Date: 201908
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Honda Jet
Operator: Fractional
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class B ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Window Ice/Rain System
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Time Pressure; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Diverted
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I and [copilot] were assigned a Part 135 flight to ZZZ with two passengers at standard weights; and less than 60lbs of cargo in the AFT cargo compartment; to depart at XA am local time; after our first flight with another passenger canceled. We had a bit over 2000 lbs/300 gallons of fuel onboard for the leg to ZZZ at FL390. The weather at ZZZ1 was clear and calm; the weather at ZZZ was clear and variable. As we reached our cruising altitude of FL390 we did our cruise checks; and all systems were normal. We then discussed how much time there was left for the arrival into ZZZ; approximately 29 minutes. As [copilot] grabbed her company iPad to start getting familiarized with the frequencies and runway; I also grabbed my company iPad to get the Vref landing numbers and put them in the box. At that moment [copilot] yelled SMOKE!! I turned to look at her and noticed white smoke coming from behind the right side of her seat; I then asked her if she had an iPad or phone charger connected to the A/C outlet that is in the same position as where the smoke was coming from; She said no!; and yelled let's descend now! I immediately performed our immediate emergency descent smoke and fire memory items; squawked 7700 and informed the Controller that we were [advising ATC]; and had to descend immediately with vectors to the nearest airport due to smoke in the cabin. The Controller replied ZZZ2 or ZZZ3 are the nearest. I requested vectors to ZZZ2 because of its long runways; professional fire department; and emergency equipment on the airport premises. The Controller cleared us to descend to FL240 and gave us a 330 heading. As we turned to ZZZ2 while rapidly descending with speed brakes deployed at 260-265 kts and a 5;000 [feet] a min rate of descent to FL240; flames broke out on the top right corner of the co-pilots windshield; I immediately asked [copilot] to grab the fire extinguisher that was behind my seat; and extinguish the flames with the halon bottle. I then informed the Controller that we had a spreading fire in our flight deck and required lower immediately; the Controller then gave us step down altitudes all the way to final approach. Please Note: We did not get any CASS messages for windshield overheat; but I still checked my QRH checklist; looking for window overheat; and electrical fire and smoke; nothing made sense. So after containing the fire; my focus was getting us on the ground ASAP; but was overwhelmed with communication confusion; because on many calls that we received; we could not properly hear the Controller over the speaker. I was going to go into my CDU and remove the window heat at high flight levels just to see if that would stop the burning; but I was told in ground class that the windows might shatter due to temperature inversions; so at that point I relied on the circuit breaker to do its job; if it was detecting a short. Knowing all this; I did not want to continue focusing my attention on this anymore; because my number one priority was to fly the plane; and not get distracted if we could contain the fire; just like we did. While descending and trying to keep the fire under control; [copilot] was trying to help me in every way she could; without getting burned from the burning plastic that was falling on her from up above the ceiling. One thing I do need to add is after speaking with the passengers; they said that very hot air was venting into the cabin; and that the floor and the side walls of the aircraft were real hot; this leads me into believing [we had] environmental air issues. I also recall [copilot] saying the vents are pushing hot air when we were about to land. I have to commend her for her extraordinary bravery; professionalism; and for performing her duties in the flight deck way above and beyond. Once [copilot] had everything under control; she checked in with our passengers to make sure they had their masks on; and were ok. Both passengers and [copilot] gave the thumbs up. While passing 15;000 feet I noticed the controls felt heavier and my trim had gone to full aft. I tried pushing the trim switch forward on my yoke; and the trim would not respond. I then tried manual mode and both switches; the trim forward and aft levers. I then pushed the normal mode trim push button and it would not turn amber. I asked [copilot] to help me push the yoke forward and she did; but once we went below 7;000 [feet]; the trims started working. I performed the descent and landing checklist while [copilot] was handling the radio communication; and trying to keep the fire under control with the halon fire extinguisher; we then briefed that after we land we would pull off the runway and evacuate. The Tower gave us wind direction and our runway choice; we requested Runway 1L which was direct with no further delays; the Tower brought it to our attention that the winds were not favoring that runway due to the 28kts and gusting winds. I told the Tower I needed no delays to Runway 1L. As I and [copilot] had already discussed the length of the runway and it was sufficient even with a tail wind; plus due to our smoke and fire emergency status; we both agreed that Runway 1L would be the right choice to get on the ground immediately. After we landed; the Tower asked us if we were going to evacuate on the runway; and we replied no we will turn into the intersection of S and F; the Tower thanked us. Then; we initiated our evacuation; [copilot] opened the boarding and deplaning main door; and evacuated the aircraft. [Copilot] directed the passengers to a safe area away from the aircraft. After everyone was out; and the aircraft was secure; I exit the aircraft and let the fire department go into the aircraft to check if the plane was still on fire; and it was. The fire department had to use their halon bottle to completely extinguish the fire. This is after the aircraft had already been shut down and secured. I advised the fire department that I would disconnect both batteries so that the aircraft would no longer have any sort of electrical current whatsoever..




Synopsis: An HA-420 HondaJet Captain reported smoke and flames in the cockpit; due to a window heat element malfunction; which necessitated an immediate diversion to the nearest suitable airport.