Date: 201901
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Pax Seat
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Confusion; Training / Qualification
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Maintenance Action
Contributing factors: Human Factors; MEL; Manuals; Procedure
Primary problem: MEL

Narrative: During preflight; I was reviewing the MELs which were both applied to a seat. On the sticker located in the cockpit; the description was labeled 'Seat X INOP'. In the Summary of deferred items sheet; the MEL (Minimum Equipment List) 'Description of item deferred' said 'Seat X Inop'. There was also a 'DO NOT OCCUPY' placard on seat. After reviewing the MEL in our manual; it appeared to me that the seat could be occupied. However; I was very concerned with the fact that we had three cues clearly indicating the seat was inoperative and should not be occupied (the sticker; the summary of deferred items sheet; and the DO NOT OCCUPY placard). The write up 'action taken' column also described 'Deferred Seat X IAW (In Accordance With)...' for the write up 'Seat X; Arm Rest Broken'. I called Dispatch and Maintenance Control. Maintenance Control reviewed the MEL with me and believed that the seat could be occupied as well. I questioned why we had so many things pointing at the seat not being occupied. He was not sure but told me to just remove the DO NOT OCCUPY placard. I hung up but called back one minute later and told him I would be more comfortable with Maintenance doing this task. I additionally wanted them to take a look at the armrest/logbook to ensure that everything was legal and safe. Maintenance was on board the aircraft. He reviewed the MEL and wasn't sure if the seat could be occupied or not. He called his supervisor. It was at this point I realized that there seemed to be some confusion with this MEL so I asked to talk to the on-duty chief pilot. [He] told me that the FARs required that armrests be down for takeoff and landing; so since this one was missing; we should defer the entire seat. Maintenance Control disagreed with this and said this was a proper deferral. The Maintenance Supervisor then arrived and also reviewed the seat and MEL. He found conflicting information in the manual. Under Maintenance (M); the MEL seems to suggest a complete seat deferral if the aisle armrest is 'inoperative' and unable to be secured upright or placed in the fully down position. He interpreted 'inoperative' to be the same as missing or removed (as was the armrest). In the end; [he] contacted multiple people including [Maintenance Control]; chief pilots; manager of compliance; etc. It was determined that MEL was the proper and legal MEL and that the seat could be occupied. However; the aircraft was not full so no-one occupied the seat regardless. From a flight ops standpoint for me; the primary source of confusion was the fact we had so many things pointing at a complete seat deferral even though the MEL still technically allows the seat to be occupied. There seemed to be a lot of confusion between different departments and we had a lot of people involved in sorting through this issue. I wanted to ensure everything was legal and safe before departing. I think that MX (Maintenance) could have done a better job with deferring this armrest which was the root cause of the confusion. It looked as if they had deferred the seat. I also think our manual could be more descriptive for maintenance. Is an aisle or middle armrest 'inoperative' if it is removed? I believe you can't 'operate' an armrest if it isn't there; which would have led me to believe both the aisle and window seat should be deferred completely.




Synopsis: EMB-175 Captain reported confusion with the deferral of a passenger seat due to missing armrest. After contacting Maintenance the deferral was changed to allow the seat to be occupied.