Service tube locking device

A turbine exhaust case of an aircraft engine, comprising:

• an outer duct wall and an inner duct wall defining an annular gas path therebetween;
• a strut extending across the annular gas path;
• a service tube extending along a tube axis within the strut, the service tube having a threaded inner end portion and an outer shoulder adjacent to the threaded inner end portion, the outer shoulder having a frustoconical shoulder face converging towards the tube axis and away from the threaded inner end portion;
• a bearing housing disposed radially inwardly from the inner duct wall, the bearing housing having a threaded bore, the threaded inner end portion of the service tube threadingly engaged to the threaded bore, the bearing housing having a seat face converging towards the service tube and towards the threaded end portion;
• a locking member extending from a first end to a second end, the first end including a notch receiving the outer shoulder of the service tube, the notch circumscribed by a frustoconical notch face abutting the frustoconical shoulder face to create a frustoconical-to-frustoconical contact surface between the locking member and the outer shoulder of the service tube, the second end in abutment against the seat face of the bearing housing;
• and
• a mechanical fastener threadingly engaged to the bearing housing, the threaded fastener tightened to press the locking member against both of the frustoconical shoulder face and the seat face.