It is wrong because the section of the Manual of Style on section headings explicitly says (in the last bullet point):
"If there are no blank lines above the heading, one line should be added, for readability in the edit window." [emphasis mine]
Your continual removal of this blank line appears to be based on a misinterpretation of the Headings and sections section of the Manual of Style page on Layout, which states:
"Between sections, there should be only a single blank line; multiple blank lines in the edit window create too much white space in the article."
It is obvious from both the previous quotation and last sentence of this one that the instruction "there should only be a single blank line" is referring to the layout in the edit window and not that of the finally rendered page.
It is not at all obvious to me that the aircraft specification template is broken. The bug which produces the extra newline could well be in the rendering software rather than the template itself. But in any case, since your removal of the single blank line in the edit window is contrary to the style guidelines, I shall revert it.  Please do not revert again without giving a more substantial reason than you have so far offered for doing so.  Also, since you are apparently editing from a dynamic IP you may not have seen my note on the 3-revert rule on the talk page of User 91.55.206.73.  If not, please do so.
— (talk · cont)