Originally Posted by
Sig229
I'm not trying to be a jerk, but you're really freaking out over 25 degrees? I've never heard of any requirement for engine parameters to match up exactly, and in almost no case will they unless both engines are identical in every way. The split you're seeing could easily be explained by a minor difference in wear, bleed valve position, temperature probe condition, etc. I've seen a 100C difference in the 737 during cruise, as you can imagine airlines swap engines all the time so it would be easy to have a mix of old and new. Now if you were seeing that much difference (or more) in new(er) engines, or if you suddenly went from a small split to a large one with no explanation it might be worth looking into. But if it's only 25 degrees and doesn't change wildly then there shouldn't be any concern.
And again no offense, but trying to match ITT and therefore throwing N1 and N2 out of whack is just comical. Besides making the airplane out of trim as you mentioned, having the engines out of sync and the resulting wah wah wah had to be quite annoying!
Actually, yeah, it is frustrating... Many power settings are to a temp, and that means either accepting a difference or not. These two engines have common history, the other plane with common history matches remarkably, as in pretty much exactly.
In the end we respect the ITT limits but set equal N1s with one engine as a master, this clunker having no sync for the reasons you note, but look for reasons that the display is as it is.