In this sentence, "After takeoff, aircraft A was instructed to turn to heading 070°", is 070° used as an adverb modifying "heading"?
No, it's a noun.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
a heading of 70°
a 70° heading
heading 070°
All are ok combinations. Pilots use a standard international language.
Heading is a noun.
70° is a noun.
Nouns commonly modify other nouns.
A rose garden
A doll house.
A brick wall
A stone path
A fire hose
A Disney character
etc.
fire1heading 070°
Some grammars say that numbers form their own lexical category; others say they're nouns; others say determiners/determinatives.
Because of the "degree sign" you're talking about seventy degrees, so you may as well say that 70 is a determiner.
In any case, whatever you call the number, it's the same in all other expressions lik