What does هَل mean?
It is used to introduce a yes/no question. In itself it doesn't 'mean' anything.
You can press on the word and see the meaning
No it doesn't mean "is". It is a question particle. The word "is" isn't there in the Arabic sentence.
What will be the difference between this answer and - is engineer ghassan good -
That would be هل المهندس غسان جيد؟