Structured Authoring
ASD-STE100 — The Simplified Technical English Specification
Overview
What is ASD-STE100?
ASD-STE100, Simplified Technical English, is the international specification for writing technical documentation in a controlled form of English. It has two parts: a set of writing rules governing grammar, style, and sentence construction, and a controlled dictionary of approved general words in which each word carries exactly one meaning. The result is content that a global maintenance workforce — much of it reading English as a second language — can act on without ambiguity, and that costs measurably less to translate. The specification is maintained by the ASD Simplified Technical English Maintenance Group; the current issue is Issue 9, published in January 2025.
Key Features
- Part 1: writing rules for grammar, style, and sentence construction
- Part 2: a controlled dictionary — one approved word, one meaning
- Technical names and technical verbs admitted under defined rules
- Maintained by the ASD STEMG; current issue is Issue 9 (2025)
- Commonly specified alongside S1000D and ATA iSpec 2200 deliverables
Also written as: Simplified Technical English · STE · STE-100 · ASD STE100 · AECMA Simplified English
Who ASD-STE100 Applies To
ASD-STE100 applies the way most documentation standards do — a contract or a program's writing standard cites it — but its reach is wider than its citations: it grew out of civil aviation maintenance documentation and is now specified or recommended across aerospace and defense programs, commonly alongside S1000D and ATA iSpec 2200 deliverables. It governs the sentences, not the structure — which is why it combines with any content architecture rather than competing with one.
Where ASD-STE100 Programs Go Wrong
- Buying a checker before training the writers. STE is a writing capability; tooling verifies it but cannot supply it, and a team armed with a checker and no training produces compliant-scoring text that still reads badly.
- Reading the dictionary as a ban on technical vocabulary. The controlled dictionary covers general words; technical names and technical verbs are admitted under the specification's own rules, and most 'STE won't let us say it' objections dissolve there.
- Retrofitting STE mid-program without pricing re-verification. Rewriting existing content into STE changes approved text, and in regulated documentation changed text has to be reviewed again — plan the conversion with that cost on the table.
How It Relates to Other Standards
- S1000D
- The pairing people mean when they say "S1000D and STE": data modules structured by one specification, written in the language the other defines.
- ATA iSpec 2200
- The world STE grew up in — controlled language for commercial aircraft maintenance documentation predates the current specification by decades.
- DITA
- Orthogonal, not alternative. The architecture governs structure and reuse; STE governs the prose inside it. Enterprises adopt both for the same reason: consistency at scale.
ASD-STE100 Questions
What is Simplified Technical English?
A controlled form of English for technical documentation, defined by ASD-STE100: writing rules that constrain grammar and sentence construction, plus a controlled dictionary in which each approved general word has exactly one meaning. The point is unambiguous instructions — for global workforces reading English as a second language, and for translation pipelines where every ambiguity is paid for in every target language.
What is the current issue of ASD-STE100?
Issue 9, published in January 2025, superseding Issue 8 of 2021. The specification is maintained by the ASD Simplified Technical English Maintenance Group and issued free of charge on request.
Is STE mandatory?
Only where a contract or program writing standard makes it so — but in aerospace maintenance documentation that is common enough to treat as the default expectation. Even unmandated, the economics tend to argue for it: controlled language cuts translation cost and reader error in exactly the content where errors are expensive.
Does STE forbid technical terms?
No — this is the most persistent misreading of the specification. The controlled dictionary constrains general vocabulary; technical names and technical verbs are explicitly admitted under defined rules. What STE removes is not your terminology but the ambiguity around it.
Where to Get ASD-STE100
The specification is issued free of charge by the ASD Simplified Technical English Maintenance Group — request a copy through the official STE site. The current issue is Issue 9, published in January 2025.
Where ASD-STE100 Applies
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