Impact of Volcanic Ash on European Air Traffic: Simulated Eruption of Volcano Stromboli

Title: Impact of Volcanic Ash on European Air Traffic

Subtitle: Simulated Eruption of Volcano Stromboli

Keywords: Volcanic Ash; Air Traffic Management; Safety; Symulation

INTRODUCTION

The current regulatory situation in Europe is that flying in forecasted, differently contaminated volcanic ash zones is allowed as long as airlines have their specific Safety Risk Assessment (SRA) approved. This regulation has the goal to reduce adverse impact that volcanic ash ejected in the atmosphere has on air traffic management (ATM). There are three different types of SRAs and it is, however, not yet clear what effects on air traffic operations each type eventually has. Therefore, in this contribution, we concentrate on in depth analysis of those effects. We treat the European airspace as airspace with harmonized, unique regulatory setup that recognizes the approach to volcanic ash issue based on SRA, even though some European States still do not comply with this approach and close their airspace in case of airborne volcanic ash.

Additionally, we introduce a novel approach to the volcanic ash issue and analyze its effects on operations. This approach: (i) always designates volcanic ash issue as a crisis situation and therefore (ii) implies opening of previously defined restricted zones for traffic. Hence, this approach alludes the willingness of European States to relinquish any portion of airspace that would in standard situation be planned for activities requiring designation of that airspace as restricted to civil air traffic (regular military exercises, probation of flying over national parks etc.).

BACKGROUND

To analyze the effects of two approaches on operations, the specific traffic scenarios over Europe are designed and related to the simulated eruption of Stromboli volcano (Aeolian Islands, Italy). This simulated eruption is created by the organization committee of the ICAO's regular volcanic ash exercise (VOLCEX14/01) in the EUR and NAT Regions. An analysis of impact on sector capacity and traffic flow is performed with the fast-time simulation (FTS) tool.

METHODOLOGY

- Analyzed Day

The exercise VOLCEX14/01 simulates different directions of movements and areas covered by low, medium and high concentration of volcanic ash during 1st and 2nd April 2014. Due to the fact that the pattern of the ash cloud is much more spread out on the second day, the 2nd April 2014 is the day chosen for the analysis.

- Volcanic Ash and Air Traffic Data

These data are acquired from the Volcanic Ash Advisory Centre (VAAC) Toulouse and EUROCONTROL. The VAAC Toulouse provides sets of CSV data files containing forecasts of volcanic ash in three different concentration zones and height ranges. The validity period of each set is six hours. The EUROCONTROL provides the air traffic data for the period of 24 hours. The data comprise number of flights entering in the Central Flow Management Unit (CFMU) area. In total, around 27,000 flights are simulated.

- Generation of Specific Traffic Scenarios

Following the methodology developed in one of our previous investigations, the specific traffic scenarios are designed. We thus locate Stromboli volcano in the southern traffic region and observe the traffic flows following the north-southeast (N-SE) and the southeast-southwest (SE-SW) axes. Traffic flow following the north to southwest (N-SW) axis is not considered as volcanic ash ejected in this eruption affects only southern parts of Europe.

- Analyzed Types of SRA

Firstly, we look into the number and types of SRAs approved in Europe. Based on gained results we make a decision to analyze only effects posed by the approaches defined within SRAs that allow operations in areas forecasted to be contaminated with low ash concentration, as well by the approaches defined within SRAs that allow operations in areas forecasted to be contaminated with low and medium ash concentration. The SRAs that allow operations in areas forecasted to be contaminated with low, medium and high ash concentration are omitted from the investigation as they are presented in less than 2% of the analyzed cases.

- Definition of European Restrected Zones

A few generic restricted zones in the vicinity of simulated volcanic ash cloud from Stromboli volcano are designed. The generic restricted zones are introduced in order to allow analysis of the airspace anticipated to be the most affected by the ash cloud movements. The restricted zones' horizontal size is 1 × 2.5 degrees on a latitude/longitude array. There is no vertical subdivision applied.

RESULTS AND DISCUSSION

The following results are presented in order to discuss effects of two approaches on air traffic operations:

- posed number and duration of conflict with volcanic ash cloud when different SRA is applied

- proposed optimized flight trajectories around the areas of specific ash concentration and its characteristics

- capacity analysis of the air traffic control (ATC) sectors estimated to be more affected by the necessity of rerouting around the areas of contamination

- workload of the controllers responsible for providing services in those ATC sectors.

AIM OF THE RESEARCH

The investigation done could be of interest in terms of incentive for scientific and industrial community to define a safe dose of volcanic ash which could further lead to the harmonized State approach to the volcanic ash problem and better exploitation of airspace while maintaining safety. Nevertheless, we would like to emphasize that undertaken analysis takes into account simulated volcanic eruption and that further analysis taking into account realistic explosive eruptions (especially the latest ones) are highly required for an utter understanding of the issue.