Your other posts are a bit confusing as you're talking about using Sigil and Calibre, but you're not saying where any of the examples you're pasting in came from. - i.e. 'exactly' how you got that text and pasted it into these forums.
If this line:
<h2 id="filepos167405"><span class="bold">Chapter 1 <a id="filepos167422"/>Flight Crew Duties and Responsibilities</span></h2>
Was created by/seen using Calibre, then the default chapter detection xpath will work - you shouldn't have to make any changes from defaults. However if you did that using Sigil then you need to finish what you started and do that for all the chapters.
You're not going to be able to easily avoid the sub-chapters - are you saying that you're successfully getting a TOC from Calibre but it's the sub-chapters you don't want?