ste100
ASD-STE100 (non-slop writing)
What the standard is
ASD-STE100 Simplified Technical English (STE) is a controlled form of English. The European aerospace industry (AECMA, now ASD) started it in 1983 for aircraft maintenance manuals, and the first guide came out in the mid-1980s. The current version is Issue 9, released January 2025. It is the first issue published as an international standard. The ASD Simplified Technical English Maintenance Group (STEMG) maintains it, and ASD gives it out free of charge on request through asd-ste100.org (free since Issue 6, 2013).
The standard has two parts:
- Writing rules (53 in recent issues) in nine sections: words, noun clusters, verbs, sentences, procedures, descriptive writing, safety instructions, punctuation and word counts, and writing practices.
- A dictionary of about 900 approved words. Each approved word has one meaning and one part of speech. The dictionary also lists common unapproved words with approved alternatives. Technical names and technical verbs for your field (for example "API", "commit", "deploy") are allowed by the writing rules even though they are not in the dictionary.
Be honest about compliance. You do not have the official dictionary. This skill gives text that follows the countable rules. It does not make text "STE compliant". Never claim compliance. For regulated documents (aviation, defense, medical devices), tell the user to check the output against the official standard with a trained STE writer.
The core rule: change the words, never the substance
Simplify how the text says something. Do not drop facts, numbers, identifiers, commands, caveats, reasons, or recommendations. Keep the original strength of every claim: "usually" stays "usually", "must" stays "must". If a point needs 6 short sentences, write 6. Add nothing that is not in the source. If a rule makes the text wrong or vague, break the rule.