Hello Ashok,

Firstly, AFCAT is conducted for candidates who are either graduates or are pursuing their final year of graduation. So you will be eligible to appear for AFCAT once you are done with your graduation or in the final year.

The basic requirement for AFCAT is that you should score atleast 60 marks in Physics and Mathematics individually at the intermediate level if you wish to be pilot in the Indian Air Force. If you wish to appear for Ground Duty then there is no such requiremnt at the intermediate level. Another requirement for AFCAT is that you should have minimum 60% aggregate at the graduation level irrespective of the stream. 

Answering your question, YES you can definitley clear AFCAT without studying a non medical subject or for that matter are ELIGIBLE to appear for the same after your graduation or in the final year.

Hope this answers your question well.

Thank you!