EMB-145 Captain reported receiving fuel; oil; electrical; and gear system caution messages during cruise. After review with Maintenance and Dispatch; the flight crew continued to the destination airport; performed a manual gear extension; landed and taxied to the gate where passengers deplaned normally.

Narrative

As we were leveling off at FL290 we received an EICAS Caution 'FUEL CONFIG DISAG'; and lost the following indications; Fuel Flow E1; Oil Temp E1; Oil Pres E1; a number of the doors on the TO Page on the MFD and the GEN 1 and 3 voltage and load indications as well as the gear position indication and the roll trim position indications. I identified and canceled the EICAS message and asked the FO (First Officer) to take the radios which he did. I also informed him that it was most likely something Data Acquisition Unit (DAU) related but I didn't want to just press a DAU reversion button without direction from the QRH. For the 'FUEL CONFIG DISAG' the Message index gives no associated checklist and just says 'Crew Awareness'. As this did not give us a resolution to the missing indications I scanned the QRH for the next best option. Reviewed the Loss of engine indications checklist; which directed us to reset and alternate the FADEC on the affected engine however this did not resolve the situation; the checklist then directs an engine shutdown; however as this checklist was most likely not addressing the route cause of the issue and then engine was operating well with all other indications in the green I decided that at a minimum I would want to speak to Maintenance before shutting down a good engine but ideally find a more appropriate procedure.At this point it was time to start expanding the team; I voiced my opinion to the FO and he was in agreement. I was going to contact Maintenance on AIRINC (as our ACARS had frozen); but before I did I decided to check on the flight attendant in case there was something obvious in the back of the aircraft that might have been the cause; and also as our door indications were not valid. She said that everything was normal in the back; so I informed her that we were trouble shooting an issue and to contact us if there was any emergency but we were otherwise going essentially sterile for a little while. Whilst speaking with the FA (Flight Attendant) I was bringing up the Press to Talk procedure in the GOM; I then proceeded to dial Dispatch on AIRINC; and then got a reply from ZZZ radio that they'd prefer to just do a regular phone patch which they then initiated. Once on the radio with Dispatch they put me through to Maintenance; however we transitioned from the XXX.X to XXX.Y AIRNC sector around this time; lost coms briefly before re-establishing coms on XXX.Y. Maintenance Verified we had reset and alternated the FADEC and then advised us that we should just proceed to ZZZ1 which we were in agreement with. After terminating the phone patch I took the radios again and started preparing for the descent getting the weather from the ATIS; and calculating landing speeds and distances from the TLR. We were then stepped down to FL260 During the descent we transferred controls and the FO Briefed the approach; During the briefing it was apparent that we were not likely to get a gear down indication. The FO Asked what we should do if that happens; so I put forward that I think we should try to get the gear down very early in anticipation of that and that if we don't get a gear down indication we would either go around or not commence the approach and run the QRH associated with a gear unsafe indication and that we would give the FA and report call and have the passenger in the brace position just as a precaution. I asked what he thought of that plan and he agreed that would be the best course of action given the information we had and the time we had available. Shortly after the brief ATC advised us that Dispatch was trying to get a hold of us on AIRINC; I attempted to contact them however the frequency was tied up with a Company flight. I left Airinc up on COM 2 in case Maintenance tried us but then took the opportunity to check in with the FA. I Advised her that for now operations were normal and we were showing 15 minutes to the runway but that we would try to lower the gear much earlier to give ustime if further trouble shooting was needed and that if the indication did not come good we would go around; that she'd probably notice that; and she could expect us to give her a report shortly after and that we'd probably have the passengers assume the brace position just as a precaution. Shortly after we were cleared for the approach and a fair distance out as we were already below 250 kts. so we decided to put the gear down; and sure enough the amber dashed landing gear indication remained amber and dashed. I then reached back into the QRH to try to find the most appropriate checklist; and the FO took the radios and asked for delaying vectors. I began running the Gear extension abnormal checklist which early on directs the use of the Gear Electrical Override which I could not access from the left hand seat so we transfer controls and the FO then attempted to select the Gear Electrical Override switch to door however there was some confusion due to the placard next to the switch saying 'Not Avail'; it was hard to see from the left hand seat so I could not offer insight into