IAE 2500-A1 N1>n2

[flyabovecloud]

got one question above RPM.

I had one flight from CMB to AUH, The aircraft climb above OPT ALT. I found both engine N1>N2, anybody knows why?

Thanks in advance.

[barit1]

Very high TAT?

(PS - Even though the percent indication for N1 appeared greater than N2, the 100% references for the two are very different. Trust me, if you did the math, N2 was still much greater than N1) :8

[flyabovecloud]

SAT is -43, i am not sure about TAT, actually this is very old engine, IAE 2500-A1.

[srilion]

barit1 is correct, you cannot compare N1 vs N2. It is a percentage value of rated N1 or N2. Seen this many a time on type :)

[barit1]

If SAT is -43, then TAT will be in the vicinity of -15 or -16 which does seem pretty high.

[flyabovecloud]

I will ask you more people, thanks a lot