They are two fundamentally different skills. The simple solution is to have the writer critique the engineer's document. The common excuse here is, "The writer does not understand the system." However, this is exactly the reason the writer should review the document. The writer is concerned about the quality of the writing, and the content will not distract the writer like it would an engineer.
The document in front of me has a paragraph with one, 35 word sentence. The paragraph should be two, 10 word sentences. The run-on, 35 word, sentence is an example of an unorganized thought. My guess is, the author decided, more words in less time would make her look good. We have all fallen into this trap, starting in elementary school. The author knows what she means, and has 35 words to prove it. I ask managers, and engineers, to take the time and let everyone understand your document, not just the authors.