ECSS-Q-40-04A Part 1 – Sneak analysis – Part 1 Method and procedure (14 October 1997)

This document has been superseded by ECSS-Q-TM-40-04 Part 1A (16April2010).


The aim of Sneak Analysis is to identify “sneak circuits”, i.e. unexpected paths for a flow of mass, energy, data or logical sequence that under certain conditions can initiate an undesired function or inhibit a desired function. Sneak circuits are not the result of failure, but are latent conditions, inadvertently designed into the system.

This standard establishes a procedure for performing sneak analysis and specifies the required output.

The standard is composed of two parts:

  • part 1 (i.e. this document ECSS-Q-40–04 Part 1 “Sneak analysis – Part 1: Method and procedure”) that contains the method and procedure for performing sneak analysis;
  • part 2 (i.e. the document ECSS-Q-40–04 Part 2 “Sneak analysis – Part 2: Clue lists”) that contains a basic clue list to be used during sneak analysis.

This standard is applicable when the performance of sneak analysis is required by ECSS-Q-40 or by the contract between the customer and the supplier.

Alternative sneak analysis procedures proposed by the supplier may be accepted by the customer provided that equivalence, for the intended application, with the one presented in this standard is shown by the supplier.

This document was re-confirmed by the ECSS Technical Authority on 7 December 2022 (TA80).