The aviation industry faces the urgent challenge of reconciling projected traffic growth with stringent climate targets, including the European Union’s goal of climate neutrality by 2050. While techno-logical innovations such as sustainable aviation fuels and hydrogen propulsion are critical for long-term decarbonization, their near-term impact remains limited. In this thesis, we address the immediate opportunity of improving the environmental efficiency of aircraft arrival operations in Terminal Manoeuvring Areas (TMAs), where congestion and complex sequencing often lead to excess fuel burn, emissions and noise.

Existing research has demonstrated the benefits of Continuous Descent Operations (CDOs) and structured arrival procedures such as Point Merge (PM). However, for TMA performance evaluations, cur-rent practices are limited in real-world assessments of environmental efficiency beyond Carbon Dioxide (CO2). In terms of optimization of the arrival operations, the exploration of dynamic PM usage and early speed adjustments as a sequencing tool, integrated within the optimization framework, remains relatively unexplored. Furthermore, most optimization frameworks do not fully integrate arrival and departure scheduling in mixed-mode runway environments.

The thesis addresses four key research questions: (1) What are the environmental benefits of using fuel-efficient CDOs within TMA and how to quantify them? (2) How to evaluate the arrival aircraft performance within TMAs implementing PM procedures? (3) Can the performance of current operations in a TMA where PM is implemented be improved by using optimization? (4) How can speed adjustment during cruise and descent be used, with or without combining it with PM procedures, to safely separate and sequence arriving flights? The overarching aim is to develop methodologies for assessing and optimizing arrival operations to reduce fuel consumption, emissions and noise while maintaining safety and capacity.

The research combines data-driven performance evaluation with mathematical optimization. We use real-world Automatic Dependent Surveillance Broadcast (ADS-B) trajectory data from the OpenSky Network, together with meteorological data from ECMWF ERA5 and the performance modeling capabilities of EUROCONTROL BADA, to quantify inefficiencies in current operations. For optimization, we develop a Mixed-Integer Programming (MIP)-based framework to assign conflict-free, fuel-efficient arrival routes and descent profiles, incorporating wake turbulence separation and runway scheduling constraints. We perform case studies at Dublin and Oslo-Gardermoen airports, both operating with PM procedures.

Empirical analysis reveals substantial inefficiencies in current TMA operations, with level-flight segments contributing significantly to excess fuel burn. Our studies show that CDOs reduce fuel consumption and noise exposure, although Carbon Monoxide (CO) and Hydrocarbon (HC) emissions may increase under idle-thrust conditions. Optimization results demonstrate that dynamic PM usage and early speed adjustments improve horizontal and vertical efficiency, reduce time in TMA and decrease fuel burn compared to actual operations.

Operational improvements in arrival management can deliver immediate environmental benefits, complementing long-term technological solutions. The proposed frameworks support SESAR and NextGen objectives for greener TMAs and are adaptable to future contexts, including Urban Air Mobility (UAM). By integrating rigorous performance evaluation with advanced optimization, this thesis provides actionable insights for reducing aviation’s environmental footprint while enhancing predictability.

Flygindustrin står inför den akuta utmaningen att förena prognostiserad trafikökning med strikta klimatmål, inklusive EU:s ambition om klimatneutralitet till år 2050. Även om tekniska innovationer såsom hållbara flygbränslen och vätgasdrift är avgörande för långsiktig avkarbonisering, är deras kortsiktiga effekt begränsad. Denna avhandling adresserar den omedelbara möjligheten att förbättra den miljömässiga effektiviteten bland ankommande flygplan inom terminalområden (TMA), där trängsel och komplex sekvensering ofta leder till ökad bränsleförbrukning, utsläpp och buller.

Tidigare forskning har visat fördelarna med Continuous Descent Operations (CDOs) och strukturerade ankomstprocedurer såsom Point Merge (PM). För utvärdering av TMA-prestanda är dock nuvarande metoder begränsade när det gäller studier av miljöeffektivitet bortom koldioxid (CO2). Vid optimering av ankomstoperationer ¨ar användningen av dynamisk PM och tidiga hastighetsjusteringar som sekvenseringsverktyg, integrerade i optimeringsramverket, relativt outforskat. Dessutom saknar de flesta optimeringsramverk en fullständig integrering av ankomst- och avgångsschemaläggning i miljöer med blandad bananvändning.

