B777-200
Maintenance Airframe; Maintenance Avionics; Maintenance Powerplant
Maintenance Avionics 8; Maintenance Technician 15
Communication Breakdown; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Company Policy; Procedure; Incorrect / Not Installed / Unavailable Part; Human Factors
Mis-routed/poorly routed wires along with non-compliance securing of these wires that are critical to fuel systems proper function; were found during a C-Check Preliminary Inspection of a B777-200 aircraft. Two [Maintenance] Non-Routine write-ups were generated in order to re-route; replace; re-secure various wires related to the fuel systems found in and around two electrical Panels: P110 and P210. The particular wires that were found to be in non-compliance are the same wires that were previously worked on during the process of accomplishing two Airworthiness Directives (A/D) notes that were not done here at our Base Maintenance facility. The wires in question were routed outside the [electrical] bundles along with crossing over to adjacent bundles and found to be in non-compliance with the correct specifications as outlined in the A/D Bulletin. The AD notes are: Service Bulletin 5000ELM-28-454 and S/B 5000ELM-28-455. Contracted Maintenance. [Recommend] closer monitoring and follow-up of AD's; which are Flight critical systems; that may have been performed outside of our Air Carrier Maintenance Facilities.
Reporter stated what he found was the 'short changing' of the routing of specific Fuel System electrical wires that are suppose to be routed along already installed wire bundles. Instead; wire installers at a Foreign Heavy Maintenance Repair Station were 'Bundle Jumping'; a Non-Standard Wiring Practice where wires are routed outside secured wire bundles; and then jumped; (crossed-over) to other wire bundles. That was the condition of Fuel System wires in and around the P110 Left Power Management Panel and P210 Right Power Management Panels that had specific requirements for securing and routing noted in the two A.D.s and Service Bulletins he included in his report. The P110-P210 Power panels are part of the B777s Electrical Load Management System (ELMS) located in the Main Equipment Center (MEC).Reporter stated that twenty Airworthiness Directives (A/Ds) had been accomplished at a contracted Foreign Repair Station. He is looking for his Air Carrier's Engineering Department to initiate a Fleet Campaign on their B777 aircraft to inspect the wiring coming in and out of the P110 and P210 Power Management panels.
An Aircraft Maintenance Technician (AMT) reports finding critical fuel system electrical wires in and around the P110-P210 Left and Right Power Management Panels that were misrouted; poorly routed; crossing over to adjacent electrical bundles and not in compliance with two Airworthiness Directives (A/Ds) and Service Bulletins (S/Bs) for B777-200 aircraft.