The engine may not develop enough bleed air at idle to effectively heat the protected surfaces. In some airplanes you might have to have a rather high power setting to prevent ice formation. The Falcon 20 requires about 82% in some cases, and you have to use your airbrake to descend without breaking speed limits. The TFE in the Lear 35 was also susceptible to ice forming on the back side of the fan blades at idle thrust in freezing fog and had a notice to avoid prolonged descents at idle thrust in icing conditions. In a idle descent we would blip the throttle every 4-5 min to break off any ice before it could grow to a size that could damage the engine, but most of the time we would be through any layers before it ever became an issue.
Some planes have heated static ports and some don’t require it, just depends on the location and how ice forms around it, not sure about the C-101 or how the ice accretion is modeled vs real life.
