Apples and oranges? What does the JT8 have to do with the CFM56? Of course the ignitors have a limited life, but the CFM56 is a lot more susceptible to water ingestion (especially during ground ops since they are hanging only a few inches over the ground on the 737s). There have been numerous flameout events in the CFM56 in heavy rain as well, so keeping them on during engine anti ice operation is just an extra precaution to keep the relatively (compared to the JT8) small core running going...
Last edited by STBYRUD; 29th October 2014 at 16:40.