Definition
High-voltage electrical power cables suspended above the ground between tall support towers or poles, used to carry electricity over long distances. In aviation, they are a significant low-altitude obstruction hazard, particularly during takeoff, landing, low-level maneuvering, and operations near unimproved or rural areas.
Plain English
The big power lines you see strung between tall towers across the countryside. From the air, they can be very hard to see — and hitting one is often fatal.
Context Anchor
Pilots may encounter overhead transmission lines while planning or flying takeoffs, landings, emergency landings, low passes, or night operations near roads, fields, and airports.
Derivation
“Overhead” means above the ground or above a person. “Transmission” comes from the idea of sending something from one place to another. Here, it means sending electrical power through wires, not radio communication.
Why Pilots Care
Striking these lines remains a leading cause of fatal low-level accidents because they are difficult to see until very close.
Grounding Statement
If you see poles or towers lined up across a road or field, assume wires may be stretched between them even if you cannot see the wires clearly.
Intuition Check
“Transmission” here does not mean a radio transmission or aircraft communication. It means electrical power being carried through wires above the ground.
Example Sentence 1
While flying a low pass over the field, the pilot spotted the support towers on either side of the road and climbed well above the overhead transmission lines before continuing.
Example Sentence 2
Sectional charts show overhead transmission lines with a specific symbol so pilots can plan to cross them at a safe angle and height.