Date: 201911
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: EMB-505 / Phenom 300
Operator: Fractional
Operating under: Part 91
Mission: Passenger
Flight phase: Cruise
ATC / advisory: Center ZZZ
Aircraft component: Pressurization System
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; Flight Crew Diverted
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: While in cruise; enroute from ZZZ1 to ZZZ2; at 41;000 ft. the DUCT 1 OVERTEMP CAS (Crew Alerting System) illuminated. I elected to continue to fly the plane as PF/PIC (Pilot Flying/Pilot In Command) and asked the PM/SIOE to run the QRH (Quick Reference Handbook) procedure. We initiated a descent to 36;000 ft. as per the QRH. The single passenger we had on board came up and was unhappy with his temp control. I explained the situation to him. That it was being caused by the Duct Overtemp and at this time we would be continuing to ZZZ2 but there was a chance if the duct did not cool we would have to divert. I assured him everything was safe at this time and I would let him know what we ended up with. No sooner had the passenger returned to his seat that the DUCT 2 OVERTEMP CAS illuminated. At that time we switched gears from the single duct OVERTEMP QRH to the DUAL DUCT OVERTEMP QRH procedure. We immediately requested 10;000 ft. from ATC (Air Traffic Control) and mentioned we were having pressurization issues. They began giving us incremental descent instructions. At that point we [requested priority handling] to expedite the descent. We were then given a heading and approval to descend to 10;000 ft. Looking at the flight map I saw ZZZ was 70 miles in front of us. Knowing we had to complete the QRH procedure and take care of the briefings for a diversionary airport we elected to divert there as the timing would work great. We told ATC and they gave us direct ZZZ. We reached 10;000 ft. and asked for lower and were given 6;000 ft. At 6;000 ft. we removed our oxygen masks. I looked back to check on the passenger and he came up to me (seatbelt sign was on). I gave him a test briefing and he was upset about the diversion. At 6;000 ft. I checked the ECS (Environmental Control System) page and noted both ducts were now cooled and other than being depressurized we had no other issues. We elected to cancel our emergency status with ATC. We continued to ZZZ; landed and taxied in.


Second narrative: We were in cruise at 41;000 ft. when we received a DUCT1 OVERTEMP CAS (Crew Alerting System) message. We began addressing the CAS with the associated QRH (Quick Reference Handbook) checklist. While waiting for the 1 minute required we reviewed our next options and decided to descend to 36;000 ft. should we need to address the next items on the QRH. Once level at 36;000 ft. we continued with the QRH. The QRH required the environmental controls off. Shortly afterward the passenger came forward and inquired as to why he could not control the temperature and we explained that we were experiencing an issue and were assessing the situation with the checklist and to expect the temperature to get a little colder until we could remedy the situation and we apologized for any discomfort. We then received a DUCT2 OVERTEMP in addition to ZZZZZ and decided to descend and switched to the DUALDUCT OVERTEMP QRH item and requested 10;000 ft. to deal with any possible resulting pressurization issues; and we donned our oxygen masks per the QRH. We began the descent and Approach began trying to step us down in altitude so we [requested priority handling] and immediately initiated a descent to 10;000 ft. and looked for options to land as soon as practical. We decided to divert to ZZZ as the most practical solution and began working that direction. Once we were in a safe non-critical moment we advised our passenger of the diversion and the emergency status and we prepared for a visual approach into ZZZ. We had a successful landing without further incident.


Synopsis: Flight Crew flying EMB-505 aircraft encountered pressurization problems in cruise.