Narrative:

Wire routing appeared to be incorrect per engineering order. A fitting problem developed during movement of wiring. Referenced amm and discovered that original routing was correct. I realized that previous aircraft I'd worked the engineering order had been incorrectly routed when received; and after wrap and inspection of wiring; were returned to service as received per illustration on the engineering order. The engineering order does not show associated wiring to give proper orientation of wiring qef and qej to other wiring and clamp points. Too little information due to alteration of drawing for the engineering order.callback conversation with reporter revealed the following information: reporter stated his carrier's engineering group recently issued an amended (shortened) version of an original engineering order to inspect for chafing electrical wire bundles and support clamps in the vertical stabilizer. This amended engineering order required specific inspections of the two electrical wire bundles for the primary and trim electrical drive motors. If any discrepancy is found; the damaged bundle is to be inspected further and repaired if necessary and the wire bundle is to have an additional wrap with silicone tape; also known as 'guideline' tape and is generally red in color. Reporter stated a recent report of a horizontal stabilizer primary drive motor failure on an md-80 in the stabilizer compartment; due to a chafing and arcing wire bundle for the primary drive appears to be the reason why the amended engineering order has been issued. Reporter stated the two wire bundles for the primary and trim motors that are called out in the amended engineering drawing; are actually part of a wire bundle run of four electrical bundles near the top of the vertical stabilizer in an area known as the saddle. This is a transition area from horizontal stabilizer to the vertical stabilizer structure for the wire bundles. The automatic pilot stabilizer position sensor is in this area. The original engineering drawing showed four wire bundle runs; with positions noted as 1; 2; 3; 4 going left to right; facing forward. The stabilizer primary and trim motor wire bundles are in the left positions. The amended drawing only shows the two wire bundles associated with the stabilizer primary and autopilot trim motors. No reference is given for the other two wire bundles. So mechanics are moving the two motor drive bundles from the #1 and 2 left positions to a center #2-and 3 position; because they believe the two wire bundles they are specifically inspecting were in the wrong position. Repositioning these bundles affects the slack needed for some wire bundles affected by horizontal stabilizer movement. Reporter stated his carrier's engineering hasn't responded yet to his request for better wire bundle position drawings.

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Original NASA ASRS Text

Title: WHILE PERFORMING A SPECIFIC INSPECTION OF THE MD-80 HORIZ STAB PRIMARY AND TRIM MOTOR DRIVE WIRE BUNDLES FOR CHAFING IN VERTICAL STAB; MECHANIC REALIZES THE ENGINEERING ORDER'S DRAWINGS WERE INACCURATE.

Narrative: WIRE ROUTING APPEARED TO BE INCORRECT PER ENGINEERING ORDER. A FITTING PROB DEVELOPED DURING MOVEMENT OF WIRING. REFERENCED AMM AND DISCOVERED THAT ORIGINAL ROUTING WAS CORRECT. I REALIZED THAT PREVIOUS ACFT I'D WORKED THE ENGINEERING ORDER HAD BEEN INCORRECTLY ROUTED WHEN RECEIVED; AND AFTER WRAP AND INSPECTION OF WIRING; WERE RETURNED TO SVC AS RECEIVED PER ILLUSTRATION ON THE ENGINEERING ORDER. THE ENGINEERING ORDER DOES NOT SHOW ASSOCIATED WIRING TO GIVE PROPER ORIENTATION OF WIRING QEF AND QEJ TO OTHER WIRING AND CLAMP POINTS. TOO LITTLE INFO DUE TO ALTERATION OF DRAWING FOR THE ENGINEERING ORDER.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED HIS CARRIER'S ENGINEERING GROUP RECENTLY ISSUED AN AMENDED (SHORTENED) VERSION OF AN ORIGINAL ENGINEERING ORDER TO INSPECT FOR CHAFING ELECTRICAL WIRE BUNDLES AND SUPPORT CLAMPS IN THE VERTICAL STAB. THIS AMENDED ENGINEERING ORDER REQUIRED SPECIFIC INSPECTIONS OF THE TWO ELECTRICAL WIRE BUNDLES FOR THE PRIMARY AND TRIM ELECTRICAL DRIVE MOTORS. IF ANY DISCREPANCY IS FOUND; THE DAMAGED BUNDLE IS TO BE INSPECTED FURTHER AND REPAIRED IF NECESSARY AND THE WIRE BUNDLE IS TO HAVE AN ADDITIONAL WRAP WITH SILICONE TAPE; ALSO KNOWN AS 'GUIDELINE' TAPE AND IS GENERALLY RED IN COLOR. REPORTER STATED A RECENT REPORT OF A HORIZ STAB PRIMARY DRIVE MOTOR FAILURE ON AN MD-80 IN THE STAB COMPARTMENT; DUE TO A CHAFING AND ARCING WIRE BUNDLE FOR THE PRIMARY DRIVE APPEARS TO BE THE REASON WHY THE AMENDED ENGINEERING ORDER HAS BEEN ISSUED. REPORTER STATED THE TWO WIRE BUNDLES FOR THE PRIMARY AND TRIM MOTORS THAT ARE CALLED OUT IN THE AMENDED ENGINEERING DRAWING; ARE ACTUALLY PART OF A WIRE BUNDLE RUN OF FOUR ELECTRICAL BUNDLES NEAR THE TOP OF THE VERTICAL STAB IN AN AREA KNOWN AS THE SADDLE. THIS IS A TRANSITION AREA FROM HORIZ STAB TO THE VERTICAL STAB STRUCTURE FOR THE WIRE BUNDLES. THE AUTO PILOT STAB POSITION SENSOR IS IN THIS AREA. THE ORIGINAL ENGINEERING DRAWING SHOWED FOUR WIRE BUNDLE RUNS; WITH POSITIONS NOTED AS 1; 2; 3; 4 GOING LEFT TO RIGHT; FACING FORWARD. THE STAB PRIMARY AND TRIM MOTOR WIRE BUNDLES ARE IN THE LEFT POSITIONS. THE AMENDED DRAWING ONLY SHOWS THE TWO WIRE BUNDLES ASSOCIATED WITH THE STAB PRIMARY AND AUTOPILOT TRIM MOTORS. NO REFERENCE IS GIVEN FOR THE OTHER TWO WIRE BUNDLES. SO MECHANICS ARE MOVING THE TWO MOTOR DRIVE BUNDLES FROM THE #1 AND 2 LEFT POSITIONS TO A CENTER #2-AND 3 POSITION; BECAUSE THEY BELIEVE THE TWO WIRE BUNDLES THEY ARE SPECIFICALLY INSPECTING WERE IN THE WRONG POSITION. REPOSITIONING THESE BUNDLES AFFECTS THE SLACK NEEDED FOR SOME WIRE BUNDLES AFFECTED BY HORIZ STAB MOVEMENT. REPORTER STATED HIS CARRIER'S ENGINEERING HASN'T RESPONDED YET TO HIS REQUEST FOR BETTER WIRE BUNDLE POSITION DRAWINGS.

Data retrieved from NASA's ASRS site as of May 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.