Hello,

Hope you are doing good.

Well, it's very good that you are pursuing Aircraft maintenance engineering.
UPSE examination only require you to be a Graduate in any stream.
You can opt for the optional paper  related to your subject of graduation.

Good luck!!
Hope this helped.

Yes, criteria for UPSC is only Graduate in any stream. Consistency and Dedication and Perfection are the important keys in UPSC preparation.

Hope you will get right path.

Best of Luck.

Have a Bright Future.