Definition
A data communications network in which messages are broken into small units called packets, sent independently across shared network paths, and reassembled at the destination. In aviation, PSNs underlie many ground-based data link services, including portions of the systems that deliver flight plans, weather, and air traffic services digitally.
Plain English
A network that sends information by chopping it into small chunks, routing each chunk through whatever path is open, and putting them back together at the other end.
Context Anchor
Seen in aviation communication, weather, and information-system references where data is sent between computers rather than spoken by radio.
Derivation
Packet comes from the idea of a small package — a parcel of data. Switched means the network chooses (switches) the route for each packet rather than holding open one fixed line. Together: a network that moves data in small parcels along whichever path works at the moment.
Why Pilots Care
Most modern aviation data services — flight plan filing, digital weather, ATC messaging — ride on packet switched networks. Knowing the term helps pilots understand references in technical documentation and system descriptions.
Analogy
Like mailing a long letter by tearing it into numbered postcards, sending each one through whatever postal route is fastest, and letting the recipient staple them back together in order.
Intuition Check
Do not read PSN as a special aviation radio channel. Here, it means a computer data network that moves information in small pieces.
Example Sentence 1
The flight service system exchanges weather and flight plan data over a packet switched network.
Example Sentence 2
Digital weather and traffic information reaches the cockpit through a packet switched network.