Date: 202009
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types
Detector: Automation Aircraft Other Automation
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Landed As Precaution
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During cruise flight and 10 minutes after coast out (80 NM East of ZZZZZ); DADC#1 failed resulting in a popped circuit breaker (DADC1) and noticeable fumes of burned electrical wire. After consulting with the Captain we decided to discontinue our oceanic crossing and divert to our departure airport ZZZ. Initially the Captain took control and we initiated a 45 degree right turn to leave our cleared course and initiate a descent to FL270 approximately 4-5 NM off course due to the smell of fumes. We ran the ERC items and maneuvered for a 25-30 NM parallel course Northwest to the coast out fix ZZZZZ and contacted ZZZ Radio for a clearance back to ZZZZ. Our clearance was to FL270 which we had reached by the time we received our clearance. Shortly after I received the controls back from the Captain and the rest of the flight remained uneventful. We elected not to declare an emergency because the fumes/odor subsided and we received direct ZZZZZ1 for the ZZZZZ1 1 arrival which was a straight course to the airfield and the traffic congestion was sparse; furthermore; ZZZ was the closest airfield and we didn't need emergency equipment standing by on arrival.


Second narrative: I was the Captain (PM) on Aircraft X flying from ZZZ-ZZZ1. During cruise flight at FL410 and 10 minutes past our coast out fix of ZZZZZ we experienced a DADC#1 failure. Soon after realizing which instruments had failed; the FO and I smelled an odor of electrical wire burning and noticed that the DADC1 circuit breaker was popped. I took control of the airplane and we both agreed that returning to ZZZ is the best choice considering our position; nature of the event; and the low IMC conditions at destination. I turned the aircraft on a 45 degree heading right of course to leave the airway and started my descent to FL270 at approximately 4-5 NM off course while in a turn to parallel the airway at 25-30 NM South and heading Westbound. Once we were established on our new turnback heading the odor subsided and we completed the QRH items and then contacted ZZZ Radio to let them know of the event and request a clearance back to our departure airport. At this point I gave back the controls to the First Officer and we decided not to declare an emergency because the odor/fumes cleared; we were on a course to the closest airport; and the traffic density was sparse. At coast in (abeam ZZZZZ) we contacted Center on VHF and were given direct ZZZZZ1 for the ZZZZZ1 1 arrival. The remaining flight and approach and landing was uneventful.


Synopsis: Flight crew reported that they diverted due to an electrical problem.