u/Business-Station-933

I was flying a C150 today when suddenly a loud, rapid TATATTATATATATATA (lol) sound started during cruise. It sounded almost like the starter motor grinding/chattering before the engine catches, but it sounded like it was coming from behind me (tail/fuselage area), not from the engine (again, could be wrong). It was audible enough to be alarming even with engine at crusing RPMs and headsets.

Some thoughs that crossed my mind (in order):

Wing is failing;
Engine is failing;
Elevator is failing;
Something hitting fuselage (maybe a part of the belt... but had to me metallic), and I was wearing full belt, so there is literally no way;
Aerial flicking and hitting the ceiling.

So:

It started in flight (around 30 minutes after reaching cruise altitude) and continued all the way until landing.
No change in engine sound or performance.
I checked if a seatbelt was hitting the fuselage (even opened and closed the door 2 times) — nothing.
No electrical issues noticed (no flickering lights, etc.);
It disappeared (or was less noticeable during climb).

I thought it might be an antenna (aerial) fluttering or flicking in the airflow, but I'm not sure.

I know it is a bit ...vague... but...as anyone experienced something similar in a 150/152? Common causes for this kind of noise?

Thanks in advance!

Ergonomic chair misaligned... fixable?

Weird metallic noise during cruise...any ideas? (Cessna 150)