Applicability and terms used

This regulation introduces the training program requirements for Part 121 air carriers (airlines) and defines key terms used throughout the subpart.

It establishes that airlines must create and maintain training programs for crewmembers, dispatchers, and operations personnel, and covers how flight simulators and training devices may be used. The regulation also categorizes aircraft into two groups: Group I (propeller-driven, including piston and turboprop) and Group II (turbojet).

The definitions matter because they determine what training you need:

• Initial training: Required when you haven't previously qualified on any aircraft in that group
• Transition training: Moving between different aircraft within the same group
• Upgrade training: Moving from second-in-command to pilot-in-command on the same aircraft type
• Differences training: Required for variations of an aircraft you're already qualified on
• Requalification training: Needed if you've let your currency lapse

Understanding these distinctions helps pilots know what training requirements apply when changing aircraft or positions.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*