An avionics mechanic reports on the difficulty reading the wire identification markings in the forwa...

Narrative:

Inspected and attempted to make wire identification list of affected wires. Gave list to lead on duty for operations check processing. Secured bundle; sold to inspection. Wires were difficult for me to read. At the time I believed if I read any wires wrong; they would not show on the wire list for processing operations checks.callback conversation with reporter revealed the following information: reporter stated that at least three; heavy gauge electrical wires; for the center electric hydraulic pump (C-2) had overheated; shorted and arced. The overheated wires became so hot; that a cabin floor beam was damaged and required structural repair. Although the cabin floor beam was repaired and inspected; the required inspections and listings of all affected wires and wire bundles damaged by the shorted C-2 pump wires; had not been accomplished. Many of the wires affected by the shorting and arcing of the C-2 electric pump wires; required environmental splices that had not been listed or identified by the line station that had previously accomplished the electrical repair work.

Original NASA ASRS Text

Title: An Avionics Mechanic reports on the difficulty reading the wire identification markings in the forward cargo pit ceiling of a B777-200. A hydraulic pump wire bundle had overheated; shorted and arced and damaged the cabin floor beam.

Narrative: Inspected and attempted to make wire ID list of affected wires. Gave list to lead on duty for operations check processing. Secured bundle; sold to inspection. Wires were difficult for me to read. At the time I believed if I read any wires wrong; they would not show on the wire list for processing operations checks.Callback conversation with Reporter revealed the following information: Reporter stated that at least three; heavy gauge electrical wires; for the Center electric hydraulic pump (C-2) had overheated; shorted and arced. The overheated wires became so hot; that a cabin floor beam was damaged and required structural repair. Although the cabin floor beam was repaired and inspected; the required inspections and listings of all affected wires and wire bundles damaged by the shorted C-2 pump wires; had not been accomplished. Many of the wires affected by the shorting and arcing of the C-2 electric pump wires; required environmental splices that had not been listed or identified by the Line station that had previously accomplished the electrical repair work.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	825454
Time
Date	200902
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B777-200
Operating Under FAR Part	Part 121
Flight Phase	Parked
Component
Aircraft Component	Hydraulic System Pump
Person 1
Function	Technician
Qualification	Maintenance Airframe Maintenance Powerplant
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural FAR Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy

An avionics mechanic reports on the difficulty reading the wire identification markings in the forward cargo pit ceiling of a B777-200. A hydraulic pump wire bundle had overheated; shorted and arced and damaged the cabin floor beam.