Date: 202108
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
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: PFD
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Workload; Human-Machine Interface; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Diverted; Flight Crew Landed As Precaution; Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I was acting as Pilot Monitoring on Aircraft X enroute from ZZZ to ZZZ1. We were climbing through FL270 just west of ZZZ2 when [the] Captain selected the cowl anti-ice switches to on position in response to a layer of clouds we were about to climb through. Within a few seconds of him selecting the cowl anti-ice; I noticed immediately that there was a loss of information on the Captain's side PFD (Primary Flight Display). The Captain had lost his white FMS course needle; a red RA flag appeared below the altitude tape; and on both PFD's; FMS1 in the FMA (which at the time was the active mode) had a red line through it. I called out this issue to the Captain; and he analyzed the situation to attempt to identify what information he had lost; which functionalities he still had; and which QRH checklist could be run to solve the issue. I do not recall what the active lateral mode in the FMA turned to after the Captain's side navigation information disappeared; but in troubleshooting; the Captain decided to transfer control of the aircraft over to me; as my navigation instruments were still working. We managed to arm and capture FMS2 on my side and continue flying the assigned route. We were still climbing in VS mode; now through FL280. I noticed that several functions of the FCP (Flight Control Panel) were now unavailable; including the SPD knob; and VS wheel; rendering it impossible to use any vertical mode of the autopilot. I informed the Captain that these issues may affect our ability to enter RVSM airspace; to which he agreed and informed ATC as such. ATC assigned us to descend now to maintain FL270. Unable to use any vertical modes of the autopilot; I had to disconnect the autopilot and hand fly down to FL270. I was still able to set an altitude in the altitude selector; so upon reaching FL270 I was able to reconnect the autopilot; which held altitude without issue.Meanwhile; the Captain continued to troubleshoot; looking through the QRH for what the issue might have been; and what checklist to run. He also notified the company of what components we had lost and called the flight attendants to tell them not to start any new service. At this point; ATC was aware of the situation; and an emergency had not been declared as; at the time; safe operation of the aircraft was not in question. As we were unable to identify what was causing the many failures; the Captain began suggesting a diversion to ZZZ2; which at this point we were only 25 miles east of. He began talking with ZZZ2 Maintenance and Dispatch over the radio to attempt to identify the problem and find the appropriate QRH checklist. After consulting Maintenance and Dispatch; together they were unable to identify the appropriate QRH checklist to run. The Captain and I discussed the possibility of a diversion. Given the descent and approach would need to be hand-flown on raw data (since the autopilot and flight director were rendered unusable beyond flying straight and level); all navigation information as well as RA on the Captain's side was unavailable; and there was inclement weather at ZZZ1 due to the approaching hurricane; we made the decision to divert to ZZZ2 (which at the time was VFR). Dispatch was made aware of the decision and notified ZZZ2 Ops; and told us they were prepared for our arrival into ZZZ2. We notified ATC of the decision to divert; and ATC began giving us radar vectors to ZZZ2. An emergency was still not declared as the Captain and I were still able to safely operate the aircraft in VMC and good weather conditions; and priority handling was not necessary; and ZZZ2 was not busy.Given that navigation information was only available on my side; I hand flew the rest of the flight while the captain made appropriate announcements; collected required information for landing; and set up the aircraft. We conducted a visual approach backed up by the ILS to Runway XXL at ZZZ2. The entire descent and landing was hand flown; as vertical modes were unavailable;including the ability to capture a glideslope. I was able to receive vertical and lateral information from the ILS; but the Captain's side was not; so he had to revert to cross-side information for the approach. His RA was also unavailable; so he had to make his call outs based on the information on my PFD. A normal; stable approach was conducted to a safe landing. We parked at Gate X. Maintenance came on board; and after a quick diagnostic; determined that the airplane would need to be hangared for further investigation. The passengers were deplaned and moved to a different aircraft. The cause of this event was maintenance-related. An unidentified failure occurred that resulted in a loss of multiple sources of navigation information and autopilot functions. Events like these can't always be prevented. I believe my training well prepared me for the outcomes of this event; and allowed me to return the aircraft to the ground safely.




Synopsis: CRJ-900 First Officer reported the Captain's PFD and other navigational equipment malfunctioned. The crew elected to divert and hand-fly the approach to landing.