Date: 202006
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Horizontal Stabilizer Trim Motor
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Confusion; Training / Qualification; Workload
Second reporter function: Technician
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Human Factors; Procedure; Aircraft; Company Policy
Primary problem: Procedure

Narrative: I had just gotten done with my previous task when I needed something else to do around XA00. I looked at [Mechanics App] to see that the horizontal stabilizer gearbox lube needed to be complied with. So I went and grabbed a scissor lift and all my tools and consumables. I recently learned that the spanner tool that we use to remove the grease port sealing cap is not considered to be a tool but it's considered to be a part. I had to ask the stores clerk multiple times before I was able to obtain the tool. I serviced the HSTA gearbox In accordance with CRJ 900 AMM (Aircraft Maintenance Manual) task 12-XX-XX-XXX-XXX-XXX. I used the horizontal stab trim switch to rotate the gearbox; but I did not manually rotate the input shaft like the task says to do. My thought process was that I would just rotate the gearbox by cycling the horizontal stab all the way up and down 3 times instead of manually rotating the gearbox clockwise and counterclockwise with the hex socket and it would save me some time. My common sense tells me that this would rotate the equipment inside the gearbox so that I wouldn't have to rotate it manually. In order to spread the grease around thoroughly; I cycled the horizontal stab up and down 3 times to satisfy the AMM requirements of procedure 6 in the AMM task 12-XX-XX-XXX-XXX. I hadn't suspected that I had done anything wrong until the next night on shift when I was approached by my inspector.Insufficient training.I am still asking the question how this could be a safety violation and would appreciate some extra clarification or training on the subject.Have the brand new employees do more than just 3 days and RONS for the first 6 months. Have them do big jobs like this one where they can be more challenged and doing something new when they are with a maintenance training instructor. The Company already does this however; and the new sign behinds are getting on really big jobs early on. Has to do with the new employees level of experience.


Second narrative: Aircraft X had a HSTA Gearbox lubrication scheduled; Task reference CRJ900 AMM (Aircraft Maintenance Manual) 12-XX-XX-XXX-XXX-XXX. I had signed up for the task to start it but we did not have the tooling to complete the task; I AOG (Aircraft on Ground) requisitioned this tool and unassigned myself from this task. The next day I saw [other Mechanic] had signed off the task. I asked him how it went with the tool; and how it went with a part in the task where it requires you to turn the channel motor shafts a certain amount of revolutions one way then back another. And his reply to me was he did not turn the motor shafts any revolutions; and to spread the grease he just moved the horizontal stab up and down however many revolutions. That alarmed me because this task is very specific for a very; VERY FLIGHT CRITICAL item. Our conversation only lasted a minute or so and I got pulled away and remembered that conversation about 10 minutes prior to clocking out. With the tool he used; the tool is only required for removing the grease port sealing cap for access to lubrication. My biggest concern is the steps that he skipped were the ones within step 6 of the actual lubrication task. I had approached inspection and the supervisors on duty at the end of my shift; I was informed by Inspection to fill out [a report].Make any maintenance that is done to the HSTA RII


Synopsis: Technician reported insufficient training as the factor in not following procedures during a horizontal stabilizer jackscrew lubrication.