What is an STC in aviation?

An STC, or Supplemental Type Certificate, is a key document in aviation that signifies that the FAA has approved modifications to an aircraft's design that differ from the original type certificate. This typically involves alterations or additions to the aircraft's systems, structure, or equipment affecting its performance or safety. The STC allows for the legal incorporation of these changes, ensuring that the aircraft continues to meet safety and operational standards after the modifications.

Understanding the significance of STCs is essential for pilots and operators since they provide a formal approval structure for changes and enhancements that might improve functionality, safety, or compliance with new regulations. They play a crucial role in maintaining the airworthiness of modified aircraft and ensuring that any alterations are duly documented and inspected.

In contrast, the other choices represent concepts or documents that do not accurately define an STC. For example, while a type certificate involves the original design of an aircraft, it does not cover modifications in the way an STC does. Flight hour records pertain to the operational history of an aircraft and not its design alterations, while certifications for flight instruction are related to pilot qualifications rather than aircraft modifications.