Aircraft Reliability

[shekar_RS]

1) When we are specifying the reliability goal for the aircraft, what is the specific mission duration to be specified along with the reliability goal.

2) Should aircraft reliability goal be used as a design intent or operational requirement?

3) How to ensure the aircraft reliability say 95% before each mission even after logging say 500 flight hours?

[gkrasin]

I think this depends on the specific task. The shortest mission duration is the duration of flight. But mission duration could depend on maintenance requirements because different systems and components are replaced, repaired, or inspected at different intervals.

Aircraft system design and analysis requirements and acceptable means of compliance are given by EC CS 25.1309 / AMC 25.1309 (http://www.easa.eu.int/ws_prod/g/doc/Agency_Mesures/Certification_Spec/CS-25%20Amendment%206.pdf) or FAA FAR 25.1309 / AC 25.1309 (http://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/22680)

[Norbyzuka]

In france, we use ABD100 1.3 E (airbus) for the reliability studies.

FIDES (UTE-C 80-811) is used for the electronic components.

The MTBF is in flight hours with a complex mission profile (like 217plus).

We use a mission time (like 2 hours) for Fault tree analysis (probability of failure in AIC environment for a mission of 2 hours)

In complement, we use ARP4754 (design), ARP4761 (Safety analysis), D0254 (compex components), D0178B (software).

Boeing use also this standards ? (ARP..., DO...)