EMB-145 flight crew reported multiple navigational system malfunctions during climb resulted in return to departure airport.
Synopsis
EMB-145 flight crew reported multiple navigational system malfunctions during climb resulted in return to departure airport.
Narrative
During climbout on the ZZZZZ SID; I was serving as PF and LCA (Line Check Airman). Just prior to 17000'; PFD1; MFD2; and FMS1 went black. My FO and I immediately started troubleshooting the problem. I chose to select reversion mode on my side to PFD (Primary Flight Display). That allowed my PFD to once again work; but the data was not showing correct information - it was completely different from my FO had displayed. ZZZ Center asked if we were on a heading; as our course was now off due to my FD following stale (later realized to likely be frozen in time from the last good data sent by FMS1 to the PFD) heading information. I told them we were not on an assigned heading; but were having an avionics issue and were trying to work out the issue. I transferred controls to my FO and coupled to his side; as his PFD was showing true information. ATC then gave us a heading and had us level off at 17000' to try to resolve the issue. The FO noticed that the Avionics 1 Master was now lit up and popped out. I thought perhaps it had been pushed out; but wasn't clear on how; as neither of us had touched it. I pushed it back in to try to resolves the situation. FMS1 came back on with the message Single Operation. I tried to get the FMS working again; but the screen now had a rainbow pattern across the top row and a gibberish of alphanumeric characters on it and was inoperable. My FO and I continued to assess the problem; referring to the avionics section of the QRH; though what we were presented did not match any malfunctions we had ever seen; in the sim or otherwise; perfectly. We ultimately determined it could be a signal generator issue; but the fact that the Avionics Master 1 had popped out on its own also concerned me as I thought we were perhaps dealing with a larger electrical issue. PFD1 displayed completely different course and heading information from PFD2. I selected SG reversionary mode on my side; allowing me to see my FOs correct information on my PDF instead of my frozen; incorrect; data. I advised ATC and asked for vectors back to ZZZ to land. Initially we were being vectored to land on XXR. I called our FA and passed on the safety briefing and told him to prepare for a normal landing. He reported back a few minutes later that the cabin was ready. I also made an announcement to passengers that we were returning to ZZZ due to an avionics malfunction and that we would keep them informed. I built the approach in my FOs FMS and got it set up. ATC offered us XXL and I decided to accept it as that would give us PAPIs in case we lost my FOs FMS as well as mine. I built the XXL ILS approache and briefed my FO on it. My FO asked about landing weight - we were going to be slightly overweight based on the performance landing data. We asked for delaying vectors to finish our preparations for the approach; allowing me to obtain appropriate speeds; answer questions from dispatch and ATC as well as to burn some fuel and get closer to an appropriate landing weight. We did run the overweight landing QRH just in case we had to land overweight; but we ultimately were able to burn enough fuel through delaying vectors and by configuring early. ATC informed us while on short final that emergency vehicles would be waiting alongside the runway and we were asked if we needed any assistance - I told them no. My FO landed without incident. We taxied in on our own power to the gate with emergency vehicles trailing us and in communication with us. After we opened the MCD (Main Cabin Door); I faced the passengers in the cabin and spoke to them over the PA telling them what we had done and why. The passengers were pleased with the decision and we told them we'd let the know how they would be getting to City X and had them deboard. Maintenance met us and I made the appropriate write ups and called maintenance control. Suggestions: The only thing I would have done differently would be to advise ATC earlier. I have had transient PFD interruptions in the past and thought it was a similar event; but this was quite different than any avionics issue I have observed either in training or on the flight line.
Second reporter narrative
Captain and I operated this flight from ZZZ to ZZZ1. This was supposed to be my last IOE trip and Captain was my Line Check Airman. I was the PM and she was the PF. During our climb; I heard an electrical popping noise followed by PFD 1; MFD 2 and FMS 1 went completely dark shortly before passing 17;000ft. While we were troubleshooting; ATC asked if we were on heading mode since we were not directing to the fix assigned. We told them we were having Avionic issue and would need to stop climbing to trouble shoot. They told us to level off at 17;000ft. After leveling off; Captain suggested to check if any circuit breakers popped out after transferring control to me but none did. We then noticed the Avionic 1 master switch was in off position so Captain pushed it in and got our screens turning back on. However; FMS 1 and 2 were in Single Operation mode and our PFDs (Primary Flight Display); MFDs (Mulit-function Flight Display) were showing different information. As we tried to put both FMS in dual mode; FMS 1 went into this weird colorful screen with random letter. We went through the QRH but didn't find any section with information pertaining to our situation. At this time; Captain decided to return to ZZZ. We ran overweight landing QRH but ended up requesting delayed vector so we would have more time to set up for the approach and burn all the extra fuel. We also advised ATC as we didn't know if there would be more electrical related issues arising. We landed the airplane and taxied back to our gate safely. Captain did an amazing job communicating with ATC; dispatcher; FA; and passengers while troubleshooting and preparing for our return to ZZZ.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.