A321 CFM and A321 XLR Climb Thrust Issue

1st Official Post

    Does anyone else’s A321 and A321XLR (CFM and PW) climb with over 100% N1? I put the thrust levers to the climb detent after takeoff, and the flight computer steadily increases the N1 thrust until about 100.5%, which is more than was used for takeoff. It does this over the course of the climb. The cost index is 20, with a flex temp of 80 and any changes to wieght and weather have no effect. No issues with the A320 CFM and NEO.

    Aerofly FS Global version 1.6.7 | Ipad Air 5th Gen, 8gb Ram | IOS 26.6 | Touch controls with tilt

    Curious if anyone has experienced this…

    • Official Post

    100% N1 or N2 corresponds to a defined rotation speed of the engine and is not to be confused with the maximum allowed rotation speed.

    Depending on the engine type and rating plug the max N1 can vary e.g. between 80% or as high as 110%. Airlines can typically choose between different engine ratings which are then set in the engine rating plug, installed on the engine itself. Changing the engine plug can change the maximum thrust of the engine and has significant consequences for the takeoff and go-around performance calculations of course. Because of the similarity between engines and almost identical engine cores the engine manufacturers keep the same 100% N1 reference rotation speed but with new technology and materials the engine thrust can usually be increased for heavier aircraft such as the A321 and A321XLR.

    The current maximum allowed N1 and the start of the caution range is indicated on the ECAM engine display. As long as the values are in the green it behaves as it should and is within certified limits.

    Regards,
    Jan