An obstacle study must allow for the replication of the results for each object analyzed. Coordinates, elevations, airfield configuration, and the reference surface form a verifiable data chain. OLS geometric analysis and the assessment of effects on CNS involve different objects.
What should the object inventory contain?
Identify each structure, installation, tree, or temporary obstacle using a unique code. For volumetric objects, collect the characteristic points of the contour and the elevated elements, not just the center of the footprint. A long building may intersect surfaces at different elevations.
Record the nature of the object, coordinates, ground elevation, height, and peak elevation. For vegetation, note the date of observation; for cranes, describe the position, working envelope, configurations, and period. Photographs help with identification but do not replace measurements.
How do you verify coordinates and altitudes?
Data must specify the planimetric system, vertical datum, units, and available precision. An ellipsoidal altitude and an elevation relative to a vertical system cannot be compared directly. Transformations must be documented, and verification should use appropriate benchmarks and control points.
Keep the source files, measurement report, date, and the responsible person. In the aeronautical data catalog, every value must be traceable to its origin and the verifications performed. Corrections must receive a revision number, without uncontrolled overwriting of history.
How is the comparison with OLS and OFZ constructed?
The calculation configuration starts from thresholds, axes, elevations, and operation types. The applicable surfaces are identified, and the position of the objects relative to these is verified. The report shows the surface elevation at the analyzed point and the difference from the object's elevation, with an explicit sign convention.
RACR-ZSAC and CS-ADR-DSN are selected according to the object of the assessment. OLS, OFZ, and flight procedure protection are not interchangeable terms. If instrument procedures are affected, the scope must be coordinated with the responsible specialists.
What does shadowing and ILS effect verification mean?
The existence of a taller obstacle in the vicinity does not automatically justify a new object. A shadowing principle analysis specifies the surface, the reference obstacle, its stability, and the geometry of the justification, within the limits of the criteria accepted for the situation analyzed.
For ILS/CNS, reflection, diffraction, materials, and surface orientation are also relevant. Electromagnetic shadowing does not result from an OLS cross-section. When an assessment according to a DANA procedure is requested, the applicable version and the necessary data set must be established with the authority; do not assume criteria from unavailable internal documents.
What results and information should you request in a proposal?
Request the verified inventory, plans and cross-sections, calculation base, results per object, and list of limitations. Data for the catalog and publication must be delivered in agreed-upon formats, along with metadata.
Send the site location, purpose of the study, airfield configuration, and available measurements. Specify whether temporary obstacles, CNS, shadowing, or catalog updates are included, so that the analysis covers the technical question precisely.
Consult the technical chapter in our guide
Discuss your project with the Sky Meridian team
Obstacle studies and aeronautical data