An airport has 2 runways: a Part 139 and a GA; this is a _______ in the Airport Certification Manual.

In the context of an Airport Certification Manual, when an airport has two runways designated as a Part 139 runway and a General Aviation (GA) runway, it indicates a specific operational characteristic that serves as a limitation. A Part 139 runway is designed for commercial service airports that must meet particular safety and operational standards as outlined by the FAA. In contrast, a GA runway does not have the same stringent requirements.

By identifying the configuration of runways in this manner, it highlights the operational limitations the airport faces given the differing regulatory standards associated with each type of runway. This affects the types of operations that can be performed and the facilities that are required to meet safety and operational standards.

While requirements, guidance, and regulations pertain to the standards that need to be met or followed, a limitation specifically denotes the inherent restrictions or specific operational capabilities that arise from the airport's configuration. Thus, characterizing the presence of a Part 139 runway alongside a GA runway as a limitation is accurate as it directly reflects the operational scope and regulatory framework within which the airport must function.