Commercial Fixed Wing
Maintenance Powerplant; Maintenance Airframe
Communication Breakdown; Distraction; Time Pressure
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed; General Maintenance Action
Incorrect / Not Installed / Unavailable Part; Human Factors; Aircraft; Procedure
I was assigned Aircraft X for a service check and some write ups overnight at ZZZ. I was tasked by my fellow coworkers to do exterior tasks on the service check. Once I was finished; one of my coworkers that was in his words was 'teaching me how to work and do stuff right' asked me to change the oxygen bottles and all night was giving me a bit of a hard time. I asked him if that was ok since I'm not [procedure] qualified and he answered yes. He had already printed out the R&I (Remove and Install) for the oxygen. I read the task and said to go upstairs bleed the system on the First Officer side; pull the circuit breaker; and close the bottle. I Followed the AMM on the R&I; I installed the bottle and noticed the bottle was different than any other bottle I've changed out before. As I installed the bottle and started turning the cylinder slowly; I was leak checking it; I continued turning the cylinder to a stop and felt it get tight after a couple rotations and being safe with the cylinder since it was made out of composite and felt fragile. I told my coworker I was done and he stepped inside to look over my work; I felt adequate the bottle was good because someone checked my work. Once I was finished the same coworker (the same guy giving me a hard time) asked me to close up quick and do the parts tag. As I was finishing up the putting the oxygen bottle into the stores vehicle; they had already pulled the stairs to the aircraft and was ready to push back and taxi to the gate. I followed the aircraft into gate XX and wing walked; chocked; plugged in GPU; and did a walk around after the taxi. As I finished that at the gate I proceeded to run up the get bridge as my fellow coworker that was 'teaching me' asked why I was going up stairs and I said 'to put in the circuit breaker and make sure everything was ok. He said I already did that; EVERYTHING IS OK. After my experience was questioned I felt confident when he said everything was ok.
Technician reported that distraction and pressure from a coworker resulted in a procedural error and installation of an incorrect oxygen bottle.