Date: 201912
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Light: Daylight
Aircraft: EMB-505 / Phenom 300
Operator: Fractional
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
ATC / advisory: Center ZZZ
Reporter organization: Fractional
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Physiological - Other
Second reporter function: First Officer; Pilot Flying
Anomaly: Deviation / Discrepancy - Procedural Weight And Balance; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Passenger
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: While climbing through FL250 both myself and my cockpit smelled a chemical odor that can be best described as a hot cigarette; like when it is first lit by a match. It soon got very noticeable/worse. We wondered if it was our passengers; so I turned to look. They were not smoking. I then asked if they smelled something; to which they emphatically said yes; with a bit of concern on their faces. With that knowledge that it was the whole aircraft involved; I decided to divert. There was no visible smoke detected. I contacted ATC and said we need to stop the climb. We then elected ZZZ as our divert field. We received vectors and a descent. At this point my copilot contacted Company and I took over as Pilot Flying. My First Officer went back to check on the passengers and the odor. He said they were fine and that the odor was definitely in the cabin as well. As I powered back for the descent; the odor dissipated fairly quickly. All of this was within 1 minute; from odor detection; verifying no smoke or smokers to dissipation of odor. I then decided to not advise ATC; but it seems ATC advise for us internally; as they asked a couple times for fuel and souls onboard. While approaching ZZZ; we switched back to my First Officer as Pilot Flying and me as Pilot Monitoring. While running the landing weight numbers for speeds; I noticed we were real close to max landing weight. The computer kept showing different weights at landing due to our vectors and power changes. As our passengers were slight in size and their bags weren't very heavy; I believed actual landing weight was lighter than what was showing. Approach and landing were normal. My First Officer accomplished a very soft landing. ARFF was rolled by Tower apparently and they followed us to the FBO ramp. After shutdown; I asked the passengers what they smelled and they said it smelled like hot cigarettes. A firefighter checked the plane with IR gear and found no hotspots. I asked him to check for any odor in the cabin. He said it smelled like a new car smell. While we cleaned the aircraft we could not detect any leftover odors.Because we allow smoking in our aircraft; we delayed donning our masks. As it was hard to determine what and where the odor was coming from. Our immediate thoughts was our passengers had lit up. But it didn't smell quite like cigarette smoke nor a burnt electrical circuit. After asking the passengers if smoking and receiving a no; we went into divert mode. We should have donned the masks. I'm not sure if we were getting used to the odor or just got busy. It wasn't getting worse like it first did and did subside soon after. Both of us did feel the odor in our throats and I felt it in my eyes. But not debilitating. Again the worst of it happened very quickly; while we were trying to figure out what was happening. I feel both me and my copilots experiences with smokers on aircraft in the past; delayed our donning of the masks.


Second narrative: Yesterday; we departed at approximately XA:30 local climbing out of the mid 20s; we experience fumes in the cockpit. Initially; we both believed that the passengers may have lit a cigarette. We both asked each other if we smelled a hot burning smell (similar to a cigarette being lit) and it seemed it was being distributed through the grasper vents. At that point; the PIC looked back and asked the passengers if they were smoking; they both said no. He asked if they could smell the odor; they said yes. At that point; we decided diversion would be the best action and we diverted into ZZZ. At that point I transferred the controls to the Captain and went back to brief the passenger that we would make a precautionary landing to investigate the fume smell. They seem OK and relived that we would be landing. While I was briefing them; I look and smelled for anything that might be an issue in the back. I could not identify anything for immediate concern in the cabin. When I went back to the cockpit; I contacted the Company to advise of the diversion. Once completed; the PIC transferred controls back to me and continued his Pilot Monitoring duties. He noted that according to the computer; that we would possibly be overweight for landing. I insured that the landing was smooth and we came to a stop gently knowing we were potentially overweight. Upon exiting the runway; we taxied to the FBO without further incident. While we did not officially call for an emergency; ATC had the ARFF in position and they followed us to the FBO.After having time to process the event; I realized the potential hazard of not having put on the mask; however; the odor that was present represented that of a cigarette being lit. Having been on several flight that we had smoking present; the smell made me not show immediate concern. After having looked back and found that smoking was not present our concern grew and we asked ATC for a level off and the power was pulled back along with the smell dissipating. By the time we landed; I could not smell the odor anymore.


Synopsis: EMB-505 flight crew reported a fumes event throughout the aircraft resulting in a diversion.