The course duration of pilot ground school can vary depending on your background and the type of licence you are pursuing. Normally the duration of pilot training ranges from 18 months to 24 months for a Commercial Pilot Licence (CPL). This includes both ground school classes and flying hours. However if you already hold a Private Pilot Licence (PPL) the pilot study duration may be reduced. This is because you have already completed some of the basic subjects and flight training hours required for CPL.
The pilot duration of study in ground school covers subjects like Air Regulations Navigation Meteorology and Technical General. Since a PPL holder has knowledge of some of these topics the course duration for pilot ground school could be shorter, depending on DGCA credit policies and your chosen flight school.
For a student after 12th the pilot course duration after 12th usually takes 2 years. But with a PPL the duration to become a pilot can be reduced by several months. In general the duration of pilot training course for CPL is 200 flying hours in India and a PPL holder already completes a portion of this.
Its important to note that the pilot license duration depends not only on flying hours but also on weather exam schedules, and personal progress. The airline pilot course duration after CPL and type rating can add another 6–12 months.
In short while the pilot study course duration normally takes 18–24 months holding a PPL allows you to finish faster. So yes if you already have a PPL your duration for pilot course can be shortened helping you reach your dream of becoming a professional pilot sooner.