MBK117 air ambulance pilot reported maintenance failure to install tail rotor gearbox bolts after maintenance action. Pilot reported management pressure to get helicopters back online lead to maintenance errors.

Narrative

MX preformed a TR (Tail Rotor) track and balance on Day 0 when they removed their equipment; they failed to replace the bolts that held that equipment on the T/R gearbox. On Day 2 while pre-flighting the helicopter I wrote up the starter light; the helicopter was out of sight (OOS) for the next 2 days. On Day 4 after pre flight I received 4 patient flights through out the day. On Day 5 I was notified that MX found 2 missing bolts on the T/R they failed to replace after they removed the T/R vibe gear. Suggestions: MX that did the Required Inspection Item (RII) should be more diligent on their checks and the new mechanic needs to ask more questions on what should be replaced after removal of testing equipment. Less pressure on MX to get the helicopter back in service because managers are worried about there OOS times because they affect their KPI's (Key Performance Indicators). Torque stripping bolts to make them easier to see on walk arounds. I'll be looking at all bolts and fasteners during walk arounds.