there are several different types of ratings for flight instruction. These instructor rating can be issued for different categories of aircraft: Airplane, Helicopter, Balloon or Sailplane, e.g. a helicopter flight instructor holds a FI(H). This section only covers the aeroplane instructor ratings. Flight Instructor (FI) teaches basic flight instruction towards a license (PPL or LAPL), and may instruct in 'difference training' for different types of add-on endorsements, e.g. tail wheel or retractable gear. A FI may also hold the privileges from any other instructor rating such as IRI or CRI, as well as other instructor privileges such as CPL, Night or Aerobatics. Instrument Rating Instructor (IRI) teaches instrument flying towards an instrument rating under a modular program. Class Rating Instructor (CRI) instructs on a certain class of aircraft towards a class rating for those who already hold a license. Class ratings may include Single Engine Piston Land (SEPL), Multi Engine Piston Land (MEPL), Single or Multi Engine Piston Sea, or Single Engine Turboprop under a modular program. Canada This section currently covers only the aeroplane flight instructor ratings. In Canada, the holder of a commercial pilot licence or airline transport pilot licence may have their licence endorsed with a flight instructor rating - aeroplane. Initially, the pilot is endorsed as a "Class 4" flight instructor. This allows the pilot to deliver flight training towards the issuance of a recreational pilot permit, private pilot licence, commercial pilot licence, night rating, and VFR over-the-top rating. The "Class 4" flight instructor may only conduct training while under the supervision of a "Class 2" or "Class 1" flight instructor. After satisfying certain requirements (satisfactory flight test records, experience requirements, written exams, and flight tests), an instructor can upgrade their rating to a Class 3, Class 2, and Class 1 instructor rating. The Class 3 flight instructor does not require the supervision of a Class 2 or Class 1 flight instructor. The Class 2 flight instructor may supervise Class 4 flight instructors and act as the chief flight instructor (CFI) of a flight training unit. The Class 1 flight instructor may give ground school and flight training towards the endorsement of a flight instructor rating. In order to give instruction towards the instrument rating, multi rating, type ratings, and class conversions (for example, land plane to sea plane), an instructor rating is not necessarily required. The requirements may be limited to holding a commercial or