Date: 201402
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Troubleshooting; Confusion
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: Pre-flight
Result: General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: During our preflight activities I noticed a strange annunciator illuminated that was just a straight line. I brought this to the Captain's attention and we began to investigate what it could be indicating. We referenced the AOM annunciator chart which indicated that it should be an ice FOD annunciator however those annunciators were elsewhere on the panel. Not being able to determine the cause; we called ops to have them alert maintenance. Two mechanics arrived later at the flight deck door and we pointed out the annunciator in question. I do not know their names. Their immediate response was something to the effect of ...now is not the time for this...you need to just go. This may not be a direct quote; but I was so taken aback by the mechanics response; that I immediately wrote it on my notepad on the yoke. The reaction of the mechanic immediately created a negative atmosphere as it appeared they had no interest in determining the cause of the annunciator and were applying pressure to 'just go.' I asked them what is causing the annunciation to which they responded that they didn't know and that there were lots of annunciators illuminated on the panel. I explained that when we are departing there are only a few annunciators that should be on and that a horizontal line is not one of them. The situation was eventually defused when the Captain stated that he would or had 'put it in the book.' After sometime; another mechanic appeared and stated that they would look into the issue. After conferring with maintenance control it was determined that the light was the deactivated rain repellant system. We did ask why the light was on if the system was deactivated. He didn't know the answer; but in conferring with maintenance control was comfortable signing off the write up. We then departed. The Captain and I later noticed on the way back that there was tape residue on the annunciator as if it had been previously placarded or taped over. We became less comfortable with the previous sign off and upon landing the Captain made another entry in the logbook regarding the annunciator. Some time later I talked to that mechanic who said that it had been determined that the annunciator was actually an AHARS[?] basic annunciator and an incorrect indication (yellow line) was on the annunciator panel. I have since also learned that the pilots of a 'sister ship' were called and asked what annunciator was on that plane where ours had a line. I believe that is how the problem was finally solved. It appears that this aircraft has flown around in an incorrect configuration for sometime. Safety concerns: The response of the initial mechanics which was that although they didn't know what was causing the annunciator that we should just go. The information in our AOM is incorrect and was of no assistance in diagnosing the issue. How was the incorrect diagnosis of a rain repellant annunciator made? The tape residue on the indication would seem to point to this having been an issue in the past. How long has this airplane been flying in an incorrect configuration on the annunciator panel? In conclusion; I would like to commend the attentive mechanic for his professionalism. When he initially came to the cockpit; he looked at the indication and stated that they would look into the issue. When he returned; he calmly explained what they believed the issue was and why he signed it off; allowing us to be comfortable that he had thoroughly diagnosed the issue and was comfortable signing off the discrepancy.




Synopsis: An MD-80 First Officer expressed concern when maintenance technicians failed to take seriously the existence of an unexplained annunciator prior to departure; instead suggesting they just fly the trip.