Xavier Prats Menéndez

Enhancement of a time and energy management algorithm for continuous descent operations

In previous research, an aircraft trajectory planning algorithm was developed aiming at optimizing continuous descent operations with required times of arrival at given waypoints. A non-linear optimal control problem was solved by using direct transcription methods. In this paper, enhanced models for the same optimization framework are presented, im- proving the accuracy of the optimized trajectories. These new models take into account wind, realistic atmospheric conditions, curved trajectories and general improvements in the aircraft dynamics model. Preliminary results are shown in a hypothetical scenario where trajectories are optimized from cruise altitude to the runway with different required times of arrival at the threshold. The effects of wind and non-standard atmospheres can be easily appreciated.

Fligth dispatching for unmanned aerial vehicles

Flight dispatching is the set of tasks related to flight preparation, such as load and balance, meteorology study and briefing, operational flight planning, contingency analysis and planning, etc. The flight dispatcher must be in close contact with the pilot in command in order to verify that the airplane is airworthy, furnishing all kinds of information needed to properly operate the system. The advent of Unmanned Aerial Vehicles (UAVs) operating on civil missions will require developing new dispatching processes that take into account the main role of these vehicles: the mission. Traditional aviation focuses on point to point transportation of passengers and/or cargo. However, UAVs usually focus on surveillance applications that require large sets of sensors and complementary avionics to properly develop their assigned task. This paper presents the design of a new dispatching methodology focused for UAV civil applications. The overall process is mission-centric, focusing on all the requirements needed to properly implement the assigned tasks, but also integrating the traditional dispatching requirements of manned aircraft. The proposed dispatching process is built upon a specific UAV mission architecture, the Unmanned Service Architecture (USAL). Based on this architecture a methodology is introduced to characterize the mission objectives, the UAV airframe and its various characteristics, the software services required for managing the flight and the mission, the sensor and computational payload, etc. All these elements are combined together in an iterative dispatching flow. The result of the process is the actual UAV configuration in terms of fuel, electrical system, payload configuration, flight plan, etc; but also detailed flight plan, alternative routes and landing sites, detailed USAL service architecture and even contingency planning.

Effectiveness of Problem Based Learning for Engineering Curriculum

The main purpose of this paper is to describe the process by which an initially limited-range practical experience, within the frame of a given subject in an aerospace engineering degree, might be expanded to become the mother-subject itself. Particularly, the practical experience is a Model Rocket Workshop (MRW), where students design, simulate, build, test and launch a small model rocket. The workshop is a Problem Based Learning (PBL) experience that covers a wide spectrum of educational aspects, ranging from theoretical disciplines, such as fluid dynamics and rocket dynamics, to topics more related to experimental work and hardware utilization like the certification of the rockets, as well as the rocket altitude measurements. Students get rapidly involved in the project, and acquire several practical and transversal abilities, while developing a solid knowledge of the physics underlying aerospace engineering. The case study shows some problems and improvements, academic results and lessons learned from the PBL approach. Finally, a series of new ideas related to MRW and the subject it belongs to are presented. The objective is to expand the MRW so that it embraces the totality of the activities that constitute this mother-subject. As a consequence, the former would then become a new subject entirely based on PBL. The strategy aims at enabling an optimum transition from conventional learning to PBL.Cases on Technological Adaptability and Transnational Learning: Issues and Challenges contains case studies on divergent themes of personalized learning environments, inclusive learning for social change, innovative learning and assessment techniques, technology and international partnership and transnational collaboration for enhanced access under the core domain of technological adaptability and transnational learning.

Combining the assignment of pre-defined routes and RTAs to sequence and merge arrival traffic

Continuous descent operations (CDO) with required times of arrival (RTAs) have been identi ed as a potential solution to reduce the environmental impact without compromising capacity. However, in high traffic scenarios RTAs may not suffice to maintain safe separa- tion, and air traffic controllers may still need to use

Including linear holding in air traffic flow management for flexible delay handling

This paper introduces a strategy to include linear holding into air traffic flow management initiatives, together with the commonly used ground holding and airborne holding measures. In this way, f...

Optimization of the vertical trajectory through Time and Energy management: A Human-in-the-Loop Study

A new on board integrated planning and guidance concept has been developed that attempts to optimize the vertical trajectory to achieve a continuous engine-idle descent while satisfying time constraints. The new concept, named Time and Energy Managed Operations (TEMO), reduces noise, gaseous emissions and fuel consumption, while adhering to time constraints yielding control points for aircraft spacing and sequencing. The concept allows small deviations between planned and actual trajectory within pre-set boundaries and calculates a new trajectory when these deviations are exceeded. The concept was evaluated in a Full Motion Flight Simulator at the premises of the National Aerospace Laboratory (NLR) in Amsterdam. Six pilots were invited to provide feedback of the TEMO concept with respect to operation, safety and certification requirements and to demonstrate that the TEMO Technology Readiness Level (TRL) achieved level 5, in that the technology is demonstrated in a relevant (simulated) environment. Conclusions drawn from the responses to the questionnaires and any issues that have emerged indicate that TEMO is a promising concept that may play a valuable role in ATM facilitation. Recommendations for future research include the use of more involved scenarios and active participation of ATC.

Requirements, issues, and challenges for sense and avoid in Unmanned Aircraft Systems

The sense and avoid capability is one of the greatest challenges that has to be addressed to safely integrate unmanned aircraft systems into civil and nonsegregated airspace. This paper gives a review of existing regulations, recommended practices, and standards in sense and avoid for unmanned aircraft systems. Gaps and issues are identified, as are the different factors that are likely to affect actual sense and avoid requirements. It is found that the operational environment (flight altitude, meteorological conditions, and class of airspace) plays an important role when determining the type of flying hazards that the unmanned aircraft system might encounter. In addition, the automation level and the data-link architecture of the unmanned aircraft system are key factors that will definitely determine the sense and avoid system requirements. Tactical unmanned aircraft, performing similar missions to general aviation, are found to be the most challenging systems from an sense and avoid point of view, and further research and development efforts are still needed before their seamless integration into nonsegregated airspace.