confusion and errors during flight operations in all phases of flight.

The Federal Aviation Administration (FAA) previously documented information on human factors in the expired FAA Notice 8110.98, Addressing Human Factors/Pilot Interface Issues of Complex, Integrated Avionics as Part of the Technical Standard Order (TSO) Process. This RTCA document extends the expired Notice beyond avionics submitted for new or amended Technical Standard Order (TSO) Authorization to include installed electronic systems (and associated controls, displays, labels, and placards) used by the flightcrew³ that are submitted for a Type Certificate (TC), Supplemental Type Certificate (STC), or Amended Type Certificate (ATC) under 14 CFR and Certification Specification (CS) Parts 23, 25, 27, and 29. The FAA intends to implement this document in an information-only advisory circular (AC). Regulatory and guidance material takes precedence over this document.

This document outlines a process for identifying the flightcrew interface aspects of a system as part of the engineering design and certification process, and provides previously approved design examples of how human factors aspects were addressed. Neither the process nor the examples are meant to be prescriptive. Therefore, “must” statements are not contained herein unless they refer to certification authority regulations. Good practices and lessons learned are provided as a means to inform the development and certification process in an effort to avoid common pitfalls that have been observed in past certification efforts.

It is assumed that the reader has an understanding of human factors or access to human factors specialists and therefore this is not a ‘how to’ human factors document. The intended readers include Original Equipment Manufacturers (OEMs), including the Designated Engineering Representatives (DERs), Authorized Representatives (ARs), Unit Members (UMs) or Organization Designation Authorization (ODA) holders who represent both industry and the certification authority, flight test pilots, flight test engineers, as well as human factors specialists and other personnel at the Aircraft Certification Offices (ACO) and Flight Test Branch of the appropriate certification authority. This document is meant to aid in the early identification of human factors aspects and the resolution of flightcrew interface issues as part of the engineering design and certification process, but is not intended as an MOC for certification.

This RTCA document contains the following sections:

Section 1 covers the introduction and overview of the document (current section).

Section 2 presents recommended steps for evaluating the human factors/pilot interface aspects of flightcrew systems during the engineering design and certification process to facilitate future approvals and streamline or establish commonality in the certification process. The process is not intended as a means of compliance (MOC) but rather as guidance for identifying and resolving flightcrew interface issues. Section 2 describes an iterative approach in which human factors aspects are identified, addressed and issues resolved continuously throughout the development program and not something left for the formal test phase at the end of a certification program. The recommended process has been successfully applied in previous aircraft programs and can be used as a guide for both the applicant and the certification authority as they go through a certification program. The process described in Section 2 is intentionally generic so as to fit into the overall certification effort, with the understanding that the scope of the activities should be tailored to the size of the project. Adherence to the process is a recommendation only. To assist in the evaluation of human factors aspects, good practices from past certification programs are provided as examples for carrying out each process step.

Section 3 provides examples of prevalent, recurring human factors/pilot interface issues that have been identified during previous certification programs. The identified issues are not a comprehensive list of all possible flightcrew interface issues but are meant to serve as an aid in the early identification of certification topics of discussion. Approved design examples emphasize the design aspects that resolved a particular human factors issue but are not the only method available to address the issue. Implementing the design examples in this document does not guarantee certification approval but instead represent good design practices that have led to an effective means for resolving the issue. Also included are a number of lessons learned that include design and evaluation considerations from a human factors perspective. When existing regulations and guidance are applicable, it is noted. The human factors topics compiled from previous programs that generated the most frequently recurring certification issues include:

• Display Hardware Characteristics (Display Viewing Envelope, Display Luminance, Reflectivity, and Brightness Control including Retrofit Considerations, Latency)

• Information Presentation (Color including Retrofit Considerations, Symbology, Display Labeling, Clutter, Timeliness of Information)

• Alerting, Annunciations, and System Status Indications (Degradation of Sensor Sources, Crew Alerting Systems, Inhibits and Control of Nuisance Alerting, Retrofit Considerations: Integration Using Equipment from Multiple Suppliers)

• Controls (Feedback, Control Labeling, Functionality, Cursor Control Devices, Touch Screens)

• Flight Deck Arrangement (Visibility and Readability, Reach Accessibility)

• Automatic Flight Control and Flight Guidance Systems (Awareness of System Modes and States, Low Speed Alerting and Mode Transitions, Autopilot Engagement/Disengagement, Manual Control During Autopilot Use, Vertical Navigation, Retrofit Considerations: Flight Directors and Flight Path Markers, Retrofit Considerations: Automatic Flight Control System (AFCS) and Autopilot (AP) Integration with Servos)

Section 4 provides the list of committee members.

The document also contains four appendices.

Appendix A contains human factors related regulatory references and guidance applicable to Title 14 CFR for Parts 23, 25, 27 and 29 aircraft, and European Aviation Safety Agency (EASA) CS for Part 25. Also, industry standards and other human factors related documents referenced in this document are listed in this appendix.

Appendix B provides websites for human factors related regulatory and guidance material and industry documents.

Appendix C contains the glossary of terms used in this document.

Appendix D is a list of acronyms and abbreviations. Note that throughout the document regulations and guidance material are referenced. When the guidance is applicable to all Title 14 of the Code of Federal Regulations, Parts 23, 25, 27, and 29 aircraft, the abbreviation 2X is used, such as 2X.1301 Function and installation.

In this document, technical and guidance references with “()” indicate that the most recent version of the reference should be used. See Appendix A for the versions available at the time of publication of this document.

¹The FAA Reauthorization Act of 2016 defines human factors as “a multidisciplinary field that generates and compiles information about human capabilities and limitations and applies it to design, development, and evaluation of equipment, systems, facilities, procedures, jobs, environments, staffing, organizations, and personnel management for safe, efficient, and effective human performance, including people’s use of technology”. When applied specifically to the field of aviation, the aim is to use human factors knowledge to improve safety, efficiency, performance, and reliability through the focus on how pilot performance is impacted by systems, procedures, and training.

²The term “flight deck” is used interchangeably with “cockpit” throughout the document. There is no difference in meaning between the two terms as used in this document.

³ For the purposes of this document, the term “avionics” includes installed electronic systems and all associated controls, displays, labels, and placards used by the flightcrew.