Definition
An error in a radio navigation signal caused by conditions at or near the ground station transmitter site, such as nearby terrain, structures, vegetation, or other physical features that distort or reflect the transmitted signal before it leaves the area.
Plain English
A navigation signal error caused by things around the transmitter on the ground — like buildings, trees, or hills — that bend or bounce the signal as it leaves the station.
Context Anchor
Seen in instrument flying discussions about ground-based radio navigation signals and the limits of their accuracy.
Derivation
Site' comes from the Latin situs, meaning 'position' or 'location.' Here it refers specifically to the location of the ground transmitter — so a site error is an error that originates from conditions at that location.
Why Pilots Care
Certain stations have published site error tolerances; pilots must cross-check navigation sources when flying near affected radials or approaches.
Analogy
It is like hearing an echo in a room: the speaker said the words correctly, but the room changed how they reached your ears.
Intuition Check
Site error does not mean the pilot chose the wrong airport or the station was installed by mistake. It means the station’s surroundings are affecting the radio signal.
Example Sentence 1
The instructor explained that a slight course needle deflection near the VOR could be a site error caused by terrain close to the transmitter.
Example Sentence 2
Site error increased when the aircraft flew low over hilly terrain near the VOR station.