The strong reduction of air traffic during the COVID-19 pandemic provides a unique test case for the relationship between air traffic density, contrails, and their radiative forcing of climate change. Here, air traffic and contrail cirrus changes are quantified for a European domain for March to August 2020 and compared to the same period in 2019. Traffic data show a 72 % reduction in flight distance compared with 2019. This paper investigates the induced contrail changes in a model study. The contrail model results depend on various methodological details as discussed in parameter studies. In the reference case, the reduced traffic caused a reduction in contrail length. The reduction is slightly stronger than expected from the traffic change because the weather conditions in 2020 were less favorable for contrail formation than in 2019. Contrail coverage over Europe with an optical depth larger than 0.1 decreased from 4.6 % in 2019 to 1.4 % in 2020; the total cirrus cover amount changed by 28 % to 25 %. The reduced contrail coverage caused 70 % less longwave and 73 % less shortwave radiative forcing but, because of various nonlinearities, only 54 % less net forcing in this case. The methods include recently developed models for performance parameters and soot emissions. The overall propulsion efficiency of the aircraft is about 20 % smaller than estimated in earlier studies, resulting in 3 % fewer contrails. Considerable sensitivity to soot emissions is found, highlighting fuel and engine importance. The contrail model includes a new approximate method to account for water vapor exchange between contrails and background air and for radiative forcing changes due to contrail–contrail overlap. The water vapor exchange reduces available ice supersaturation in the atmosphere, which is critical for contrail formation. Contrail–contrail overlap changes the computed radiative forcing considerably. Comparisons to satellite observations are described and discussed in a parallel publication.

Significant efforts are underway to modernise global air traffic management systems. This will result in a level of connectivity between different systems that has never before been achieved, creating a `system of systems' that requires a very high level of dependability. To achieve this dependability, security must be designed-in rather than relying on hardening of systems post implementation. This is also expected to minimise the costs of security. The European ATM modernisation programme, SESAR, has been taking a systems engineering approach to ensure that R&D is rapidly transferred to industrialisation and then deployment. This approach has been applied to security, organised around `operational focus areas' that represent discrete operational improvements. In such a complex programme, traditional risk analysis and mitigation was thought to be limited when attempting a system wide coherence for security. Hence the SESAR programme is adopting a `security case' approach, drawing on lessons learned in safety cases, validation & verification of ATM R&D, and aligned to the system engineering approach.

This paper is concerned with the design of a distributed aviation security situation management capability in SESAR and NextGen. This research-in-progress report presents an approach to distributed situation management based on the concepts of network-centric operations and agent-based modeling. In particular, One of the key issues in aviation security is that despite their catastrophic magnitude, incidents are rare and their precursors hard to identify. The anticipated growth of aviation will increase this challenge as the amount of air traffic will double by 2025, and the future ATM System will see a higher integration of manned and unmanned air vehicles with significantly different capabilities to interact with on-board situations. We envision a highly integrated air transportation system and the capability to process relevant situational information elements. The described situation management problem is modeled as a multi-agent information problem. Situation management is viewed as an emergent property of collaborative systems including both human operators and technological agents. This paper addresses the challenges and conceptual modelling of an agent based simulation of the future aviation and air traffic management environment. The results obtained indicate that automated support for situation management in aviation security is feasible and capable of supporting distributed information sharing and early identification of incidents. Also of importance is that this capability will not place additional constraints on the future ATM System as it can be designed as a data service of the envisaged system-wide information management infrastructure.

Air Traffic Management (ATM) could benefit from a collaborative approach to security management, particularly to improve situational awareness, quantitative risk assessments and the governance of security. Collaboration between organisations is becoming increasingly important in air traffic control as well as security in general. This emphasises the need to adapt security cultures from 'need to know' towards more direct sharing of knowledge and skills. An additional imperative for the air traffic management sector is that as operations and systems become increasingly integrated, Air Navigation Service Providers (ANSPs) become critically dependent on each other. Hence security of the organisation is bound with the security of the whole European system. To create a successful collaborative approach, security managers will need to adopt collaborative leadership skills and approaches. This can be achieved in an evolutionary way, which grows as the challenges to security become more demanding and complex, as the ATM system is modernised.

Significant efforts are underway to modernize global air traffic management systems. Flight efficiency is a major political design criterion. This paper addresses the identification and measurement of ATM related constraints on vertical flight efficiency with a focus on continuous descent operations. Efficiency of flight operations has become a key driver for identifying bottlenecks and constraints imposed by ATM on airspace user preferred flight trajectories. In particular, measures aiming at fuel-efficient operations attract a lot of attention. This paper reports on the work jointly performed by the FAA and EUROCONTROL to address vertical flight efficiency. Based on an empirical study of trajectory data for US and European airports, a vertical profile analysis algorithm has been developed considering research experiences and stakeholder consultations of both teams. This work was performed as the preparatory action of the joint US/Europe comparison report. The results include a joint and harmonized algorithm to describe the vertical trajectory profile and the initial definition of metrics for the performance measurement. This harmonized algorithm will be further be validated and refined as part of the US/Europe comparison report including a wider set of airports. Demonstrating the general feasibility, the algorithm will be further promoted for use in international performance activities under ICAO.

Cyber Security Incident Management is an emerging paradigm and capability within the aviation domain. To date, limited research has addressed the requirements and developed tangible solutions for the deployment of such a capability. This paper leverages good practice and experiences from other critical infrastructure settings in order to sketch a recommendation for cyber incident response management for the aviation domain.