Simplified Technical English (STE) is an international standard for creating maintenance documentation using a controlled language. Developed by the Aerospace, Security and Defence Industries Association of Europe (ASD), STE was introduced in the early 1980s to assist non-native English speakers in understanding technical manuals clearly. Initially focused on civil aircraft maintenance, it has since found use in various other industries.
Ambiguity in technical documentation can lead to confusion. Therefore, each instruction needs to be crystal clear. STE comprises a set of Writing Rules and a Dictionary of controlled vocabulary.
The Writing Rules categorize topics into procedural and descriptive writing. They also address grammar and style. Here are some key rules: use only approved words as defined in the dictionary; make instructions clear and specific; avoid passive voice in procedures; prefer active voice in descriptive texts; keep sentences short—no more than 20 words in instructions and 25 words in descriptions; do not omit any parts of sentences; use vertical lists for complex information; write one instruction per sentence; limit paragraphs to one topic with no more than six sentences; and start safety instructions with a clear command.
The Dictionary contains enough words to express any technical sentence simply and effectively. Words were selected for their clarity and ease of recognition. When synonyms exist, this specification chooses one to ensure consistency, following the principle of ‘one word – one meaning.’ For example, ‘start’ is preferred over ‘begin,’ ‘commence,’ or ‘initiate.’ Additionally, when a word has multiple definitions, the specification selects one definition to avoid confusion. For instance, ‘to fall’ means ‘to move down by the force of gravity’ rather than ‘to decrease.’
