Date: 201602
Local time of day: 0601-1200
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Speed (Rate Sensing)
Reporter organization: Contracted Service
Reporter function: Technician
Human factors: Communication Breakdown; Confusion
Anomaly: Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Aircraft In Service At Gate
Contributing factors: MEL; Procedure
Primary problem: MEL

Narrative: An Aircraft arrived with a logbook item 'MIN MANEUVER SPEED AMBER BAND DOES NOT DISPLAY AT CRUISE ON FO SIDE. CAPT SIDE OPERATES NORMAL'. After some discussion with Maintenance Controller it was decided to use MEL. I completed SP1; SP1A and SP2; Aircraft was downgraded to CAT I status. Additional placards were installed per SP1 for associated systems considered inoperative. Past practice and interpretation has been to install these additional placards as described in the instructions of the MEL; and as read back by the maintenance controller when receiving the MEL who gives a tracking number that is currently being applied. Upon further discussion between the Flight Crew; Dispatch and maintenance; One interpretation of the MEL [was] that when a system is considered inoperative all associated MEL special procedures and tests must be complied with. At the time; some other Maintenance Controllers did not agree with this interpretation but agreed with the past practice. Further discussion ensued and explained that this view was based on the MEL Policy Section; which states; 'The phrase 'Considered Inoperative' as used in the provisos means that an instrument and equipment item must be treated for Dispatch; taxi and flight purposes as though it were inoperative. The item will not be used or operated until the original deferred item is repaired. Additional actions include: documenting the item on the Dispatch release (if applicable); placarding and complying with all remarks; exceptions; and related MEL provisions; including any (M) and (O) procedures and observing the repair category.' More discussions followed with Maintenance and Dispatch Team Lead and it was agreed that his opinion made sense as we all read the definitions section of the MEL. Following that train of procedures leads a Technician to go from the base MEL to - in this case - six other related MELs. This leads to numerous opportunities for procedures to be missed as we are forced to switch between MELs; SPs and Maintenance Manual (MM) references. The Flight Crew is also confused when they have an MEL for a system that specifically calls for two circuit breakers to be opened and collared. Upon their inspection of the circuit breaker panels; they find three; four or five additional circuit breakers collared which are related to the 'considered inoperative' systems. The Crew is left to guess that they must be part of the MEL for the original system. This opens the door for additional errors because the Crew can no longer act as a cross check or second set of eyes on the collared breakers. The Aviation Maintenance Technician's (AMTs) instruction to open the breakers is found in the MM which the Crew never gets a look at in their [computer]; EFB or their release.




Synopsis: A B737-800 Maintenance Technician reported an MEL is confusing when relating to 'MINIUM MANEUVER SPEED' Indication.