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Declared Distances in Minutes: LDA, TORA, ASDA, and TODA with AOI Web Pro

AOIWEB LTD · 14 March 2026

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If you plan or assess runways, you know how often declared distances need to be recalculated: design changes, new obstacles, different aircraft, or updated regulations. Doing it by hand is slow and error-prone. A tool that computes LDA, TORA, ASDA, and TODA and shows the result visually can save time and reduce mistakes.

Why declared distances matter

Declared distances define what pilots and operators can use for take-off and landing:

  • LDA (Landing Distance Available) – length available for landing.

  • TORA (Take-Off Run Available) – length available for the take-off run.

  • ASDA (Accelerate-Stop Distance Available) – length available for accelerate-stop.

  • TODA (Take-Off Distance Available) – length available for take-off distance (run + clearway).

Getting these right is essential for runway safety and capacity. Errors can affect runway classification, aircraft eligibility, and operational limits.

Calculating and visualizing in one place

In AOI Web Pro, the declared distance calculator lets you:

  • Work with existing runways from your project or define custom runways.

  • Enter or adjust the main inputs (runway dimensions, clearway, stopway, displaced thresholds, etc.).

  • Get LDA, TORA, ASDA, and TODA computed in real time.

  • See a real-time graphical view of the runway and declared lengths, so you can check that the numbers match the geometry.

As you change inputs, the numbers and the diagram update together, which makes it easier to spot inconsistencies and explain results to colleagues or regulators.

Built for airport planning and safeguarding

The calculator fits into the rest of AOI Web Pro’s workflow: obstacle limitation surfaces, aerodrome safeguarding, and airport planning. Declared distances stay consistent with your runway data, so you can move from design to documentation without re-entering everything in a separate spreadsheet.

Whether you’re updating an existing runway or evaluating a new layout, having LDA, TORA, ASDA, and TODA, and a clear picture of how they’re derived, helps keep operations safe and compliant. If you’d like to see it in action, the short demo video on our LinkedIn feed shows the calculator and the live graphical view in use.