Date: 201910
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Wheels/Tires/Brakes
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Lead Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Distraction; Situational Awareness; Time Pressure; Workload
Anomaly: Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Routine Inspection
Result: General None Reported / Taken
Contributing factors: Procedure; Human Factors; Staffing
Primary problem: Staffing

Narrative: I was the only Lead Technician for the line starting out in the morning. I was assigned in the booth to assign all the task for the inbound calls. I assigned two technicians to the B757 ETOPS routed planes. Aircraft Z arriving/leaving at XA:10/XB:45; Aircraft Y arriving/leaving at XC:32/XE:55 and Aircraft X arriving/leaving at XD:47/XF:35. Later that morning; Supervision brought a Lead Technician down from the hanger to work the line. I made him aware of all the ETOPS aircraft for the day. Aircraft Z went out flawless. Aircraft Y came in at approx. XC:32 and required a daily check; ETOPS PDC (Pre-Departure Clearance) and a MEL follow-up for MEL 25-XX slide engage light. During their check # 8 tire was found to be worn and required replacement. They proceeded to replace the tire but had difficulty getting it released from the brake. They ended up having to remove both the #8 tire and brake assembly together. During this time Aircraft X had landed at approx. XD:47. With everything going on Aircraft Y both myself; the ETOPS Lead; and the two technicians completely forgot about Aircraft X. After I was relieved from the booth at around XF:15 I heard over the radio that they were still having issues with the brake and tire change and required a spacer to be ordered to replace the old one that was stuck between the tire and brake. So I proceeded to a computer to help order the spacer for the aircraft. At no time did it occur to me that we didn't have anyone assigned to Aircraft X. I was notified later in the day that the check had been missed. It just happened to be the perfect storm. The day started out with just myself being the only Line Lead until later in the morning they sent a OTS (Out of Service) Lead down to help us. The OTS Lead isn't as familiar with our day to day operation at the line. Usually when the techs are stuck working on one plane they will call the booth so that we can send out more techs to help with the other ETOPS planes. We also usually have a specific ETOPS Lead assigned to ETOPS that would follow up with the techs and make sure paperwork is turned in. Like I said we did end up getting another lead that day but he wasn't as familiar with the line operation due to him being an OTS Lead.Make sure there are sufficient Line Leads that are qualified and understand the line operation. Have a redundancy procedure in place to verify that all assigned checks have been completed prior to ETOPS Departure.




Synopsis: Lead Technician reported that an ETOPS check was missed due to lack of proper supervision and workload with previous aircraft.