Plain English Meaning
All the outside help a pilot uses to plan and fly a trip — things like navigation signals, weather updates, radios, charts, and air traffic control — combined with the equipment in the cockpit that makes use of them.
Full Definition
The collective set of ground-based and airborne systems, services, and tools that assist pilots in planning, conducting, and completing flights safely and efficiently. In the instrument flying context, this includes navigation aids, communication networks, weather information services, flight planning resources, air traffic control services, and onboard electronic systems that support situational awareness and decision-making.
Context Anchor
Seen in the when discussing the that supports instrument flying and helps manage the , especially when are .