Definition
An unintended electrical discharge that jumps across an insulating surface or air gap inside a magneto distributor or ignition harness, causing the high-voltage spark to arrive at the wrong cylinder or to leak to ground instead of firing the intended spark plug.
Plain English
High-voltage electricity inside the ignition system jumps the wrong way, sparking where it shouldn't and missing where it should.
Context Anchor
Seen in aircraft engine ignition maintenance, especially when inspecting spark plugs, ignition leads, distributor parts, or other high-voltage ignition components.
Derivation
From 'flash' (a sudden burst of light or electricity) and 'over' (across). The word literally describes a spark flashing across a gap or surface it was not meant to cross.
Why Pilots Care
Can produce weak or erratic sparks that cause engine misfires, roughness, or failure to start, directly affecting safety and reliability.
Analogy
It is like a tiny lightning jump inside the ignition system: the electricity finds an easier wrong path instead of staying on the path designed for it.
Intuition Check
Flashover does not mean an engine fire or fuel flashing into flame here. In this maintenance context, it means an unwanted high-voltage spark jumping across the wrong path.
Example Sentence 1
Carbon tracking on the distributor block can lead to flashover, sending the spark to the wrong cylinder and causing the engine to run rough.
Example Sentence 2
Flashover in the ignition lead prevented reliable spark delivery to one cylinder.