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Terrain and Obstacle Data – The Challenge


Significant changes have been introduced with regards to the publication of terrain and obstacle data for aviation use. These changes require a shift from the traditional publication responsibilities of the State Aeronautical Information Services, to the provision of digital data, of a wider scope, requiring the engagement of a multi-disciplinary audience.

It has been a requirement for States to publish obstacle data within their Aeronautical Information Publication for many years. However, this information was provided in a simple, textual form, and limited in scope. Information relating to terrain has only been required in a very limited form and provided for runways for which CAT II/III operations are permitted, by way of the Precision Approach Terrain Chart, specified by ICAO Annex 4.

Whilst this provided sufficient information for the navigation techniques in use when the requirements were first developed, the advent of modern technology, improved navigation techniques and more sophisticated tools has led to a demand for digital data covering a more extensive area. The provision of such data will allow a number of advances in technology and the operating environment, leading to a desire for States to make available more extensive data sets which provide information relating to both terrain and obstacles.

The requirements for such data sets were introduced by ICAO in Annex 15, and became effective in July 2004. The introduction of these requirements resulted in considerable debate within the AIM community, much of which related to the affordability of the task and the apparent lack of a business case to justify the significant costs associated with implementation. The requirements also brought about a need for new competencies, such as knowledge of the ISO 19100 series of standards. Much work has been undertaken, primarily in Europe, to support the refinement of the ICAO requirements to offer significant cost savings over the original requirements introduced. This work resulted in Amendment 36 to ICAO Annex 15.

The applicable dates for the terrain and obstacle data Areas are as follows:

Despite the refinement of the requirements, significant work is needed in order to achieve compliance. In particular, the provision of data for Area 2 is widely considered to be the most challenging and complex to implement. A wide range of both technical and institutional issues have arisen and it is clear that careful planning and allocation of responsibilities is needed within a State in order to implement the requirements in an efficient and cost-effective manner.

Mileridge courses will help you to understand and appreciate the challenges of working with Terrain and Obstacle Data, and provide practical guidance on implementing the requirements of ICAO Annex 15. Find out more here.