The cockpit was of the first workplaces to benefit from human factors research. Katherine Plant describes the evolution of the cockpit and the human factors implication of the new technology it contains.
One of the first formal human factors studies was carried out by Fitts and Jones in 1947 to analyse pilot experiences with display readings. Most of the early aviation human factors studies were concerned with control and display designs, demonstrating the design-induced traps that pilots could fall into. In the 1950s and 1960s human factors contributed towards crew selection, training and flight deck design. However, human factors in aviation came into its own in the 1970s and 1980s with the onset of crew resource management and the introduction of glass cockpits.
The flight deck has undergone a major transformation in recent years, going from the ‘classic flight deck’ with analogue dials and individual displays, to the ‘glass cockpit’, in which most instruments are presented via electrical screens and information is interlinked between the instruments, Flight Management System and autopilot functions. This evolution has been accompanied by the emergence of a whole host of human factors issues. Large research efforts have been devoted to understanding the associated cognitive factors such as situation awareness, workload and error, in addition to technological factors such as display design, Human-Machine Interface (HMI) and automation.
Most recently, the launches of Boeing’s 787 Dreamliner and the Airbus A350, have seen breakthrough technologies applied to all-new aeroplane design. It is not just the fixed-wing community that has seen significant technological advances. Rotary-wing manufacturers continue to develop state-of-the-art aircraft including AgustaWestland’s AW189 and Eurocopter’s EC175, primarily to service the demanding operating environments of oil and gas transport and Search and Rescue (SAR).
Today, the flight deck may look very different from the flight decks of WWII aircraft but human factors issues persist and evolve. Traditionally, safety and performance enhancements were the driving force for development. In recent years however, efficiency and competitiveness have become increasing incentives for development. This new aim is demonstrated by the changes in the way information is displayed to the pilot. For example, whilst the advent of Head-Up Displays and synthetic environments afford a safety benefit through increased awareness and reduced workload, they also allow for operations in degraded visual environments which increase efficiency and competitiveness.
ALICIA is a project that aims to develop new and scalable cockpit applications that can extend operations of aircraft in degraded conditions. It seeks to establish a common cockpit philosophy between different aircraft types and, ambitiously, between fixed and rotary-wing aircraft too. This article highlights some of the key technologies that are being considered within the project for future cockpits and discusses some of the associated human factors considerations.
Touchscreens allow the user to provide direct, context-sensitive interaction. In the cockpit, touchscreens have been considered for use as inter-seat controllers and armrest controllers and in instrument panels and multi-function display units. The use of touchscreens has commercial benefits in terms of commonality and scalability, particularly in relation to their ability to integrate increased functionality without any physical expansion.
Operationally, touchscreens also offer potential benefits in support of reduced crew operations, rapid aircraft start-up/take-off and information sharing between stakeholders.
It is envisaged that touchscreens will have an increased usability benefit over current units, which, due to the limited capacity of small screens, have narrow but deep menu control structures. The increased surface area afforded by entire touchscreen cockpits allows for broader and shallower menu control structures. Currently, many procedures depend on sequenced checks and actions on different panels distributed across the cockpit, particularly in relation to emergency procedures. The integration of these procedures into one area has the potential to reduce pilot workload and enhance situation awareness. Similarly, the use of touchscreens will promote better HMI consistency across the cockpit as common display philosophies can be utilised.
There are, however, potential issues and concerns that need researching. For example, arm fatigue and discomfort requires careful consideration. Touchscreens require direct interaction and therefore their positioning is limited by reach, which has consequences for the location of displays.
The need for feedback also requires careful consideration. The current use of physical buttons provides immediate feedback to the pilot. Haptic or audio feedback mechanisms are potential contenders to complement visual feedback. Furthermore, the effectiveness of touch-based interaction under conditions of turbulence or vibration is also of concern, as the motion of the screen and hand could lead to unintended interactions that have workload and safety implications. Ultimately, the resulting interface needs to be intuitive and unambiguous for the control and display of all aircraft functions, whilst providing the pilot with a comfortable interaction that can be used in all operating conditions.
Historically, there was no requirement for input devices in cockpits as displays were non-interactive. As functionality of the displays increased, so too did the need for suitable input mechanisms.
The introduction of novel input devices raises design issues as several bespoke interfaces become connected via one input device. Therefore, designers need to ensure they maintain the familiarity and functionality of existing systems whilst offering an effective redesign solution. Even with the introduction of touchscreens, a requirement remains for an indirect device as a back up method or to complement touchscreens in a multi-modal solution. Input devices that are being considered for use in future cockpits include:
Trackball: a ball held in a socket and rolled using the hand or fingers. They are advantageous in areas where there is limited surface space for device manipulation.
Rotary controller: this can be rotated, pushed down or moved up/down/left/right in order to control the movements and actions of an on-screen cursor. Rotary controllers have been shown to produce faster task performance than other indirect input devices.
