What is the performance level to be reached?
Functional analysis: find the elements of the external environment (EME) and the induced constraints

The key to a successful functional analysis (FA) is to make the right choices, if possible, to enable a complete, time-limited study.

The need expressed by the customer can be broken down into several options. Not all of them are necessarily selected:

• for economic reasons;

• because current technology does not allow the function to be performed without failure;

• because development requires too many resources;

• because the study completion deadlines will not be met.

Under these conditions, the need expressed by the customer, and which allows you to achieve total user satisfaction, can have many variations.

You need to translate the user's dream (expressed need)...