ASD-STE100 Simplified Technical English (STE)

Write, rewrite, and verify technical text against ASD-STE100 Issue 9 (January 2025). STE is a controlled natural language owned by ASD (Aerospace, Security and Defence Industries Association of Europe). It makes technical text unambiguous, easy to understand, and easy to translate. The standard has two parts: 53 writing rules in 9 sections (Part 1) and a controlled dictionary of about 900 approved words (Part 2).

STE is not simplified English for learners. It is a precise standard that requires strong English proficiency to apply. It adds to, but does not replace, a style guide.

When to Apply This Skill

• Rewrite existing technical text (manuals, procedures, warnings) into STE
• Write new STE-compliant procedures or descriptions
• Review text for STE compliance and report violations
• Explain STE rules, the dictionary, or the standard

Rule 0: Meaning Outranks Vocabulary

Before any other step: never change a technical fact, drop a qualifier, delete an object, or invent an agent in order to satisfy the dictionary. STE removes ambiguity; it does not remove content. A sentence built entirely from approved words that states something false or empty is a worse failure than a sentence that keeps one flagged word.

This is the failure mode that makes an STE rewrite look compliant and read plausibly while being wrong. Three signatures to watch for in your own output: