Date: 201203
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Night
Aircraft: B737-400
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Electrical Wiring & Connectors
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Workload; Training / Qualification; Time Pressure; Situational Awareness; Distraction; Confusion; Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Aircraft In Service At Gate
Result: General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Company Policy; Human Factors; Incorrect / Not Installed / Unavailable Part; Procedure; Chart Or Publication; Aircraft
Primary problem: Human Factors

Narrative: On Midnight shift March 2012; I was assigned to Aircraft X; a B737-400 Overnight Check with ACARS MEL; two nose tire replacements and a Maintenance Control Service Item [electrical] bussing plug replacement. While working aircraft and trying to find bussing plug; Lead Mechanic requested Engineering Order (EO) be issued to aircraft to do typical temporary [bussing plug] repair and defer final repair to next C-Check because of extended down time for final repair. While Engineering Order was given to Lead; I found no part in ZZZ and part [was] scheduled to arrive on final midnight flight [from] ZZZ1; [but] was not onboard; had to defer Service Item because no [plug] part available. Maintenance Control Service Item [bussing plug] was not time restricted. Continued work on aircraft and deferred [Service] Item through [Maintenance] Planning; [but] unaware that Engineering Order (EO) XXX26  [issued to lead Mechanic] was restricted; to be done before further flight. On following night I was assigned Aircraft X again; with an Overnight Check; Takeoff Warning Check and same Maintenance Control Service Item [bussing plug replacement] again.  Because of numerous check items that required attention: two main tire changes; an overserviced A-System Hydraulics; an under-serviced B-System hydraulics; navigation light out; cabin item inbound and many screws missing on engine pylons; the Overnight Check was not completed until XA:30am; not leaving enough time to complete the Maintenance Control Service Item; but [did] finish Take-off Warning Check at [same time] XA:30am. Had to complete paper work half hour later; with departure one hour later.   Lead Mechanic was notified by [Maintenance] Planning; Mr. X; that a Repetitive Deferral was not placed on the aircraft and wanted more information as to why the [Service] Item was deferred without complying with the Manufacturer's Service Letter and Repetitive Check deferral [requirements] for the Maintenance Control Service Item that was issued. Engineering Order (EO) was issued before parts were available; since we were not going to accomplish the Service Item; we did not review the time restriction. When reviewing previous history from other aircraft with similar EO's issued; it has been determined that an EO should have been created to address this issue with sufficient time limitations to accomplish the task. Aircraft was removed from service in ZZZ1 to perform Engineering Order # XXX26; this aircraft flew for two days without the EO being complied with (nine legs). The Maintenance Control Service Item was accomplished on the Overnight Check that night and the EO was complied with; reference Logbook pages Suggest do not request any EO until parts are available and you are ready to accomplish job. Also if Maintenance Control Service item is not time sensitive; do not issue a restrictive EO for an airworthiness aircraft before the Maintenance Control Service Item drop dead [date]. Maintenance Planning found error.




Synopsis: A Line Mechanic reports an Engineering Order (EO) with time restrictions was issued on a B737-400 aircraft for temporary repair of a bussing plug requiring accomplishment prior to flight that conflicted with a Maintenance Control Service Item replacement of the same bussing plug that was eventually deferred without time restrictions.