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Fault Tree Analyser

FTA Basics

Fault Tree Analysis is one of the most widely used methods in system reliability and failure probability analysis. A fault tree is a graphical representation of a logical structure depicting undesired events ("failures") and their causes. You create the logical structure by using gates and represent undesired incidents by using basic events. Reliability parameters are assigned to each basic event. Widely used in system reliability studies, fault tree analysis offers the ability to focus on an event of importance, such as a highly critical safety issue, and work to minimize its occurrence or consequence. The probability of a top-level event can then be determined by applying appropriate mathematical techniques. The resulting fault tree diagram is a graphical representation of the chain of events in your system or process, built using events and logical gate configurations.

Fault Tree Analyser by ALD

The fault tree analysis tool is provided for free. You may create fault tree, calculate probability, get the reports and save the fault tree to your own PC for future use.

There are no limitations in the functionality of the tool or size of the fault trees you may build. You may download and upload fault trees you build to and from your own PC.

You may start using the tool right now, from your tablet or PC, using any operating system, without a need to download or install the tool – it is web based!

Build your fault tree

You may build fault tree with OR, AND, K-out-of-N (voting) gates and different types of basic events, including Evident, Latent, External, Repairable and Unrepairable.

Building a Fault Tree


Calculate your fault tree

Calculate your fault tree probability/unavailability (including events and intermediary gate probabilities) for Mission time (with defined mission duration) or for Steady-state mode.

Calculating a Fault Tree

Get your fault tree reports

Generate and download reports for your fault tree – list of Minimal Cut Sets, list of fault tree events and gates.

Fault Tree Reports

Save your fault tree

When you finish building your fault tree, download it to your own PC. Upload it back to our Fault Tree Analysis tool when you need to work with this fault tree again. You may download, store and upload unlimited number of fault trees on your PC. This way, you are in charge for your information, it is not stored on our servers, no risk to loose condifential information.

Saving a Fault Tree

Software As Free Service

The Free Web Fault Tree Analyser is provided in "Software as free service" mode. It is installed on and powered by our infrastructure and IT, is available worldwide and free. You do not need to install anything. All what you need to have in order to use it is a compatible web browser and FT analysis basics knowledge.