Avhandlingen behandlar fyra centrala forskningsfrågor: (1) Vilka är de miljömässiga fördelarna med bränsleeffektiva CDO:er inom TMA och hur kan de kvantifieras? (2) Hur kan prestandan för ankommande flygplan i TMA med PM-procedurer utvärderas? (3) Kan prestandan för nuvarande operationer i ett TMA med PM förbättras genom optimering? (4) Hur kan hastighetsjustering under marsch och sjunk användas, med eller utan kombination med PM, för att säkert separera och sekvensera ankommande flyg? Det övergripande målet är att utveckla metoder för användning till att utvärdera och optimera ankomstoperationer, för att minska bränsleförbrukning, utsläpp och buller, samtidigt som säkerhet och kapacitet bibehålls.

Forskningen kombinerar datadriven prestandautvärdering med matematisk optimering. Vi använder verkliga ADS-B-flygdata från OpenSky Network, meteorologiska data från ECMWF ERA5 samt EUROCONTROL:s BADA-modell för att kvantifiera ineffektivitet i nuvarande operationer. För optimering utvecklar vi ett Mixed-Integer Programming (MIP)-baserat ramverk för att tilldela konfliktfria, bränsleeffektiva inflygningsvägar och sjunkprofiler, med hänsyn till separation på grund av turbulens från vingspetsvirvlar och begränsningar i banschemaläggning. Fallstudier genomförs vid Dublin och Oslo-Gardermoen, båda med PM-procedurer.

Empiriska analyser visar betydande ineffektivitet i nuvarande TMA-operationer, där planflygsegment bidrar avsevärt till ökad bränsleförbrukning. Våra studier visar att CDO:er minskar bränsleförbrukning och bullerexponering, även om utsläpp av kolmonoxid (CO) och kolväten (HC) kan öka vid motortomgång. Optimeringsresultaten visar att dynamisk PM-användning och tidiga hastighetsjusteringar förbättrar både horisontell och vertikal effektivitet, minskar tid i TMA och reducerar bränsleförbrukning jämfört med faktiska operationer.

Operativa förbättringar i ankomsthantering kan ge omedelbara miljöfördelar och komplettera långsiktiga tekniska lösningar. De föreslagna ramverken stödjer SESAR- och NextGen-målen för grönare TMA och är anpassningsbara till framtida kontexter, inklusive Urban Air Mobility (UAM). Genom att integrera rigorös prestandautvärdering med avancerad optimering ger denna avhandling handlingsbara insikter för att minska flygets miljöpåverkan och samtidigt förbättra förutsägbarheten.

We consider the computation of dynamic arrival routes (DARs): arrival routes from all entry points of a terminal maneuvering area that merge traffic arriving in a given time interval towards the runway for which we can guarantee separation for all arriving aircraft and enable all aircraft to follow optimal descent profiles. We exploit our recent mathematical results to bring the concept of DARs closer to practical applicability by demonstrating how we can integrate both the impact of atmospheric conditions on the aircraft’s descent profiles and the interaction with departing traffic into our DARs framework. With experimental results for Stockholm Arlanda airport, we give a proof of concept of this integration—showing that we can quickly obtain optimal solutions—and highlight the importance of these aircraft-specific and traffic-situation-dependent factors.

