Hello,

Actually there is no any special exam for joining technical ground duty in air force. Change of Branch is not allowed normally but in exceptional  become a Technical officer you should have an Engineering Degree It is up to Air Head Quarters to approve.Instead of joining as an Admin Officer and then trying to become a Technical Officer,you can apply for Technical Officer, if you have an Engineering Degree. And you are btech from EC then it is possible to apply for technical one .