Technician reported errors in communication and procedures during a field trip to repair and recover a Eurocopter AS 350 with a main gear box chip detector light illuminated.

Narrative

This is the best of my recollection of this event on Day 1. I Received a call from the night pilot around XA:00 AM reporting a Main Gear Box (MGB) chip light came on during flight; and the pilot performed a precautionary landing in a grass field. I arrived on the scene around XA:45 AM. To my knowledge the Manager and my Maintenance Lead were informed at the time of the incident. I reviewed the logbook for a discrepant entry; and there was not one written for the current fault. I opened my laptop and setup my phone as a hotspot for internet. The service in the location was not the best; but eventually I was able to see the workbook. This is the first MGB chip light incident I have had. The fault found was the lower electrical chip detector of MGB had a singular magnetic scale that was less than the prescribed limits. I had the Pilot perform a ground run to make sure the chip detector would remain off. I told the Pilot that I felt the issue was resolved and he may return to base. Due to my lack of sleep and awareness; I did not inform Maintenance Control of the event; nor the aircraft was placed out of service; and the logbook did not have the proper entries. I feel that my lack of experience with chip lights; my awareness was lacking at the time of the event; and following up with maintenance control to ensure the work performed was recorded; I would need additional training on the Companies policies and procedures as well as ensuring that the proper entries in the logbook are created before starting maintenance; as well as having the aircraft properly removed from service through our Maintenance Control.