What is being referred to here is English for Specific Purposes (ESP) and I would think that any competent teacher could adapt, given further study. As an example of ESP, I was offered a job teaching airline English, to an international agreed standard, to Chinese domestic pilots. A former boss was offering a very good package, but the timing was wrong and would have required a return home, several months of waiting until the contracts with the airlines were signed, and a new visa. But I have never flown a plane or worked at an airport! I did however recommend a course book and (audio material) written by a former pilot, and published at the same time as the job offer.I also looked at the research for air crashes and found that a percentage of crashes were down to pilot and ground crew mis -communication in English. "Descend to 22,000 feet" was heard by the pilot as "...2,000 feet" and ended in disaster. My purpose in doing the research was a PP presentation to the airline companies.

There are posts on other ESL sites from teachers who have already worked in this field. And Macmillan in the UK have published "Campaign" :-

"Campaign is a three-level English language course English for the military designed for multinational military and peacekeeping forces on peacekeeping operations.

All three levels of this award-winning Military English course are now available. Providing approximately 200 hours of teaching materials and consisting of four components, this flexible course syllabus can be adapted for any length of course. If you are teaching English find out more about Campaign - English for the Military."

http://www.campaignmilitaryenglish.com/

Turnoi has provided an example of what could be meant by the phrase from the article that you highlighted. The vocabulary, and understanding the context may be different, but it's amazing what good teachers can teach given the opportunity.

But the screening and checking process for applicants will, I expect be very thorough indeed.