Touchpad: this comprises a tactile surface which is capable of sensing the movement of a person’s fingers and translating this into actions of an on-screen cursor. Like trackballs, they require little space for installation and manipulation. However, trackballs can require more complex manipulations when compared with other input devices.
Direct Voice Input (DVI): this is likely to be the most flexible input application used in future cockpits. It has the potential to be used for a variety of tasks including radio tuning, navigation functions and checklist procedures. However, the usefulness of DVI is currently outweighed by a host of technical problems that need solving. These include adapting the vocabulary to be suitable for all accents, identifying individual speakers in multi-speaker environments and suppressing background noise.
Applications already exist that allow pre-recorded templates to be loaded to negate the problem of accents and the use of active input lines can resolve the issue of multi-speakers. DVI is a promising input technology but is only likely to be realised in future-future cockpits, not within the ‘2020’ vision that current research programs are aiming towards.
3D audio utilises natural audio processing capabilities through the positioning of audio signals in 3D space using appropriate hardware in order to emulate how audio is perceived in the natural world.
In the cockpit, this technology aims to improve situation awareness during fixed obstacle avoidance manoeuvring for rotorcraft. It has the potential to optimise crew workload in high communication density environments by spatially separating multiple simultaneous voice channels.
The HMI design for this technology needs to consider the comfort of the headsets and how best to track pilots’ head movements. This is because there is a small area in which this technology will work and it is dependent on the listener’s head position and orientation. The effectiveness of 3D audio is also dependent on the aural capability of the pilot, however this issue could be overcome via individual headsets, amplification aids and thorough and regular hearing tests.
There are slightly different considerations in a fixed-wing environment where pilots are not routinely required to wear headsets and rarely maintain head position for extended periods, except in critical phases of flight.
Advanced displays: Eyes out, head up and conformal symbology
The use of eyes out displays and appropriate symbology is considered to be a key enabler for enhancing operations in degraded visual environments and enhancing situation awareness. Due to operational differences between the two aircraft types, fixed-wing are likely to utilise Head Up Display (HUD) solutions, whereas rotary-wing are likely to use tracked Head Mounted Displays (HMD).
The eyes out displays will include both primary flight information and relevant conformal symbology such as landing sites. They will also allow the pilot to look through the displays to see the outside world. Displays are aligned at infinity so that the pilot can view real world objects and be presented with information on the display without having to adjust eye focus.
Current HUD technology does exist but offers a very limited field of view and so for longer flights the pilot must either maintain an uncomfortable position for extended periods or deviate from the design eye reference point, which has the potential for missed information. It is intended that these display interfaces will implement an augmented reality approach to allow for the presentation of 3D information onto the interface
In rotary-wing operations conformal symbology will be used to provide virtual 3D on route, approach and landing references, as well as primary flight and status data. The use of HUD symbology for fixed-wing aircraft is intended to provide significant capability enhancement to All Conditions Operations for taxiing, take-off and approach/landing. Expected benefits of the advanced displays include enhanced situation awareness and increased safety with regards to airborne obstacles and navigation hazards. Human factors evaluation trials are underway to assess the various implications of using advanced displays including situation awareness, workload and general usability of the displays.
Future challenges for human factors
With any introduction of new technology, as old problems are addressed, new issues may arise. The human factors discipline has an important role to play in the evaluation of new technologies to ensure that both physical performance and cognitive processing is optimised to enable successful task performance. The physical arrangement of new technologies is as important as the cognitive demand they impose, as both play an integral part in the success of the human-machine interaction.
The aviation domain has often led the way in its acknowledgement and acceptance of the importance of human factors considerations. The requirement for rigorous human factors analyses of human-technology interaction becomes especially pertinent when new technologies are introduced into an already complex environment.
The human factors specialists within the ALICIA project are currently facing the challenge of defining the scope of evaluation trials. It is relatively simple to evaluate an isolated piece of technology but this process gets increasingly complex as more technologies are introduced into a future cockpit test bed. Questions arise as to how these technologies can be simultaneously evaluated to assess the merits of an overall future cockpit, whilst capturing the salient strengths and weaknesses of individual technologies.
The methods used to do carry out this complex evaluation also require careful consideration. Eye tracking, video capture, simulator data logging and qualitative self-assessments are all likely to play a part in evaluating the future cockpit concept. When coupled with the constraints of cost and time-effective trials, the need to demonstrate value is ever present.
These technologies provide just a taster of the cockpit of the future. The ideal cockpit will be capable of supporting the ever-changing Air Traffic Management environment and operating within the demands of All Conditions Operations whilst providing a scalable solution that is physically and cognitively optimised for the pilot.
By Katherine Plant, Research Assistant in the Transportation Research Group, Catherine Harvey, Research Fellow & Neville Stanton, Chair of Human Factors, all in the Transportation Research Group, Faculty of Engineering and Environment, University of Southampton.
This article was first published in issue 520 of The Ergonomist, October 2013.