Christoph Moehlenbrink

Colored Petri Net based formal airport control model for simulation and analysis of airport control processes

The development of the experimental Remote Tower Operation Human Machine Interface and the new Remote-Controller work position is supported by a cognitive work and task analysis (CWA) of the presently existing work environment and decision processes at airport Leipzig. This paper presents a formal approach for the description of the whole Human Machine System. It is shown how the results of a cognitive work analysis on a medium size airport are transferred into a formal executable human machine model for simulating the controllers work processes in relation to the airport processes. The model is implemented with Colored Petri Nets. The mathematical basis of Petri Nets allows a formal analysis of whole systems. Critical system states and inconsistencies in the human machine system are identified through comparison of knowledge states of the controllers with process states of the airport system by using State Space analysis. The represented formal work process model provides a valuable support for the communication between domain experts and system developers.

Monitoring principles in aviation and the importance of operator redundancy

The aim of this paper is to discuss developments in aviation with respect to their affect on redundancy and dependability of the complex human-automation system. With the improvement of technical systems and increasing automation in aviation, the attempts to reduce the number of human operators in the flight guidance system is still one goal of current research. Single pilot cockpit or single controller working positions are the key words for pinpointing this issue. For technical systems, the developments aim at the integration of a higher level of redundancy to improve the dependability. A contrary trend is determinable for the human operator by transitioning to single operator systems. To be able to evaluate this process, this paper analyses three different monitoring principles that form the basis for redundancy and thus dependability. These monitoring principles are (a) the automation-automation, (b) the human-automation, and (c) the human-human. Research that focuses on single operator systems consequently eliminates the human-human monitoring principle. The authors argue that the consequences of this elimination are currently not understood sufficiently and may have a great impact on the dependability of the overall system, as some highly valuable aspects of the human-human monitoring principle would be irreplaceably lost with the transition to single operator systems.

Does Cognitive Lockup Depend on the Situation, on the Person, or on an Interaction of Both?

This paper focuses on investigating (a) whether cognitive lockup can be provoked in an experimental setup in a realistic, generic cockpit simulator and (b) whether the occurrence of cognitive lockup further depends on the pilot or on an interaction between the aviation situation and the pilot. To investigate these research questions, an experiment was conducted during which pilots aviated two scenarios. Both scenarios reflect an approach situation in which the second autopilot failed as a first event and the runway was changed as a second event. The main difference of the scenarios is the timing of the autopilot failure and the runway change: In the experimental condition, the events occurred later in time, which reduced the time frame available for the briefing. While aviating, the aircraft’s maximum deviation from the specified route was recorded. Statistical analyses showed that pilots were more drawn to cognitive lockup in the situation with more time-pressure resulting in a performance degradation in the aviation task. Aviation performance was further predicted by a significant interaction between the person and the situation, which shows a need to also consider person-related variables when explaining the occurrence of cognitive lockup.

Operationalization of Learned Carelessness An Experimental Approach

The theory of learned carelessness offers an explanation why humans take unnecessary risks by omitting safety precautions against better judgment, but empirical research on learned carelessness is scarce. To test the theory 16 commercial aircraft pilots inspected flight plans on a multi-function display and the occurrence of flight plan errors was manipulated. Pilots rated effort of check performance, risk resulting from check omission and we measured the rate of falsely accepted erroneous flight plans. Participants who repeatedly encountered erroneous flight plans detected more errors during the test phase than participants who previously received only error-free flight plans (p < .01). The results provide evidence that subjective risk resulting from check omission affected the development of learned carelessness (p = .053), while effort of check performance displayed no effect (p = .80) due to invariance in ratings.

Investigating attentional tunneling through a flexible experimentation environment and eye tracking

Although attentional tunneling as a phenomenon is at least known since the late 1970ies, it is still an area of high research interest, since it bears connections to current and future applications in head-up and head-down displays. For example, it is still not fully answered to what degree highly dynamic scenarios influence the pilots ability to keep up with routine tasks, and vice versa, when and whether dynamic scene changes stay unnoticed under high workload. In order to further investigate attentional tunneling a generic experimentation environment was set up. The core of the environment is DLRs flexible sensor simulation suite (F3S). This simulation software can be installed on specialized simulation platforms, for example a Vision Station, as well as on standard workstations and can be tuned to a simple view simulation with different levels of realism. It allows for a full and dynamic control of experimental scenarios, for example possible changes in the environment. For larger scenarios several platforms can be coupled to enable the investigation of team situations. As one of its key features the set-up includes a full eye-tracking solution that is further capable of recording dynamic areas of interest. Within a first experiment with a student sample F3S was used as a simple view simulation combined with synthetic approach scenarios. Subjects were asked to detect changes whilst flying highway-in-the-sky approaches with a head-up display. At the same time eye gaze positions where tracked. This novel approach to the investigation of attentional tunneling can prove that an environmental change, even though visually perceived, is not necessarily cognitively processed at the same time.