We present an application of a mixed-integer programming (MIP) framework for automatic traffic synchronization, providing safe separation between the arriving traffic within the terminal maneuvering area (TMA) of an airport implementing point merge (PM) procedures. Additionally, the proposed methodology ensures conflict-free operations when departures and arrivals share a common runway. Based on real traffic scenarios for two European airports, we model realistic descent profiles and assume all the arrivals are performing the most fuel-efficient continuous descent operations (CDOs). We compare two scenarios: in the first, the arriving aircraft are strictly forced to adhere to the published arrival route structures, meaning that a turn towards the merge point may not be initiated prior to reaching the point merge system (PMS), while in the second scenario, aircraft may be assigned a shortcut from a published waypoint along the arrival route. We evaluate the resulting arrival flight efficiency and compare it to that of the actual flights, arriving during the hour selected for our optimization, noticing varying benefits for the two airports and whether shortcuts are allowed or not. Given the correct setting for the specific airport, we demonstrate that our approach provides significant benefits, including increased vertical performance as well as reduced time and distance, contributing to lower levels of noise and fuel savings, accompanied by reduced emissions.

The transportation sector, accounting for about one fifth of all greenhouse gas emissions, is facing a significant transformation in order to become more climate-friendly. In terms of air transportation, there are several important steps on the way to making flying sustainable both for the planet itself and for people directly or indirectly being exposed to its effects. In the state of the current air traffic operations, where environmentally friendly propulsion systems and fuels are not yet implemented on a large scale, enhancing the efficiency in the airspace can help to bring us closer to the environmental goals of aviation. Such solutions may include improved synchronization of arriving flights in the Terminal Maneuvering Area (TMA), in which congestion is a problem for many airports.  

In this thesis, we first explore and develop methodologies for assessing the environmental impact of the operations in TMA. More specifically, the goal of the assessments is to quantify the additional fuel consumption, gaseous emissions and noise that comes from horizontally and vertically inefficient arrival operations in TMA. We perform our assessments on a couple of European airports, including Stockholm-Arlanda.   

Secondly, we propose a Mixed Integer Programming (MIP)-based optimization model which provides for conflict-free arrival operations, where aircraft fly fuel-efficient Continuous Descent Operations (CDOs), applied to Point Merge (PM) arrival procedures, with the primary purpose to serve as a route assigner. We base our optimization on real scenarios, from actual transmitted flight data, and model realistic descent profiles considering the operational capabilities of the specific aircraft type. Additionally, the optimization model ensures the required spacing between aircraft taking off and landing in case the runway is used in a mixed mode. We evaluate our solutions by assessing numerous performance metrics, including environmental efficiency, and compare to the actual trajectories of the real operations. On two European airports implementing PM procedures, we demonstrate that our optimization model provides improved vertical performance as well as reduced time and distance flown in TMA, contributing to reduced levels of noise and fuel savings, accompanied by decreased emissions. 

The number and diversity of space and higher-airspace missions is rapidly growing worldwide, including Europe. However, the prosperity of these new entrants may become incompatible with that of the conventional aviation, unless their coexistence is regulated. Since “what gets measured gets managed”, the impact on the conventional air traffic needs to be evaluated. To that end, we conduct a literature review and propose a methodology to quantify the impact that a real, segregated, special operation within a vertically unlimited volume had on regular air traffic. This methodology is then applied to a recent disruptive event in southern Europe.

Point Merge (PM) arrival procedure is implemented at multiple airports around the World. There aredifferent PM design variants: with overlapping, partially overlapping or separated sequencing legs, aposition of the sequencing legs inside or outside the TMA, different geometry of the flows to PM ormerging to a point; each coming with a different impact on the trade-offs associated with the structure.

In this work, we investigate the usage of PM procedures in several airports around the globe using open-access ADS-B-based data provided by the OpenSky Network. We analyse arrival flows at the airports with

PM, and propose a catchment algorithm to see which flights from the blend are actually adherent to theprocedure. Then quantify the PM utilization by applying the performance indicators specifically designedfor this purpose.

The paper focuses on the performance assessment of the arrival operations in Oslo Gardermoen airport implementing point merge (PM) procedures. We take a data-driven approach based on the open-source ADS-B data, and conduct a detailed performance assessment utilizing a diverse set of performance indicators, including newly developed metrics for better understanding of the PM specifics. The results of the performance evaluation indicate that the PM systems are currently underutilized in Oslo airport, and their increased usage may lead to the improved arrival performance, especially during the peak time periods.