Runway incursions

Abstract. This paper introduces an agent-hased approach to analyze the dynamics of accidents and incidents in aviation. The approach makes use of a number of elements, including formahzation of a real world scenario, agent-based simulation of variations of the scenario, and formal verification of dynamic properties against the (empirical and simulated) scenarios. The scenario formalization part enables incident reconstruction and formal analysis of it. The simulation part enables the analyst to explore various hypothetical scenarios under different circumstances, with an emphasis on error related to human factors. The formal verification part enables the analyst to identify scenarios involving potential hazards, and to relate those hazards (via so-called interlevel relations) to inadequate behavior on the level of individual agents. The approach is illustrated by means of a case study on a runway incursion incident, and a number of advantages with respect to the current state-of-the-art are discussed. 

As an alternative, the current paper presents an approach for analysis of aviation incidents that takes a multi-agent perspective, and is based on formal methods. The approach is an extension of the approach introduced in the work of Bosse and Mogles [4], which was in turn inspired by Blom, Bakker, Blanker, Daams, Everdij and Klompstra [1]. Whereas this approach mainly focuses on the analysis of existing accidents (also called accident analysis or retrospective analysis), the current paper also addresses analysis of potential future accidents (called risk analysis or prospective analysis). This is done by means of a multi-agent simulation framework that addresses both the behaviour of individual agents (operators, pilots) as well as their mutual communication, and interaction with technical systems. By manipulating various parameters in the model, different scenarios can be explored. Moreover, by means of automated checks of dynamic properties, these scenarios can be assessed with respect to their likelihood of the occurrence of accidents. The approach is illustrated by a case study on a runway incursion incident at a large European airport in 1995. 

The runway incursion incident took place during the departure of an Airbus A310 of a civil aviation company from one large airport in Europe. A summary of the scenario is provided below. A schematic overview of the situation is provided in Fig. 1. 

Fig. 2. Formalised empirical trace of the runway incursion incident in LEADSTO.

H8. An aircraft enters a runway for which it does not have a clearance (called runway incursion). 

It is also possible that we have simply not yet seen the full safety impact of deregulation. Reduced safety margins (indicated, for example, by increased rates of near midair collisions and runway incursions Oster et al., 1992), in combination with an aging aircraft fleet, may still lead to more significant safety... 

Two individuals noted that deregulation had increased the numbers of airplanes in the air, and hence the amounts of traffic being handled by the air traffic control system. One of these specifically suggested that this might be a factor in altitude deviations and runway incursions, and emphasized that communications is one of the most frequent causes of accidents in the industry. This individual also noted that in the first 10 years after deregulation, neither the new airlines nor the FAA were fully prepared to deal... 

This paper gives an overview of performing safety risk assessment of a safety critical operation with support of Monte Carlo (MC) simulation. The approach is outlined for an air traffic example involving aircraft departing from a runway, which is occasionally crossed by taxiing aircraft. At the airport considered, a Runway Incursion Alert System (RIAS) is installed to warn the air traffic controller in case of impending runway incursions. The paper explains the key issues to be mastered in performing a MC simulation supported safety risk assessment of this kind of operation. 

The runway A controller visually monitors the traffic and has support from a stopbar violation alert and a runway incursion alert. If the controller is aware that a taxiing aircraft has passed the stopbar, a hold clearance is given to both taxiing and taking off aircraft. Further details of the runway controller model are given by (Stroeve et al.,2003). 

The model of the radar surveillance system represents position and velocity estimates for both aircraft. There is a probability that radar surveillance is not available, resulting in track loss. Radar surveillance data is used as basis for ATC stopbar violation alerting and ATC runway incursion alerting. 

Two types of ATC alerts are included in the model a stopbar violation alert and a runway incursion alert. A stopbar violation alert is presented to the controller if surveillance data indicates that an aircraft has passed an active stopbar. There is a probability that the stopbar violation alert system does not function, implying that there will be no alert. A runway incursion alert is presented to the controller if radar surveillance data indicates that the taxiing aircraft is within a critical distance of the runway centre-line and the taking-off aircraft has exceeded a velocity threshold in front of the runway crossing. There is a probability that the runway incursion alert system does not function, implying that there will be no alert. 

It follows from a comparison of cases 1 and 5 that in the normal situation that all human operators are actively monitoring, ATC alert systems (runway incursion or stopbar violation) have a modest effect on the achieved risk. 

Once identified, the specific human factor risk will need to be analysed as well as managed and mitigated. Typically this will involve a more detailed assessment of the risk, and a systemic review or systemic investigation will be imdertaken, involving a qualifiedHF expert, in addition to subject matterexperts as required. Example reviews of this type include a Systemic Review of Breakdown of Separation Occurrences, a Review of Pilot Violations of Controlled Airspace, and ongoing reviews of both Runway Incursion Incidents and Pilot Operational Deviations. 

Harrison, M. J. Runway Incursions and Airport Surface Traffic Automation. SAE (Society of Automotive Engineers) Transactions 100 (1991) 2423-2426. 

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