In this example, "deactivate" is not approved. The Dictionary suggests the alternatives DISCONNECT, STOP, and ISOLATE. In some contexts, these alternatives would be satisfactory. However, in this example:
 
      DISCONNECT would be technically incorrect.
 
      STOP and ISOLATE would be meaningless.
 
 You must ask yourself:
 
      "What does 'deactivate' really mean in this context?", or
 
      "What must the operator do specifically?"
 
 You will then realize that the deactivation is the result of a specific action: locking the air inlet valve in the fully open position. So, if you tell the operator to do just that, your instruction will be meaningful. The operator will do the correct action without wasting time or wondering what you really meant. And the operator will get the desired result.
 
 In the previous examples, we have seen how you can write around a single unapproved word in a sentence, and how you can reformulate a sentence. But frequently, there will be more than just one unapproved word or construction that you want to write around. And to reformulate an idea, you will not always be able to limit the changes to a single sentence. You will also have to change other text.
 
 Example:
 
 Instead of:  If cracks are detected during this procedure, the operator must perform the repair within a certain number of flight hours depending on crack length. See table below.

 
 Crack length detected  Time before repair (flight hours)
 L>  1000
 L=...  2000
 L<...  3000

 
 WRITE:  If you find cracks, refer to the table that follows:

 
 If the crack is this length  Do the repair before (flight hours)
 L>  1000
 L=...  2000
 L<...  3000

 
 In this example:
 
a.    The words that are underlined are not approved in SE (refer to Rule 1.1).