How should I understand 'necessary' in this sentence?

[Liqichao]

The object of the aeronautical information service is to ensure the flow of information necessary for the safety.

I am confused about the meaning of 'necessary'. thank you for your answers

[Diverhank]

"Necessary" in this case almost means "required". You can almost rewrite this as "...ensure the flow of required safety information". Hope this is clearer. By the way, what kind of business do you do? I can tell it's aviation related.

[Liqichao]

I am an English training teacher for air traffic controllors, thus I have to learn a lot of aviation english. hehe...

[Diverhank]

So is part of your job to translate English to Chinese and vice versa? This sentence sounds like it comes from some FAA document except for the last part. The ending "...necessary for the safety." seems to be missing something. After reading it, I'd ask "for the safety of what"? I'd either lose the "the" or to expand, for example: "...information (that is) necessary for safety." or "...information (that is) necessary for the safety of the pilots"

[Liqichao]

yes, I definitely omit the ending: for the safety, regularity and efficiency of international air navigation.

I am not an interpretor but a teacher. The chinese air traffic controllors have very limited English skills to deal with an emergency or unpredictable situation except some routine proficient aiviaton English, and that's why I am there to help them.

[Diverhank]

I've been an aerospace engineer for almost 30 years. I'm very familiar with aviation terminology. Perhaps I can help you with some of the aviation terms .

[Liqichao]

Thank you so much. My dear Sire.