Date: 202011
Local time of day: 0001-0600
Flight conditions: Mixed
Light: Night
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Fuselage
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Fatigue; Distraction; Confusion; Communication Breakdown; Troubleshooting; Workload
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Vehicle
Detector: Person Maintenance
When detected: Aircraft In Service At Gate
Result: General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Procedure; Human Factors; Aircraft; Weather
Primary problem: Procedure

Narrative: I was involved in an Aircraft Damage event. The work assignments for myself and coworker was a rather heavy. We had two aircraft that were loaded with MELs that required Troubleshooting. The night was chilly with heavy winds. My coworker and I were dealing with an aircraft that came in with an NGS degraded inbound and an Autobrake MEL with history that we were trying to T/S to the correct fix. The autobrake MEL was taking a considerable amount of time and we were having difficulty finding the issue using the FIM. We decided to return to the shop to run some questions through our leadership. We were asking our leaders for some suggestions because Company said that a SYMD was needed to fix the AC but we could not find it listed at all in the FIM. While we were having this discussion another lead starts chiming in just replace the SYMD because Company said it was what was needed. We were trying to avoid replacing that unit because it would require more maintenance task to be performed. If it wasn't going to fix the issue we didn't want to create more work for ourselves. He was insistent on us changing the SYMD and making the comment that we shouldn't be overthinking this. This ended up making me flustered so we went back to Aircraft X and changed the SYMD. It did not fix the issue so now we had created more work for us for no reason and just added more internal pressure to myself because we were getting behind on our work and it was getting late in the night so we decided to separate and I drove over to Aircraft X which was on a remote pad instead of being on a gate like the Matrix stated. This just created more annoyances to distract me. I finally get to Aircraft X and meet up with our Tech Foreman to get direction on the CPC MEL that was scheduled to be cleared tonight. We had a discussion that he was going to take the CPCs and download the EVM data to find out which CPC was INOP since they both were BIT checking good. I was just going to wait at Aircraft X until he came back with the results. This ended up taking quite a bit of time and I get a phone call from leadership asking where my coworker and I were at with our assignments. I told him that two of our four planes were completed that they just required paperwork to be turned in. I told him that the other two were still in work and that my partner and I separated to try and get both aircraft done. I asked him if he would like me to leave Aircraft X and head back to the shop and he said yes because it was [late in the day] and he was being asked about the paperwork. I said no problem I'll go back to the shop and submit the other two airplanes. After the paperwork was submitted I checked in with the Tech Foreman and he told me that the #2 CPC needed changed due to an internal fault. No problem I thought. As I am walking away leadership asks me how long will it take to complete R/R the CPC and Ops Checks. I said I don't know maybe 30 minutes. He said okay. I go back to aircraft and looked at the time and realized it was starting to get really late in the night. I jump out of my High Speed Tug and thought I had set the parking brake. I jump up into the E/E and start installing the CPCs. As I am sitting in there the plane rocks a little bit. I thought nothing of it because tonight it was extremely windy and I just assumed that it was just another super gust since all the planes were rocking tonight. When I get out of the E/E I noticed that the Highspeed had rolled into Aircraft X with the rubber guard on the cab touching the plane. I panicked and jumped into the Highspeed and backed it away and looked at the area of the airplane and didn't initially see damage. I thought I had gotten lucky and that the cab bumper saved the aircraft from damage. I went into the airplane and finished the Ops checks to the CPC and cleared the MEL. The thought of what happened was still in my head so I checked the area again noticed that there was damage to the aircraft. I then went back to theshop and notified my leadership. I was instructed to map out the damage so I did. After that was completed I turned the results of the Map over to Dayshift.




Synopsis: Technician reported being distracted and frustrated caused him to forget to set the parking brake on an aircraft tug; causing the tug to roll into the aircraft; causing ground damage.