A medical helicopter pilot reported aborting a flight when he got a transmission chip light.

Attributes
ACN	1008376
Time
Date	201205
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	EC135
Operating Under FAR Part	Part 135
Flight Phase	Descent
Component
Aircraft Component	Helicopter Gearbox and Drive
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

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.

Original NASA ASRS Text

Title: A medical helicopter pilot reported aborting a flight when he got a transmission chip light.

Narrative: 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.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.