Yes, it does sound as though she may have a 'calling' of some sort!
In my case I was around the age of ten before I could identify the majority of helicopter types by sound.
Worse was the fact that I would bug my classmates with 'helicopter noises' every so often. The Allison C20B starting and Gazelle were my specialties. Oh the innocence of youth!
Here, the Army craft your daughter most likely saw and which (in these circles) is commonly referred to as a 212:
