If you have completed your 12th grade with Physics Chemistry and Mathematics (PCM) from a recognised board or hold a 3-year engineering diploma (or are eligible for B.Tech) you become eligible for AME B1.1 Stream admission. So the right time to apply is as soon as you finish 12th PCM (or diploma) if you meet the marks and age criteria. This way, you don't waste time and begin your aviation training early.
Admission to AME B1.1 is via the national level entrance exam AME CET. You should apply when the registration for AME CET is open (for example for AME CET 2026, applications start from 1st September 2025). Therefore, the ideal time is shortly after 12th/diploma results, when AME CET registration begins this ensures you join the next batch without delay.
Fresher start: Starting B1.1 soon after 12th helps you complete the 2-3-year training earlier and enter the aviation job market sooner.
Better chances: As long as you meet age medical fitness (good eyesight, no colour blindness) and academic criteria, applying right away avoids missing out due to age limit or seat shortages.
You should apply for the AME B1.1 Stream of Aircraft Maintenance Engineering immediately after passing 12th with PCM (or after your engineering diploma) as soon as the AME CET registration window opens. That is the most appropriate and timely moment to begin your AME journey.