What is the igniter used in gas turbine engine right now Air-gap igniter or Surface discharge igniter?and why?

Question

What is the igniter used in gas turbine engine right now Air-gap igniter or Surface discharge igniter?and why?

Answer 1

The GE Frame 5 (heavy industrial) machines that I've worked with since 1998 all used spark plugs, err....air-gap igniters.

(The difference between a spark plug and an air gap igniter is about a 10-fold cost increase to be put on the GE Approved Spares list.  That's all!)

Why?  Hmmm...probably because the machines don't require anything particularly fancy or high performance, just reliable and readily available if replacements must be scrounged locally (in the way back boondocks).