Date: 201711
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Light: Daylight
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
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 Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Fatigue; Physiological - Other
Anomaly: Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; General Physical Injury / Incapacitation
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: It was the final leg of the duty day and our flight had been delayed due to a late inbound aircraft. I felt slightly more fatigued than normal prior to the start of the flight. Before the inbound aircraft had arrived at the gate I had complained to the crew of some minor cold symptoms; but I thought I was still fit to fly. We decided to proceed with the flight as normal and we accepted the flight release. After push back there was a lengthy delay in taxi time and it took a great deal of time to reach the runway departure point. Upon reaching the departure point I resolved that I was still feeling good and we proceeded to depart. Everything was normal up until about an hour or so into the flight at cruising altitude. We were cruising at 38;000 feet and getting close to about an hour and 20 minutes left on the flight time. I began to feel cold and grabbed my jacket to cover up and keep warm. As time progressed into the flight I started to break out into a cold sweat along with a warm body temperature. It was at this time I feared that my cold symptoms were worsening and my body temperature was beginning to elevate. To make matters worse I started to feel an elevated heart rate and shallow breathing. At this point I decided to inform the captain that I might be feeling symptoms of hypoxia. The captain immediately checked pressurization of the aircraft and we both crosschecked that the pressurization was normal in the cabin and there was no need to don the oxygen mask. However; as a precautionary measure we decided that I should wear the O2 mask and try breathing normally to see if the symptoms would improve. I tried to take normal breaths from the O2 mask; but my symptoms only worsened gradually. We also asked for a descent to a lower altitude to get to a lower cabin pressure to see if my breathing would improve. This also did not help me. The captain inquired at this point that I might be getting sick. I agreed with the captain and said to him that if the symptoms worsened I might like to deviate from the planned course for a landing at the nearest airport. We decided to continue on course for what seemed like another 20 minutes until I decided that my symptoms were not getting any better and I was becoming increasingly ill. At this point I became concerned about my ability to safely perform my duties as pilot monitoring and as a side of caution for my fellow crew and passengers I asked that the captain would [advise ATC] and divert to the nearest suitable airport. We utilized CRM and the captain made a precautionary declaration to ATC that we needed to divert. We were cleared and began our course change. The captain contacted the company via ACARs and informed them of my condition. He also got in touch with STAT MD for the required medical information on my physical state and other information. I did my best to perform my job functions and provide the captain with the landing weather ATIS and runway numbers; but my symptoms were getting bad with what seemed like an increasing body temperature and possible fever. I informed the captain of my state of being and from there we requested emergency medical equipment on the ground. There was light snow in ZZZ but the weather conditions were good for a normal CAT I ILS and we were able to get down quickly. We arrived at the planned gate with the emergency equipment standing by. The captain opened his cockpit window and we were greeted by medical staff. They inquired my condition and concluded that I might be dehydrated and that they would perform further tests to see about my condition. At this point the flight was safely terminated and I was escorted into the terminal for a blood and temperature check. It was concluded by medical staff that I was running a high fever of 103 degrees with some dehydration along with it. After further medical care it was determined that I had a cold virus that caused me to have the fever. The fever is what gave me the symptoms of shallow breathing and rapid heart rate. In the interest of safety we did not take these symptoms lightly; and I believe we made the best decision to terminate the flight early. Cold and fatigue symptoms should not be taken lightly. If these symptoms occur in the future I will call off the trip or ask for a fatigue call. Better communication with the crew and company on my condition prior to departure is also important.




Synopsis: A regional jet pilot reported experiencing multiple physical symptoms resulting in an inability to continue the flight. A diversion to a suitable airport to seek medical help was accomplished.