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N1% flight idle too high and throttles unsettled at cruise

Started by helloo, December 11, 2019, 01:45:08 pm

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Hello, my N1 idle seems too high. For descent it is usually around 45% which makes slowing down difficult. The EICAS also states it is still in the CRZ setting while descending.

Also, my CFY motorized throttles dance back and forth once cruise is reached. Each throttle moves back and forth about an inch non-stop while the power setting is stable on the EICAS. Any suggestions?



How are you descending, what mode are you using on the MCP?

CRZ setting just is the MAX N1 the EEC will allow the engines to go to, not the auto throttle command mode. A/T command mode is on the left hand side of the PFD.

(Assuming a 737)

Chief Pilot
Worldflight Team USA


I have LNAV and VNAV active.  However, once I reach cruise I disable the auto throttle since it is annoying the way it moves the throttles on the quadrant.  I just manually set the throttle.  If I reengage the auto throttle at TOD nothing changes as the N1 at idle stays at 45%. 


Another issue and not sure if it is related.  I noticed my TOD time is after the estimated arrival time.  Not sure why there is this discrepancy? 


A couple of things on the N1 for decent. If the anti-ice is on, you will have a higher idle thrust setting. I don't think it would be that high though.
The auto throttle could also be in throttle hold mode(standard descent operation for a 737), and if your throttle handles are not in the idle position, it would be taking their present input as the thrust setting.

I'd really have to go through your CDU legs pages to figure out the T/D problem.

Is this PM, ProSim, SimAvionics, or iFly avionics package?


Chief Pilot
Worldflight Team USA



Okay.....some basic troubleshooting....

Is this a new installation of SimA or did you update from a previous version?

If you did update from a previous version....was it all working correctly previously?

Make sure you are using the latest version which is 1.961.

When you installed/updated SimA did you do the parameter default reset procedure as specified in the update instructions? This is important with each new update.

Are you using one of the SimA aircraft in P3D?  Those are the only aircraft that will work properly with SimA.

Do you have the correct aircraft.cfg defined in the SimA server?  That aircraft file must match the SimA aircraft selected in P3D (for example, 737 vs. 777 etc.)

Your erratic TQ operation is most probably due to the larger issue that you are experiencing.  If not, you can stop the throttle "hunting" by widening the null range for throttle performance in your TQ software.  I am not familar with your TQ, but look for a value you can modify in the interface or change this value directly in the software code.

If you still have problems after all that I suggest that you address this question in the FDS SimA would be better addressed in that forum.

Fred K
Boeing 737NG-800, Prepar3D v4.5, Sim-Avionics 1.964, SimSync multi-channel (curved screen), Optoma 1080GTDarbee projectors (3), Fly Elise warping, FSGRW weather, FDS OH panels and CDUs, SimParts MIP, FDS SysBoards (OH), CPFlight MCPPro and pedestal panels, FI Gauges, PFC controls, converted motorized TQ (SIOC), Weber seats

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