December 6, 201510 yr I've experienced this twice now- maybe three times, on different routes. I was enroute KPHL-KDTW climbing through FL320 when the autothrottle rolled the throttles back to idle. This happens both when the autothrottle is driven by the FMC data and also when driven by the MCP panel value. Once I cancel the autothrottle, I can operate the engines normally via manual control. The ice protection was activated (in automode as usual) if I remember correctly. Has this happened to anybody? Is it related to the cold? I believe the OAT was about -3 celsius when it occured. I did a search but could not find anything related to this topic. Or is it simply a bug?
