Systematic root cause analysis for safety-critical systems.
Similar to FMEA and HAZOP analysis, Fault Tree Analysis (FTA) is a method of systematic risk analysis.
Originally developed in aviation, it has established itself primarily in areas where the safety of technical systems has top priority.
Aim and special features of the fault tree analysis
The FTA makes it possible to describe not only individual fault events, but also complex faults that only arise through the interaction of several causes. This makes the method particularly suitable for safety-critical applications, for example in aviation, the defense sector or the automotive industry.
Procedure and methodology
The analysis begins with the definition of the so-called top event – the central failure event or a dangerous scenario (e.g. unmotivated acceleration in the vehicle).
The technical system is then broken down step by step – usually functionally – until only basic events remain at the end of the fault tree.
These basic events include, for example:
- Physical errors
- Specification error
- Operating errors or tampering by the product user
Since the fault tree analysis is based on Boolean algebra, probabilities for the occurrence of the top event can be calculated as soon as occurrence probabilities (e.g. in the form of failure rates) are assigned to the base events.
Anforderungen an die FTA
Eine wesentliche Voraussetzung für korrekte Ergebnisse ist das Vorliegen einer Funktions- und Fehlfunktionsspezifikation des zu analysierenden Systems. Fehlt diese Grundlage, muss sie zunächst erarbeitet werden – andernfalls drohen falsche Modellierungen und fehlerhafte Berechnungen. Ein typisches Risiko in der Praxis sind nicht erkannte Common-Cause-Fehlerursachen, die zu erheblichen Fehlinterpretationen führen können.
Our services
- Preparation and development of functional and malfunction specifications
- Creation and moderation of fault trees for technical systems
- Calculation of failure probabilities and system failure rates
In combination with other methods
Fault Tree Analysis (FTA) is often used together with FMEA / FMECA and HAZOP analysis.
While FMEA assesses individual component risks, FTA identifies system-wide dependencies – both methods complement each other ideally in reliability and safety assessment.
