Date: 201409
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked; Taxi
Aircraft component: Potable Water Storage; control; indication
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Time Pressure
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Logbook Entry; Human Factors; Aircraft; MEL
Primary problem: Human Factors

Narrative: During preflight of aircraft the crew found that all potable water components worked in the cabin.  I looked back through the logbook to find what and why the potable system had been written up and why it was MEL'd.  I found that the 'Electric Compressor' had been declared INOP; and had been deferred in accordance with MEL 38-XX-XX. According to the MEL; this component must be deactivated; and/or isolated.  I found no evidence that this had been done (e.g. a pulled and collared Circuit Breaker CB).  I called Maintenance Control to inquire.  They said they would send mechanics out to inspect.  Two mechanics arrived: the first to come to the flight deck did not seem to understand the situation when I described the uncertainty regarding this MEL.  The second mechanic seemed more knowledgeable and after hearing me explain my concern about this MEL; took the aircraft logbook into the jetbridge and then called Maintenance Control.  Shortly thereafter he returned to the flight deck; slid the logbook into its slot; and said that we were 'good.'  I asked for more info.  He said that Maintenance Control told him that a CB in the mid-avionics E-bay was pulled and collared.  I asked if he visually inspected this to ensure it was.  He responded; 'You want me to check it?'   I was surprised at his response; and told him that yes; he needed to check it himself to ensure this CB was pulled and collared. My concern was that for some unknown reason this electrical component; the 'Electric compressor'; was declared INOP (possibly because it posed a hazard to the aircraft); and therefore it needed to be deactivated; as required by the MEL; for the aircraft to be considered airworthy.  I needed this Mechanic to be certain this was accomplished.  He left the flight deck to check.  He came back very quickly (too quickly; I thought; to have gone down below; opened the e-bay hatch; inspected the CB; closed the hatch; and returned to the flight deck); and told both the First Officer and me that 'Yes'; the CB to the electric compressor was pulled and collared.  I thanked him and we soon departed the gate.  On pushback I continued to wonder: shouldn't we have some indication of a CB being 'tripped' in the cockpit?  Perhaps on the EICAS; or the Multipurpose Control Display Unit (MCDU)?  After completing the pushback; I called Maintenance Control on the phone.  Maintenance Control discussed the issue with me very patiently.  He explained that we cannot see the status of all the CB's from the cockpit.  I asked about the 'Water Compressor' remote CB that I could view via the MCDU; and whether or not this was for the 'electric compressor' written up.  After reviewing some documentation; he told me that it was not.  He told me that as he understood the system; the CB in question controlled a valve separating pneumatic pressure from engines and APU; and from the electric compressor.  He also explained that the mechanic who originally wrote up the problem would have used the maintenance manual to guide him through securing the faulty component.  At that point I felt I'd exhausted the issue and deferred to Maintenance Control's understanding of the status of this system.  We taxied to the runway and took off for ZZZ1.As we flew to ZZZ1; I continued to ponder the situation.  The information I gleaned from reading the relevant sections of the AOM Volume II seemed to contradict what I had been told by Maintenance Control and the individual mechanic in ZZZ regarding the system and associated CBs.  Upon landing in ZZZ1; I called Maintenance Control again; and explained my concerns and requested a mechanic come out to the aircraft and show me in the mid avionics E-bay the CB that had been pulled and collared for this MEL.  When the mechanic showed up; the first thing he did was look at the CB menu in the MCDU in the cockpit to see if any CBs showed 'out' [pulled] for this system.  I told him I wanted to look in the E-bay.  We went down below the aircraft; opened the E-bay hatch; and he inspected the CBs inside.  He told me that NO CBs were pulled; but all were in.  I looked inside myself; to confirm with my own eyes.  I was disappointed that my suspicions were correct: no CB had been pulled and collared in accordance with the MEL.  Even worse; this was incontrovertible proof that the mechanic in ZZZ actually LIED to me regarding a CB being pulled and collared in the E-bay; and in general; as to the status of the aircraft. At this point; I entered into the aircraft logbook the entry  'Request inspection of the potable water system to verify MEL 38-XX-XX complied with.'  The mechanic in ZZZ1; in coordination with Maintenance Control; via the MCDU; pulled out and locked the remote CB for the Water Compressor (the same one I'd asked about in ZZZ); and signed-off the aircraft in the logbook.  We soon departed on our next flight.First; anything that is an 'MELable' item should have a very clear; precise checklist that Maintenance utilizes to ensure that the faulty component is properly secured.  Then later; if asked by a concerned PIC to verify an MEL is properly complied with; this resource could be used as a quick reference to remove any doubt as to whether or not proper actions have been accomplished.  Throughout the experience described above; there was much ambiguity and several contradictions from the several Maintenance representatives as to their explanations of the system and associated MEL procedure; all seeming to come from their individual memories as to how the particular system worked.  Further; the ever-present time pressure to stay on schedule was urging all parties to find any excuse to dispatch the flight onward.  Second: the actions and statements of each of our employees must be guarded and directed by an overall sense of INTEGRITY; so that each person in the operation can trust one another.  Lying must not be tolerated.  Whatever objectives an individual has for lying about the status of an aircraft; whether to please a superior by getting a flight out quickly; or to cover up for a mistake made; etc.; these contravene the priorities and values of our airline; and are an attack on the safety culture of our airline.




Synopsis: Pilot of an ERJ-170 aircraft explains the importance for maintenance to have a clear; precise checklist when deferring any MEL item; in order to ensure a faulty component is properly secured and the aircraft is in fact airworthy. He added that employees must have a sense of integrity and that lying to flight crews not be tolerated. Mechanic told Captain that he had verified a Water Compressor C/B had been pulled and collared; but was later found not pulled.