Date: 201812
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Thunderstorm; Turbulence
Light: Night
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Air Data Computer
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Fatigue; Workload; Distraction
Anomaly: Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Landed in Emergency Condition; Flight Crew Diverted; General Maintenance Action
Contributing factors: Company Policy; Human Factors; Weather; Aircraft
Primary problem: Human Factors

Narrative: I was scheduled to fly Aircraft X from ZZZ to ZZZ1. There were storms in the ZZZ1 area; which we were aware of prior to leaving ZZZ. I was PM (Pilot Monitoring); and the Captain was PF (Pilot Flying). The majority of the flight was uneventful until we were approximately 200 nm NE of ZZZ1. Around that time; we were given holding instructions at [an intersection] on the [Arrival.] When arriving at [the intersection]; ATC assigned us a different hold; this time at ZZZZZ1 at FL340 and advised us that both ZZZ1 and [another nearby airport] were closed 'indefinitely.' We let dispatch know; entered the new hold; and continued with our fuel calculations to determine when we would divert to our alternate. Dispatch had assigned us [two other possible airports] as alternates. We would have needed to divert immediately if we wanted to go to [one of the alternates]; so we messaged dispatch to let them know we were considering [the other alternate]. We had enough fuel to hold for approximately 30 minutes; which coincided with our EFC (Expect Further Clearance) time. After a few messages back and forth with our dispatcher; he suggested that instead of [the aforementioned alternate]; we consider ZZZ2. ZZZ2 is a little bit closer to [the intersection we were holding at]; which meant we could hold a little bit longer; so we told Dispatch that we would divert to ZZZ2 if necessary; but that we'd continue in the hold until our EFC time.Shortly after making this decision; we got an EFIS (Electronic Flight Instrument System) COMP MON caution message and an IAS (Indicated Airspeed) flag on our PFDs (Primary Flight Display). [The Captain] called for the QRH (Quick Reference Handbook) checklist; which I started to run. We also asked for a descent from ATC. While I was running the checklist; we got caution messages for MACH TRIM (it had disconnected); RUD LIM FAULT; and STALL FAIL. Our flight directors also starting giving us wildly erroneous suggestions; so [the Captain] turned them and the autopilot off and hand flew using raw data. He also attempted to reengage the Mach trim; but it immediately disengaged again. During this entire time; we were in night hard IMC; moderate turbulence; and lightning/St. Elmo's Fire. We were also showing very different airspeeds on PFD1 and PFD2 and were uncertain which was correct. I remember glancing at the ISI (Integrated Standby Instrument) during this time; but I don't remember whether the indicated airspeed on the ISI was similar to either PFD1 or PFD2. I [coordinated] with ATC and told them that we needed to divert to ZZZ2.The QRH checklist for EFIS COMP MON IAS failure directs you to 'select reliable side' on the Air Data source selector. At first; we were uncertain which side was reliable. The airspeed on my side (PFD2) was 0.69M; while the airspeed on [the Captain's] side (PFD1) was 0.65M. However my airspeed started to quickly drop off and was clearly not matching that of the ISI. We decided that it was ADC2 (Air Data Computer) that failed. However; even once switching everything to ADC1; the caution messages remained and we were uncertain that the airspeed indications were correct. At this point we wondered whether we had selected the wrong ADC and decided to select ADC2. When we did this; we got red Xs on all of our instruments. We quickly switched back to ADC1 and proceeded on the theory that ADC2 was the problem. We were still concerned about our indicated airspeed and used ground speed reports from ATC to back up what we were seeing on the flight deck.The EFIS COMP MON IAS checklist then directs you to the 'Air Data Computer Failure' checklist in the QRH. I ran this checklist as well; which states that R FADEC FAULT 2; SPLR/STAB FAULT; AND RUD LIMIT FAULT status messages will come on. It does not say anything about the STALL FAIL status message or the disconnection of Mach trim. Because the RUD LIM FAULT appeared to be associated; I moved on to the QRH checklist for STALL FAIL. I was also talking to ATC; manipulating the flight control panel and FMS (Flight Management System); attempting to help monitor airspeed/altitude/etc for [the Captain] (we had a jumpseater; who also helped with this); and trying to get our landing data/talk to Dispatch. Unfortunately; we also got ACARS NO COMM shortly after [coordinating] with ATC; so we weren't able to get landing data or talk to our Dispatcher. I used the speed cards for our landing numbers and increased VREF (Reference Landing Speed) (Flaps 45) by 10 KIAS (Knots Indicated Airspeed) as directed by the STALL FAIL QRH checklist. I used the landing distance data we had from ZZZ1 because we couldn't get new distances. Those were already conservative because ZZZ1 had runway condition codes of 3/3/3; and then I added 15% to our actual landing distance as directed by the STALL FAIL QRH. We still had enough runway to land in ZZZ2. While I was working on all of this; we got an additional EFIS COMP MON caution message; this time with the ROL flag. This one was intermittent; probably coming and going every few seconds for 15-30 seconds (which was quite distracting!). I never ran that checklist because by the time I was finished with the other QRH checklists; it had gone away completely.Shortly after this; Approach vectored us onto the ILS (Instrument Landing System) for runway XX. We broke out well above minimums and made a safe landing. The firetrucks were there to greet us next to the runway; but their lights were off until they started to follow us; so only a few passengers noticed them. We hadn't had time to make a PA during the emergency; but had previously warned the passengers about the possibility of a diversion due to weather. When we arrived at the gate; [the Captain] updated the passengers and apologized for not informing them earlier. None of them seemed upset by the situation.Needless to say; we were both shaken by what transpired while we were in the air. Both of us agreed that an engine failure would have been preferable to what we experienced. However; at least initially; the emergency did not seem to be taken seriously by anyone at the company. Maintenance told us that they would send contract maintenance out and then we could continue to ZZZ1. We told them that we were not interested in taking that airplane anywhere; under any circumstances. Then; we were told that a rescue flight was in the air and that we were going to fly our passengers to ZZZ1; and then continue on to operate our scheduled flight from ZZZ1 to ZZZ3. It surprised me that no one seemed to understand that we might need some time to decompress after the emergency. After talking to maintenance and scheduling; we talked to the Duty Pilot. He did ask if we were ok to continue flying. At that point; we had had time to sit down and talk together about what had happened and felt that we had decompressed enough to safely continue to ZZZ1. However adding another flight after that felt like too much. We told the Duty Pilot that we could take our passengers to ZZZ1; but that there was no way we were going to continue to ZZZ3 that night. Dealing with the emergency was exhausting; and even though we would have been within our duty time limits; and we had had some time to process the emergency; we were still in no shape to operate the flight to ZZZ3. Even after talking to the Duty Pilot; scheduling continued to insist that we would fly to ZZZ3 that night. In fact; they contacted me 14 times with schedule changes while we were in ZZZ2. Obviously; we could call in fatigued (and I would have done that); but I think that in this circumstance; it shouldn't come to that. Ultimately; we arrived in ZZZ1 so late that the ZZZ3 flight was removed from our schedule without input from us. In the future; I think that the effects on the crew of an inflight failure like the one that we experienced should be taken more seriously than they were in this circumstance.




Synopsis: CRJ-900 First Officer reported a diversion due to weather complicated by multiple system failures during the diversion.