Date: 201812
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Challenger 350
Operator: Fractional
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Cruise
Aircraft component: Integrated Audio System
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight; Taxi
Result: Flight Crew Diverted; Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Human Factors

Narrative: We were assigned to a new aircraft that had just completed maintenance for an inoperative push to talk switch on the right side yoke. Prior to arriving at the airport we received a release from maintenance notification from the company. We immediately reviewed the maintenance electronic logbook to verify that it was indeed closed and that no other open write ups existed. Upon arrival at the aircraft we reviewed the paper logbook. The first page was the PTT (Push-to-Talk) write up that contained the proper corrective action and sign offs. I went to the left seat and did the preflight and flight planning while [my FO (First Officer)] cleaned and organized the cabin. All communications were done from the left during this period. When preparing to taxi; [my FO] tried 3 times to reach ground using the right PTT and could not reach them. We were behind several large buildings and hangers and just assumed it was blocking communications. I chose to do the comms from the left until take off. After takeoff we realized that the right PTT was still inoperative. When we reached cruise we located [the correct MEL] that would apply to the condition of the inoperative PTT switch and agreed to continue and write it up at the next stop. Soon after we received a message to divert without a reason. I executed the divert while [my FO] called the company for an explanation. We were told that we were flying an AOG aircraft. After landing we called the company again and were told that the technician that worked on the plane called the company after we took off and told them that he may have installed the PTT switch upside down. I went to the cockpit and tried the PTT in the opposite direction and it did transmit properly. We wrote up the plane again for the PTT switch being installed backwards.In the past we used the #2; or bottom radio for communications. Often in ZZZ we would have to switch to the #1; or top radio in order to establish communications in that area of the ramp. The action switched the comms from the right to the left radio. That past action affected my judgment when I chose to use the left PTT to communicate; thinking I was fixing the problem that I had dealt with before. There was no way for us to know what was going on behind the scenes as we prepared to take off. All the documents and notifications we received confirmed to us that the plane was airworthy.


Second narrative: [Report narrative contained no additional information.]


Synopsis: CL-350 flight crew reported a malfunctioning push to talk switch after maintenance had released it as repaired.