That 100%-102% N2/NR switch has given us food for though recently, it just happens that around here on hot days our first limitation is TOT on the 109E, AND going up to 102% pushes the TOT quite a bit, so my and a colleague were discussing the "what if" we took off with 100% instead of 102% every now and then to avoid being limited by the TOT sooner than necessary.
If my memory serves me right, going up to 102% is not in the limitations section but rather in the Norm Procedures so it is not mandatory (or is it not?).
But my question is . . . . . what is the benefit of being at 102 instead of 100?
Two benefits that come to mind are . . . .
- Having a little higher N2 RPM during an Eng Failure, thus having a little more time to spare in case of
- Having more TR RPM's thus having more TR authority, which with the older metal blades is not really an issue as they have much more authority than the new composite blades.
But I wonder if having 102 at TO will improve lifting ability vs. 100? To me it's the contrary as you will reach the engine limits faster and will be unable to pull more pitch with out exceeding something.
Opinions and thoughts?