Fix Boeing 737 engines staying above idle after landing in X-Plane 12 by checking autothrottle, hardware calibration, reverse thrust and add-on settings.
In X-Plane 12, a 737 engine will not fall to zero RPM after touchdown: idle is a running condition. If thrust remains above normal idle, the usual causes are a hardware throttle not reaching its calibrated stop, a duplicate axis, active autothrottle or TO/GA, reverse thrust, or add-on throttle logic.
Is the engine actually above idle?
The N1 indication, cockpit lever position and aircraft movement together show whether the engines are genuinely producing excess thrust. A 737 can continue rolling, or even accelerate slowly when light, with both engines at normal idle.
| What you see | Likely explanation |
|---|---|
| Both cockpit thrust levers are fully aft and N1 settles | Normal running idle; the engines are not supposed to stop |
| The cockpit levers move forward after touchdown | Autothrottle, TO/GA or a physical throttle axis has commanded thrust |
| Only one lever or engine remains high | Separate engine-axis calibration, a duplicate binding or an add-on configuration problem |
Reverse levers are raised or REV is indicated | Reverse thrust is intentionally increasing engine speed |
Do not judge idle from sound alone. Engine spool-down is not instantaneous, and the exact idle indication varies with conditions, system loads and the aircraft model.
Why does thrust return when the autothrottle disconnects?
Thrust often returns because a non-motorised throttle quadrant remains at the approach setting while the virtual autothrottle moves the cockpit levers. When the model gives control back to the hardware after landing, the virtual levers can jump to that higher physical position.
As the autothrottle enters its flare-retard phase, bring the physical throttles towards idle so they match the virtual levers. If moving the hardware overrides the autothrottle prematurely, disconnect the autothrottle and retard manually instead. Our guide to managing 737 thrust through the flare and touchdown explains the timing in more detail.
How do I fix 737 throttles that will not reach idle?
Start by checking the active thrust command, then isolate the hardware axis from the aircraft or add-on.
- Take manual control. On rollout, prioritise braking and directional control. Disconnect the autothrottle, ensure TO/GA has not been triggered, stow the reversers and move every physical throttle fully aft.
- Watch the cockpit levers. If they remain at idle but N1 settles above zero, that is normally running idle. If they move forward again, another axis, button or automation mode is still issuing a command.
- Recalibrate the throttle axes. In X-Plane’s joystick settings, move each lever through its complete range and confirm the live indicator reaches the idle endpoint without flickering. Add a small idle dead zone only when visible axis noise requires it.
- Remove duplicate assignments. Check every connected quadrant, joystick and gamepad. A generic
Throttleaxis can conflict with separateThrottle 1andThrottle 2assignments. Our engine-throttle assignment and calibration checklist covers this failure mode. - Check the reverse-thrust mapping. A latched reverse command or incorrectly mapped detent raises N1 rather than producing forward idle. Depending on the quadrant and aircraft, the reverse detent may need a button command instead of being treated as part of the normal throttle range.
- Compare aircraft. Test a new flight with the included 737 and a clean control profile. If both aircraft show the fault, concentrate on X-Plane’s assignments or hardware. If only an add-on is affected, inspect that aircraft’s throttle, reverser and noise-filtering options.
Should the 737 autothrottle retard automatically?
A detailed 737 model should command the thrust levers towards idle during the flare when the autothrottle, landing mode and required sensor inputs are valid. Some simplified models do not reproduce the real retard logic exactly, and the pilot must still verify idle thrust by touchdown.
If the expected retard mode never appears, check that the autothrottle is armed, the aircraft is correctly configured for landing and no TO/GA command has been activated. With the Zibo 737, also rule out damaged or mixed installation files by following the correct Zibo installation and update procedure.
Why does N1 remain above zero after parking?
Idle keeps the engines running; it does not shut them down. N1, N2, fuel flow and engine sound remain present until the fuel control levers are moved to cutoff during the parking or shutdown procedure.
Do not shut the engines down on the runway merely to obtain a zero indication. Set the parking brake, establish the required electrical and pneumatic supply, then use the normal sequence described in our 737 landing, parking and shutdown flow.