Guarding or Guard

[Tukanja]

RGL is an acronym used in aviation.
Is either Runway Guard Lights correct form or Runway Guarding Lights or both?

Sparking Plug is a part of a vehicle ignition system.
Is either Spark Plug correct form or Sparking Plug or maybe both?

And what about this?

Runway Edge Lights
Runway Edging lights


Thanks

[Joe]

Runway Guard Light(s) seems to be the correct form. If I google "Runway Guarding Lights" (with quotation marks) the only unsponsored response is this page :)

RGL is an abbreviation, not an acronym. An acronym is a word made from the initial letters of other words, like laser (Light Amplification by Stimulated Emission of Radiation).

[Joe]

The normal form is spark plug. If you search Google for sparking plug you will see that the vast majority of results, including the first page, give spark plug.