Category Archives: Organization management

The thing Changed in the System Development Lifecycle of ISO 26262-4:2018

In first edition, Safety system requirement stage and safety system design stage are distinguished. I’ve thought that it was natural until 1 year ago. But Applying ISO 26262, it was vague.

My major question applying ISO26262-4:2011 was

Comparing Automotive SPICE and ISO 26262-4, TSR specification is performed in ENG.2(Requirement specification) phase? But the details of TSRs cannot be determined in the ENG.2 stage.

Because requirement and design is distinguished in the ISO 26262 standard, I’d like to define the two.

  • Requirement defines what shall be done.
  • Design define how shall be implemented.

Safety relevant functions are closely related not only to requirement, but also to design decision in the supplier aspect.

Safety mechanisms are belong to TSR, but they are design decision to handle failures that are related to safety.

When I realized the fact, I feel so confused. Then how deep should I recommend functional safety engineers to specify TSRs? How should I define development life-cycle? How to combine from existing development lifecycle?


My conclusion is that I don’t have to distinguish between safety requirement and safety design, because major contents specified in the Technical Safety Requirements stage are derived from design decision.

After Safety analysis results, TSRs are additionally identified and safe design decision is defined. Then, TSR stage does not just cover requirement stage.

So my idea is that TSR does not cover fully ENG.2(requirement specification) and ENG.3(design specification) both but is in the overlap of both ENG.2 and ENG.3. and TSC is in ENG.3

When I review latest ISO 26262-4:2018, I thought that the author of the standard might be in the similar situation. I do not know the real, anyway I welcome that TSR stage and Safety design stage are merged.


Resource reduction for functional safety projects

How can we reduce resource in the functional safety project?

It is easy to say that we develop perfectly and reuse without modification for the next project. But how?

  1. build platform to support functional safety project.

  2. build library asset for functional safety project.

These projects are not customer based project. But I believe they are most important.

in these projects, every work products have to be produced and they should be linked to individual customer project. To achieve them, additional project team has to be organized and it consists of best experts.

Power of your words

To be a functional safety manager, it is very important to have a power of words. As a functional safety manager, if my asking, which is a request somebody to do something, sounds like a dog’s barking, what will happen?

I remember a Sun Tzu’s history. Sun Tzu is an author of “The art of War”. He believed that usage of military strategy is effective compared to just “fighting”. It is natural, but at that time there was no such a concept of strategy.

At first his concept is not accepted when he was appointed as a war strategist. King said that if your word is true, show me using my several maid of honor.

They felt that it is a fun. But he is very serious. He felt hurt in his pride. So he commands but they did not follow.

He considered this situation is a violation of military rule, and its punishment is beheading of two heads of maid of honor.

The king was in panic, and they were also. King tried to hesitate him, but he killed both.

So, how will you change your environment? You cannot kill people, how can you make them change their perception? How can you cultivate culture of functional safety?


This story might help you how to start.