the issue however after a few seconds he seemed to identify the necessary action and was proceeding with the checklist. The procedure then continued to a manual gear extension; However as we were unable to ascertain if the gear was locked we then proceeded to the partial or gear up landing checklist; I remained the PF (Pilot Flying) and the FO completed the checklist. The Checklist calls for Squawking XXXX so at that time we elected to[request priority handling]; I advised ATC of POB and endurance they requested that we not squawk XXXX and instead keep the discreet code so we did; the QRH also calls for the activation of the ELT which; seeing as our location was known; we were under surveillance and there is a G Switch on the ELT I felt it best to leave it in the armed position. Whilst I was speaking with ATC and Flying the FO gave the FA her report. Due to gusty winds we had originally briefed flaps 22 and were set up for that the FO advised he was more comfortable and confident with a flaps 22 landing; and I agreed so we added the 5 kts. to the flaps 45 VREF.We then had a brief discussion over who should fly the approach the FO said he felt good and ready for the approach; I felt like his mental state was more prepared for the approach than mine. The FO then flew the approach to XXL keeping the autopilot coupled; till about 500 ft. Mid final I just reiterated the need for a gentle touchdown both on the mains but also the nose wheel. On final Tower advised us that it appeared to them that the gear was down but that nose gear was hard to tell with the aircrafts attitude. The Landing itself was smooth and normal; we brought the aircraft to a stop on the runway. ATC advised us that the emergency vehicles that had been rolled to meet us said that everything looked normal to them. We came to the agreement that it was safe to taxi off the runway so we taxed onto the parallel taxiway and stopped where I then called Dispatch and Maintenance Control to verify if they were OK for us to taxi back to the apron. I then advised the FA and made a PA to the effect that we would need to wait for Maintenance before we continued to the gate. They advised us that they wanted to install the landing gear pins before we resumed taxiing so we waited for them to be escorted to us; they then boarded via the service door and collected the pins and installed them. They then drove off giving us a thumbs up as they did. A City of ZZZ1 car then relayed the message that they were happy for us to taxi to the gate now. We then contacted Ground and were cleared to taxi to the gate. We were unable to light the APU however because the APU indication was dashed out now also and the test would not indicate. When we arrived at the gate we shut the aircraft down and deplaned however the GPU was unreliable and we lost power during deplaning; so we were on batteries for a bit; I monitored thebattery voltage which stayed steady at 22v and then without warning all the avionics died. So I ran the termination checklist and reportable event check list just as the last passengers were getting off the plane. The FO and I then had a quick debrief. I then completed the Maintenance write up and discussed the various problems with the Maintenance crew that were on hand at the gate. While I was aware the that the route cause was DAU related; there was no concise way to translate the missing indications on to a specific DAU channel. In retrospect I should have asked Maintenance if they were ok with me trying a different DAU whilst I had them on AIRINC. Unfortunately the distraction of trying to maintain contact with them meant this didn't come to me until later. I had it in my mind to take a quick look at the ASM as this often has a summary of possible indication problems in the various chapters but by this stage we had sufficiently dealt with that problem and I needed to allocate some time to preparing for the approach. Some additional info in the QRH might have helped us find a more relevant and effective procedure. 2) Frozen ACARS was a massive time waster. I would have both eased dealing with the system malfunction and preparing for the approach. I'm normally pretty intentional about resetting the avionics on the ground between sectors (as this tends to prevent ACARS freezing) however as we were delayed departing due to a late inbound flight. I was reluctant to reset an the avionics and add time to the setup. A company procedure or software fix would be useful here. 3) I'm aware that there were numerous minor deviations that were made from the QRH because of the fact that the QRH didn't perfectly match the scenario. I'm normally fairly apprehensive about deviating from checks. However most of the training throughout upgrade and initial and recurrent focusses on scenarios that closely match the QRH; and more emphasis perhaps could be given to 'weird' scenarios that don't match. 4) We departed with 500 lbs extra fuel; but this was only just enough really for the additional flying that was required whilst we ran the QRH I normally request 200 extra myself but when I saw the 500 extra on the release I was satisfied this would be enough. In future I will be more inclined to ask for 200 on top of extra for other purposes especially ATC routing purposes. I'm more than happy to discuss further if there is information not in this report that you are curious about.