Pushback collision prevention system (pushback COPS)
Because of the restricted space at aprons ground operations require a lot of attention and care by the participants to prevent accidents and incidents at airports. Furthermore ground operations are characterized by time pressure and high traffic density. The pushback as part of ground operations takes place under unfavorable circumferential visibility conditions additionally. That’s why the tug driver needs experience and ability to push the aircraft safely within the given narrow passageway to the target taxiway/taxilane. An investigation of pushback accidents and incident at U.S. airports from 1991-2011 shows that collisions during pushback operations are more frequent as assumed. Hence, an appropriate system support promises a safety benefit and also a capacity benefit especially in case of weather caused bad visibility conditions. The pushback collision prevention system, which will be developed, should present the position and dimension of the pushed aircraft and the situation regarding the potential, (for now) fixed obstacles. Furthermore the safe maneuvering corridor, the ideal trajectory and the risk of a collision with an object should be displayed in a proper way. It suggests itself, that the tug driver will use the support system primarily. But taking into account the possibility of an autonomous leaving of the aircraft from the aircraft stand (e.g. by etaxiing), the system support of the pushback could be also interesting for a future using by the flight crew.
Specific research activities in the context of pushback CoPS
Pushback process times depending on the aircraft stand at the apron of the airport Dresden, Germany (in Ingenieursspiegel, 01/2013)
The pushback process is almost similar in its fundamental facets of the procedural and technical operations. But in detail the process differs in such a way, that a worldwide standard procedure does not exist. But standardization could help to minimize the variance of pushback process times. Weather caused visibility and surface conditions and also the given obstacle environment influence pushback operations and especially the process times furthermore, like an analysis of pushback process times at the Dresden airport, Germany shows. These results provide an improved prediction of ground handling times and are interesting in the context of the research project dynamic process optimization.
Up to now the A-SMGCS concept and related researches and developments do not consider the pushback process, which is part of the taxi-out process and therefore also part of the gate-to-gate-process. Coupling with an appropriate support system this identified gap of the desired future visibility-independent gate-to-gate-process could be closed.
Publikationen
- H. Fricke, M. Schultz, F. Dieke-Meier, T. Kunze and B. Oreschko (2013). Efficient handling process management in consideration of stochastic planning deviations, Ingenieurspiegel, 01/2013 (in German)
- F. Dieke-Meier and H. Fricke (2012). Expectations from a steering control transfer to cockpit crews for aircraft pushback, International Conference on Application and Theory of Automation in Command and Control Systems (ATACCS), London
- Uwe Pollack (2011). Development of a procedural concept for the pushback and taxi process using new technical system solutions, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
- Jan Keller (2010). Investigation of the dependencies of the pushback process times on external weather caused factors and on pushback procedures, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
Pushback collisions and related accident/incident rates at U.S. airports, 1991-2011 (in Proc. ATACCS 2013)
Fortunately pushback occurrences result often in minor damages of aircraft, especially compared to occurrences during flight operations. Nevertheless these damages represent economic losses, which are remarkable because of their financial strain and their frequency. Because of that, the lacking notice of research and industry for the problems is inexplicably. Only few studies concern themselves with pushback risks, but often indirectly and almost with a focus on the risk of (fatal) injuries of pushback assisting personnel exclusively. Hence, one of the research activities in the context of Pushback CoPS deals with the evaluation of the safety of the current implemented pushback procedures. The results of a deterministic accident/incident analysis (at U.S. airports from 1991-2011) show an urgent necessity to organize safer pushback operations. For instance, the determined fatal accident rate violates the formal defined A-SMGCS Target Level of Safety of 1E-08 accidents per ground operation.
The 189 identified pushback-related occurrences are distinguished regarding their safety effects in four categories:
- Category 1: Damage to/by pushed aircraft (A/C) caused by a collision with other moving/pushed, stationary aircraft (A/C) or fixed objects
- Category 2: Damage to/by pushed aircraft to/by tug or towbar
- Category 3: Damage to pushed aircraft by apron equipment or ground vehicle (except tug or towbar)
- Category 4: Ground/aircraft crew injuries and fatalities during pushback.
Especially the increasing rate of collisions between the pushed aircraft and objects (category 1 occurrences) motivates a development of a pushback collision prevention system.
Publications
- F. Dieke-Meier, T. Kalms, H. Fricke and M. Schultz (2013). Modeling aircraft pushback trajectories for safe operations, International Conference on Application and Theory of Automation in Command and Control Systems (ATACCS), Naples
- F. Dieke-Meier and H. Fricke (2012). The need for a collision prevention system for the pushback of aircraft, International Council of the Aeronautical Sciences (ICAS), Brisbane
- György Szilagyi (2012). Development and implementation of a model to reproduce jet blast hazards at aprons, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
- Jana Ludwig (2011). Investigation of the impacts of jet blast in consideration of the display development for safe pushback operations, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
- Stefanie Hahn (2010). Investigation to derive a target level of safety for the pushback process at an apron, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
Exemplary pushback maneuver (in Proc. ATACCS 2013)
The prediction and assessment of possible hazard situations during pushback operations need a representation of the aircraft movement as a pushback trajectory. Compared to other ground based air traffic simulation minimal distances from aircraft to objects at the apron require exact information about the aircraft position and potential obstacles. To model aircraft movements exactly (especially the case of the aircraft tractrix), two aircraft reference points and/or related trajectories are necessary: the trajectory of the nose gear and the trajectory of the main gear. Based on a kinematic approach a pushback trajectory model is developed and will be validated. Furthermore, an algorithm will be developed to identify the ideal trajectories, in terms of minimal collision risks.
Publikationen
- F. Dieke-Meier, T. Kalms, H. Fricke and M. Schultz (2013). Modeling aircraft pushback trajectories for safe operations, International Conference on Application and Theory of Automation in Command and Control Systems (ATACCS), Naples
- Thomas Kalms (2012). Implementing and validating of an on-time model to reproduce aircraft movements during pushback, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
- Stefan Böhm (2010). Development of a model to reproduce aircraft taxi and pushback movements at aprons, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
The narrow maneuvering corridor of pushback operations requires very exact on time positioning data to achieve a high safety level and acceptance of the user. For this, requirements to the technical components (systems, sensors, communication technologies) will be identified and currently existing technical solutions will be investigated regarding their ability for determining the position of the aircraft/tug and (moving) obstacles.
Publications
- Matthias Beck (2012). Modeling of the system characteristics of the communication technology WiMAX to prove its using for a system supported pushback of aircraft, TU Berlin/TU Dresden (in German)
- Thomas Kalms (2010). Modeling of the INS/IRS system error as aircraft position deviation while taxiing at the apron, Chair of Air Transport Technology and Logistics, TU Dresden (in German)
- See also research project Analysis of 3D point cloud surveillance for an effective risk mitigation on airport aprons