Making the world better, one answer at a time. its not a case of how many grades you need, its more based on what grades you have. to begin a pilot training course you need at least a C in science physics, chemistry, B/C in maths and decent knowledge in geography and it can be very handy to have a second language.ou can gain ratings with either a CPL or PPL. A Instrument Rating is the primary rating that you need to add to your qualifications to become an airline pilot. This allows you to fly in cloud and navigate with reference to the aircraft instruments. Some airlines operate aircraft powered by gas turbines.