Date: 201310
Local time of day: 0601-1200
Location: ZZZZ.Airport, FO
Light: Daylight
Aircraft: B757-200
Operator: Air Carrier
Operating under: Part 121
Mission: Cargo / Freight / Delivery
Flight phase: Parked
Aircraft component: Stall Warning System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Other / Unknown
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Confusion; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Aircraft; Human Factors; Manuals; MEL
Primary problem: MEL

Narrative: Maintenance in ZZZZ found the Cannon plug broken on the First Officer's Stick Shaker. We applied MEL 27-32-02 which has you pull and collar the Circuit Breaker for the affected system isolating the Stick Shaker motor. The Cannon plug was secured and capped per the Aircraft Maintenance Manual (AMM) Chapter-20; since it could not be re-connected to the broken receptacle on the motor. Initially; an Engineering Authorization was pursued until we realized that we could deactivate the system by pulling and collaring the Circuit Breaker per the MEL and that would isolate the broken connector. At that point; with Engineering Management's concurrence; we did not pursue an Engineering Authorization. The system was deactivated by pulling and collaring the Circuit Breaker for the Stick Shaker per the MEL.  The Cannon plug on the motor was broken; it was not removed for isolation of the motor; and it could not be connected to the receptacle on the motor.  I felt that the intent of the MEL was met and that we were not further isolating the system with the broken Cannon plug being disconnected as the maintenance alert states. [Recommend] clarifying the intent of maintenance alert XX-000. What is the exact communication from the FAA on this?   When an item of equipment is inoperative (Stick Shaker motor Cannon plug Circuit Breaker) and maintenance is deferred under the guidance of the MEL (pull and collar Circuit Breaker); the airplane must be operated under all applicable conditions and limitations contained in the MEL: (pull and collar Circuit Breaker).  Until further notice; if an additional isolation procedure is deemed to be necessary at any time during the deferral period of an MEL item; contact Maintenance Control and submit an Engineering Request. Engineering may issue an Engineering Authorization on a case by case basis to permit these procedures if appropriate.  If Engineering does not issue an Engineering Authorization; or the conditions of the MEL cannot be met; the item must be repaired prior to further flight. Additional isolation needs to be defined. This was a broken Cannon plug on the Stick Shaker motor. Is this an additional isolation; or an inoperative system addressed by the MEL?  Aircraft Maintenance Manager.




Synopsis: An Aircraft Maintenance Manager reports about the need for clarification of a company Maintenance Alert that describes the importance of requesting an Engineering Authorization (E/A) when an additional isolation procedure is applied during a deferral process. Cannon plug for the first officer's Stick Shaker motor was broken and was capped-off; but was not part of the MEL procedure for deferral of the Stick Shaker System on a B757-200.