The short version

• Use the tool freely for personal, educational, and professional reference. It is not certified for operational flight planning.
• The site, its source code, its performance, fuel, emissions, wind, range and ETOPS models and calculations, its compiled data, and its design are proprietary to Great Circle Pro.
• Do not copy, scrape, bulk-download, reverse-engineer, resell, or build a competing product from any part of the tool, its outputs, or its data.
• The figures are good-faith estimates provided "as is," with no warranty. Do not rely on them for real-world dispatch or safety-of-flight decisions.

1. Acceptance

By accessing or using Great Circle Pro (the "Service"), you agree to these Terms of Use. If you do not agree, do not use the Service.

2. License to use

Great Circle Pro grants you a limited, non-exclusive, non-transferable, revocable license to access and use the Service for your own personal, educational, or professional reference. This license transfers no ownership and does not permit any use described under Prohibited uses below.

3. Intellectual property

All content and technology that make up the Service are owned by Great Circle Pro and protected by copyright and other intellectual-property laws. This includes, without limitation:

• the source code, scripts, and software that run the tool;
• the performance, fuel, emissions, wind, range, and ETOPS models, methods, coefficients, and calibrations;
• the compiled aircraft, airport, and route datasets and their selection and arrangement;
• the text, blog articles, diagrams, branding, and visual design.

The Service runs in your browser, so its files are necessarily delivered to your browser in order to function. That delivery does not place any of it in the public domain or grant you any right to copy, store, or reuse it. All rights are reserved.

4. Prohibited uses

You may not, directly or through any automated means, and whether or not for commercial purposes:

• copy, reproduce, republish, mirror, or redistribute the Service, its code, or its content;
• scrape, harvest, or bulk-extract the data, calculations, or outputs of the Service;
• reverse-engineer, decompile, or attempt to reconstruct the underlying models, coefficients, or methods;
• use the Service, its outputs, or its data to build, train, or operate a competing product or dataset;
• resell, sublicense, or commercially exploit any part of the Service without our written permission;
• remove or obscure any copyright, trademark, or proprietary notice.

5. No warranty; not for operational use

The Service is provided "as is" and "as available," for educational and planning-reference purposes only. It is not certified or approved for operational flight planning, dispatch, navigation, or any safety-of-flight decision. All ranges, flight times, fuel figures, emissions, and ETOPS results are good-faith estimates derived from published data and modeling, and may differ from real-world performance. We make no warranties of any kind, express or implied, including accuracy, fitness for a particular purpose, or non-infringement.

6. Limitation of liability

To the fullest extent permitted by law, Great Circle Pro shall not be liable for any direct, indirect, incidental, consequential, or special damages arising from your use of, or inability to use, the Service or its outputs. You use the Service, and any figure it produces, at your own risk.

7. Accounts

Some features require a magic-link sign-in. You are responsible for the security of the email account you use to sign in. We may suspend or end access that violates these terms.

8. Changes to these terms

We may update these terms from time to time. Material changes will be noted on this page, and continued use of the Service after a change means you accept the updated terms.

9. Contact

Questions about these terms, or requests for permission to use our content: use the contact form.