Narrative:

In the boeing 737 standard wiring practices manual; document number D6-54446; chapter 20-10-30; repair of electrical wire and cable; page 6 states; 'the maximum number of splices that a wire can have is three.' how can we possibly be held to this standard when there is no system in place to track if previous splices were performed? For example; recently I was working a water quantity indication problem. The wire that turned out to be damaged was W298-067-22; which is 129 ft long (reference wdm 38-41-01 and wire list 91-21-11 section W0290; page 2). Two splices were installed on the wire to fix the problem and so according to the swpm; only one more splice is permitted. But the reality of it is that after 360 days; which is as far back as you can search in the computer; no one will know about those two splices. Callback conversation with reporter revealed the following information: the reporter stated the B737 standard wiring practices manual states clearly the maximum splices allowed in any one wire is three. Reporter knows of no records that will match wire numbers to splices and believes this is the way it is in the industry. Reporter stated that this airplane was built in 1988 and has gone through numerous heavy maintenance checks where wiring has been added for modifications. Reporter stated that there are only two sits that require the individual wire number to be recorded: first; when a connector is modified; and second; when a spare wire is utilized.

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Original NASA ASRS Text

Title: AN ACFT WIRE WAS REPAIRED WITH A SPLICE PER THE MANUFACTURER WIRING PRACTICES MANUAL. THE MANUAL STATES; 'THE MAXIMUM NUMBER OF SPLICES IN A SINGLE WIRE IS THREE.' HOWEVER; INDIVIDUAL AIRLINE MAINT PRACTICES VARY ON THE METHODS AND PROCEDURES USED TO TRACK WIRING SPLICES.

Narrative: IN THE BOEING 737 STANDARD WIRING PRACTICES MANUAL; DOCUMENT NUMBER D6-54446; CHAPTER 20-10-30; REPAIR OF ELECTRICAL WIRE AND CABLE; PAGE 6 STATES; 'THE MAXIMUM NUMBER OF SPLICES THAT A WIRE CAN HAVE IS THREE.' HOW CAN WE POSSIBLY BE HELD TO THIS STANDARD WHEN THERE IS NO SYSTEM IN PLACE TO TRACK IF PREVIOUS SPLICES WERE PERFORMED? FOR EXAMPLE; RECENTLY I WAS WORKING A WATER QUANTITY INDICATION PROB. THE WIRE THAT TURNED OUT TO BE DAMAGED WAS W298-067-22; WHICH IS 129 FT LONG (REF WDM 38-41-01 AND WIRE LIST 91-21-11 SECTION W0290; PAGE 2). TWO SPLICES WERE INSTALLED ON THE WIRE TO FIX THE PROB AND SO ACCORDING TO THE SWPM; ONLY ONE MORE SPLICE IS PERMITTED. BUT THE REALITY OF IT IS THAT AFTER 360 DAYS; WHICH IS AS FAR BACK AS YOU CAN SEARCH IN THE COMPUTER; NO ONE WILL KNOW ABOUT THOSE TWO SPLICES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE B737 STANDARD WIRING PRACTICES MANUAL STATES CLEARLY THE MAXIMUM SPLICES ALLOWED IN ANY ONE WIRE IS THREE. RPTR KNOWS OF NO RECORDS THAT WILL MATCH WIRE NUMBERS TO SPLICES AND BELIEVES THIS IS THE WAY IT IS IN THE INDUSTRY. RPTR STATED THAT THIS AIRPLANE WAS BUILT IN 1988 AND HAS GONE THROUGH NUMEROUS HEAVY MAINT CHKS WHERE WIRING HAS BEEN ADDED FOR MODIFICATIONS. RPTR STATED THAT THERE ARE ONLY TWO SITS THAT REQUIRE THE INDIVIDUAL WIRE NUMBER TO BE RECORDED: FIRST; WHEN A CONNECTOR IS MODIFIED; AND SECOND; WHEN A SPARE WIRE IS UTILIZED.

Data retrieved from NASA's ASRS site as of January 2009 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.