EC135
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport
Aircraft
Had a patient flight request to [local] hospital. Flew to partner hospital; picked up the flight nurse and departed for [local] hospital. While enroute we encountered light turbulence. Within a few seconds from the encounter I noticed the 'Master Caution' light. Checked the CAD panel to find we had a transmission chip caution light. Aborted flight and returned to base with no further incidents.
A medical helicopter pilot reported aborting a flight when he got a transmission chip light.