Eurocopter AS 350/355/EC130 - Astar/Twinstar/Ecureuil
Maintenance Powerplant; Maintenance Airframe
Situational Awareness; Distraction
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors
During the normal 30day/100hour hydraulic fluid change; while system was draining; I removed and serviced [the oxygen system] bottle and reinstalled. I then finished the servicing of the hydraulic system. I then signed off the pre-completed logbook page for the hydraulic system service. The pilot did the inspection of the hydraulic system and signed the log page. We then proceeded to move the helicopter out of the hangar. I had forgotten to mention the servicing of the [oxygen bottle] to the pilot and I did not remember to write up a discrepancy for the servicing of the [oxygen]. The next time the helicopter flew the crew had a warning on the ventilator of low pressure. The ventilator and attaching lines were checked; all good. The pilot checked the [oxygen] bottle and found the one feed line not connected.
The Maintenance Technician did not record an oxygen discrepancy on an AS350. He also did not complete the bottle installation after servicing; which led to a low pressure condition.