CRJ700 flight crew reported malfunction with Lamp Driver Unit affecting cockpit switch lights; resulting in a diverted and uneventful landing.
Synopsis
CRJ700 flight crew reported malfunction with Lamp Driver Unit affecting cockpit switch lights; resulting in a diverted and uneventful landing.
Narrative
This was my X [number] flight after completing IOE. First flight of the day. ZZZ1-ZZZ2. Preflight; ground ops; takeoff; and departure were all unremarkable. While climbing from FL330 to FL350; numerous lights illuminated for roughly 5 seconds. The light my eyes noticed first was the RH ENG FIRE PUSH light. The lights extinguished and we both checked out the EICAS display for messages. There were no messages. We checked out every possible system/synoptic page; and looked for any non-normal indication. The aircraft by all appearances was perfectly healthy. We had a conversation about possible causes and possible courses of action. During our conversation several lights came back on but this time persisted. In no particular order; the lights that illuminated were as follows: STALL; COPILOT ROLL; PILOT ROLL; EMER DEPRESS ON; RH ENG FIRE PUSH; APU SOV FAIL; LH AIR CON PACK OFF; GND PROX; RH BOTTLE ARM; RTU 1 Inhibit; Master Caution; Master Warning. It's possible that other lights flickered on and off as well; those were the ones that I had time to write down. No audio was associated with any of the lights and once again; with no EICAS message to confirm an actual malfunction was occurring. We rechecked all synoptic pages again and the plane's systems were all still functioning normally. The Captain gave me control of the aircraft and he started to troubleshoot with the QRH. There were no messages on our EICAS so he checked the non-messages section. Nothing we were experiencing was in the QRH. The Captain and I deduced that it must be some sort of LDU (Lamp Driver Unit) or DCU (Data Control Unit) malfunction. A conversation was had about what would happen if a real-world system malfunction was to occur; would be get an indication? We were operating in a gray area not covered by the extensive QRH. The erroneous lights could create confusion for the execution of a legitimate QRC/QRH procedure. We knew we needed to get on the ground. The Captain took the aircraft back and I pointed out that ZZZ was at our 12 o'clock in 100 NM. We [requested priority handling]; and began our preparation to land in ZZZ. We kept everything normal. While I had the bandwidth; I quickly wrote down all of the lights we were seeing. We landed in ZZZ uneventfully. We swapped out the failed component (LDU) and flew the passengers to ZZZ2. We also flew one more leg after that to end the day.
Second reporter narrative
While climbing from FL330 to FL350 in cruise flight approximately 30 minutes after departing ZZZ1 enroute to ZZZ2; I noticed the PLT (Pilot) ROLL switchlight illuminate for about five seconds then extinguish. My FO informed me that something on his side momentarily lit up too. We then scanned our panels and checked all synoptic pages and determined all systems were functioning normally and no further switchlights were illuminated. We elected to continue assuming it was most likely an insignificant electrical anomaly that I would write up when we arrived at ZZZ2. After a few minutes of uneventful flight; we noticed several switchlights illuminate and continued to persist. The most concerning of which were the left side STALL; RH ENG FIRE PUSH; right side STALL; PLT ROLL; left pack OFF; APU SOV FAIL; EMER DEPRESS ON; and left and ride side MASTER WARNING. These lights were not associated with any EICAS messages. I quicky rechecked all synoptic pages and all systems were still functioning normally. I then cycled lamp test 1 and 2 multiple times in an attempt to extinguish the seemingly erroneous switchlights; but the lights stayed on. Considering there were no EICAS messages; and the systems were functioning normally; I determined that it was most likely a DCU (Data Control Unit) or LDU (Lamp Driver Unit) malfunction. I gave my FO the controls and ran the QRH. I checked in the non-messages section of the QRH but found no checklist pertaining to our situation. We were concerned that if there was a system malfunction later in the flight; the erroneous switchlights would certainly cause a distraction and perhaps cause confusion while running a QRC/QRH checklist. We determined that the safest course of action would be to divert and get the problem resolved before continuing the lengthily flight to ZZZ2. Luckily ZZZ was immediately off our nose and approximately 100 nautical miles away. We decided ZZZ was the ideal diversion airport considering it is a company maintenance base; and the weather was VFR. I took back the controls and comms and advised ATC that we needed to divert to ZZZ and [requested priority handling]. During this time my FO cleverly wrote down all of the switchlights that were illuminated so that we would have an accurate list of discrepancies to give to maintenance. We arrived in ZZZ shortly after where Maintenance met us at the gate. The maintenance personnel found that it was in fact an LDU fault and replaced the proper component. After completion of the maintenance; we operated the same aircraft to ZZZ2 without any further issues.Suggestion: Incorporate a lamp test into my own personal acceptance flow.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.