Date: 201910
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Cockpit/Cabin Communication
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Troubleshooting; Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural FAR; 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: Human Factors; Logbook Entry; MEL; Manuals; Procedure; Aircraft
Primary problem: MEL

Narrative: We received an aircraft about 45 minutes prior to departure for our flight with multiple MELs: tail boom nav light; window reveal assembly; windshield wipers; and the associated CAT II downgrade. During preflight review of the paperwork and logbook; I noticed that the MEL we had for the windshield wipers was inconsistent with the write-up. Though the windshield wipers were MELed in the aircraft logbook; the discrepancy complained of repeated Number 1 windshield HEAT failures. I pointed this out to the Captain and we contacted Maintenance Control and Dispatch. Maintenance Control sent local Maintenance to the gate to correct the logbook and Dispatch worked on amending the paperwork. We began boarding.As we waited for Maintenance we continued our preflight. When the Captain performed the stall protection system test; we both immediately noticed that the stall warning and caution warning bells were very distorted on the Captain's speaker. I pressed the takeoff configuration check to trigger more aural warnings with the same result; nothing but static from the speaker. The Captain selected speaker audio on the Digital Audio Panel and we could hear the radios just fine through the Captain speaker; confirming that there was only a problem with aural warning tones on the Captain side. The warnings were audible in the cockpit through the First Officer speaker. The Captain checked their headset and noted the same problem in the headset: radios and interphone were fine; but aural warnings only produced static. When local Maintenance arrived we notified them of this newly discovered problem. One mechanic took the logbook to work on correcting the windshield heat MEL in the jetbridge; and the other asked the Captain to step out of the flight deck so they could gain access to troubleshoot. The Captain stepped onto the jetbridge while I remained in the cockpit. First the mechanic checked the AWU (Aural Warning Unit) channels; and both were good; both channels worked on the First Officer side; but only static was audible on the Captain side. The Mechanic removed the Captain's headphone panel to check for loose wires but couldn't find any. At this point; the mechanic said they didn't really know what to do; and they'd have to check with Maintenance Control about an MEL. Problem was; there really wasn't an MEL for this specific issue-- the AWU channels were fine; and the Captain's speaker was fine. The problem was probably some input to the audio panel; but Maintenance couldn't figure it out there at the gate. The Captain returned to the cockpit and I briefed them on what Maintenance had done and said. We discussed the fact that the warnings were still perfectly audible in the cockpit through the First Officer's speaker. Local Maintenance returned with the logbook. They had corrected the windshield heat MEL and said 'we're just gonna MEL the Captain speaker.' As they had been on the phone with Maintenance Control in the jetbridge; we assumed; and they made it seem like this had been the judgement of Maintenance Control. Their writeup was 'CA SPEAKER MUFFLED.' This immediately struck me as odd; since that wasn't really the problem. We looked up the MEL and found that either speaker was Mel-able as long as the headphones worked normally on that side. This seemed questionable to me-- 'normal' operation of the headphones wasn't really defined; and they did work normally; except that the aural warnings sounded like static. The Captain and I discussed this; and Maintenance had convinced the Captain that this was the best MEL they could do to get us on our way and the plane to a place where it could be fixed downline. Somehow; this managed to convince me too. For some reason; after dealing with all the other paperwork and incorrect MELs on top of the time pressure; the plane managed to seem acceptable to us because the Captain could hear aural warnings without issue with their headset on (though the warnings they heard were only from the First Officer speaker). We closed the main cabin door and completed our checklists; but decided we'd wait at the gate until the speaker MEL was added to the paperwork. The Captain messaged Dispatch about adding the MEL; and Dispatch responded saying that we needed to call Maintenance Control. Fortunately; the Maintenance Controller did not find that MEL acceptable. The Controller was very upset-- he told us that he had not authorized local Maintenance to sign off that MEL and he would not release the plane with that MEL; since it was not correct for the discrepancy. In fact; there was no MEL for our discrepancy; and therefore; the plane was not airworthy. At that point; I realized we had just done something wrong-- and I was very surprised it took us up to that point to realize it. We deplaned. Local Maintenance returned and added a new logbook entry correcting the 'CA SPEAKER MUFFLED' entry to 'Aural warnings not audible on Captain speaker or headphone.' We received another aircraft and completed the flight without further issue.Multiple MELs; incorrect MEL; time pressure; new discrepancy on top of correcting another MEL. One of the mechanics who arrived to correct the windshield heat write-up had been the one who had added the incorrect windshield wiper MEL; therefore; they seemed like they were under a lot of stress to get that corrected without causing us a delay. I think that stress may have bled into them trying to get the aural warning discrepancy resolved as quickly as possible. It was also our third flight of the day; so we were likely victim to some last leg get-there-itis. Accepting the logbook with a writeup that didn't cover our discrepancy was an error. Thankfully we waited at the gate for the release amendment; which trapped our error and prevented a [policy deviation].I think somehow I managed to forget the fact that the MEL does not cover anything. If it's not in the MEL; it's not deferrable. In this instance; I let time pressure and Maintenance convince me that an MEL that covered part of the problem was 'good enough.' This really goes against my personal standards-- I generally question everything and I don't hesitate to speak up if I think something is incorrect; but I failed to listen to my gut tell me in this instance that what the mechanics were doing was not right. I think that voice was drowned out by everything else going on. And perhaps something else-- perhaps a little complacency as well. I will be sure not to take the Mechanic's word that we're 'good to go' again; as I hadn't in the past-- if I have any doubts; I'll insist on verifying that we're doing the correct thing with whoever we need to do that with; be it Maintenance Control or a Chief Pilot. I'm certain the Captain would have done that if I had said I was uncomfortable with the MEL.




Synopsis: EMB-145 First Officer reported incorrect logbook entry and time pressure caused Maintenance Personnel to attempt to apply an incorrect MEL; resulting in a flight delay.