Identification of causes of the delays within transition airspace is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Services: without knowing the current performance levels, it is difficult to identify which areas could be improved. Inefficient vertical profiles within TMA and deviations from the optimal flight paths due to bad weather conditions are the main sources of performance decline. In this work, we analyse punctuality and vertical efficiency of Stockholm Arlanda airport arrivals, and seek to quantify the fuel consumption impact associated with the inefficient vertical flight profiles within the Terminal Maneuvering Area (TMA).We use Opensky Network data for evaluation of the Stockholm Arlanda airport performance, comparing it to the DDR2 data provided by Eurocontol, outlining the advantages and disadvantages of both.