Documentation

Everything you need to start checking obstacle compliance.

Getting Started

  1. 1

    Create a project

    Sign up or log in, then create a new project from the workspace dashboard. Give it a name that corresponds to the development site or permit application you're assessing.

  2. 2

    Select an airport

    Search by ICAO code or name and add the airport(s) whose surfaces you need to check against. OLS will generate the full set of OFS and OES surfaces based on the runway data.

  3. 3

    Run a point check

    Enter the latitude, longitude, and elevation (metres AMSL) of the structure you're assessing. Click Check Point to receive an instant pass/fail result for each surface.

Key Concepts

OFS — Obstacle Free Surface

A set of protected airspace volumes around a runway that must remain clear of all fixed and mobile obstacles to ensure safe aircraft operations. Defined in ICAO Annex 14, Volume I, Section 4.

OES — Obstacle Evaluation Surface

Surfaces used to evaluate objects that may affect instrument approach and departure procedures. Penetrating an OES requires a full obstacle assessment and may necessitate changes to approach minima.

ADG — Aerodrome Design Group

A classification (I through VI) based on aircraft wingspan and outer main gear width. The ADG determines the horizontal and vertical extent of obstacle limitation surfaces for a given runway.

Coordinate System

All coordinates use WGS 84 (EPSG:4326). Elevations are in metres above mean sea level (AMSL). The engine uses spherical-earth geometry for surface polygon generation.

Frequently Asked Questions

How accurate are the surface polygons?
OLS uses spherical-earth geometry derived from published ICAO Annex 14 dimensions. The accuracy is sufficient for planning and preliminary assessment purposes. For final design or published procedure changes, verify with a certified aeronautical study.
Which airports are supported?
OLS includes runway threshold data for thousands of airports worldwide. Search by ICAO 4-letter code (e.g. EGLL, KLAX, OPKC). If your airport is missing, contact us and we can add it.
What does "penetrates" mean in the results?
If a point's elevation exceeds the surface height at that horizontal position, the point "penetrates" the surface — meaning the structure would infringe the protected airspace. This is a non-compliant result requiring further investigation.
What is the difference between Area Analysis and Point Check?
A Point Check assesses a single coordinate. Area Analysis lets you draw a polygon on the map and assesses every grid point within it, producing a heat map showing which parts of a site are compliant. Area Analysis requires a Pro subscription.
Can I use OLS for official submissions?
OLS generates PDF reports suitable for supporting planning applications and initial authority submissions. The regulatory report follows ICAO format. Always confirm requirements with the relevant civil aviation authority.
What are the free tier limits?
The free tier includes 50 point checks per calendar month. Checks reset on the 1st of each month. Area analysis, footprint analysis, and PDF reports require a Pro subscription.
How do I reset my check count?
Check counts reset automatically at the start of each calendar month. Your usage is visible in the workspace sidebar. Upgrading to Pro removes the monthly limit entirely.

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