According to a current OAG statistic a Saab 2000 operates 6 times weekly on a sector of 900-999nm. Unfortunately the statistic does not reveal which airline or route it is. I have checked the websites of several airlines such as Blue1, Lithuanian, Carpatair etc. but could not find any airline with such a long sector. The longest I knew of was Golden Air's Saab 2000 from Stuttgart to Helsinki last summer, which is a Great Circle Distance of 885nm. Even sectors like Vilnius-Brussels are less than 800nm.
So maybe anyone here has an idea which route could be more than 900nm?