Development Of Requirements For Aeronautical Studies Assessing Obstacles

The International Civil Aviation Organization (ICAO) regulations defined in Annex 14 specify airspace around aerodromes to be maintained free from obstacles. For that purpose, virtual surfaces called “Obstacle Limitation Surface” (OLS) are described, which ideally shall not be penetrated by an object. Nevertheless – according to ICAO, EASA and many states – penetrations may be acceptable if an “aeronautical study” demonstrates that the object or obstacle has no adverse impact on the safety or regularity of flight operations. This process generally requires a specialised third-party – as airsight – to develop the aeronautical study, which shall be later submitted and reviewed by the responsible aviation authority.

Nevertheless, while this practice is very common in many countries, it is well-known that there is a lack of detailed regulations and guidance material for conducting aeronautical studies for assessments of objects penetrating the Obstacle Limitation Surface (OLS) of an aerodrome. General guidelines exist for conducting a more generic “safety assessment” – but these do not provide any details about assessing physical obstructions. Some states define “aerodrome safeguarding principles” to monitor obstacles in the vicinity of aerodromes (e.g. in the USA), but no guidance is provided on how to assess obstacles which actually do penetrate relevant limitation surfaces.

This leads to a lot of confusion and conflict worldwide between project developers and aerodromes or aviation authorities, notably as aeronautical studies can get very complex if mitigating measures have to be implemented.

The Korea Transport Institute (KOTI), an innovative “think tank” supporting the local ministry of transport, identified this deficit in Korea and commissioned airsight to develop a proposition for the applicable aeronautical study requirements for assessing obstacles in Korea.

airsight, as one of the world’s leading aviation safety consultancy and certified flight procedure organisation, has a considerable amount of experience in aeronautical studies. With more than 100 international projects on this subject, airsight has a great knowledge of the world’s best-practices, methodologies – and most importantly the pitfalls to avoid.

This assignment was embraced by airsight consultants with great enthusiasm, as an opportunity to review international regulations, identify which works best, and derive guidelines for the future Korean regulations on the subject matter that are safe, fair, simple and efficient.

Within a few months, the airsight team considered numerous aspects in their analysis, including for instance: the triggers of an aeronautical study and its process, the responsibility of the different stakeholders, the applicable requirements on entities conducting aeronautical studies and the elements that shall be contained in an aeronautical study – notably the impact and risk assessment methodology, the acceptable mitigating measures as well as the approval process. KOTI’s initiative will hopefully improve the relationship between aviation and non-aviation stakeholders in Korea, and serve as a model for other countries facing similar challenges.