Caravan Undifferentiated
Flight Crew Commercial
Physiological - Other
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Aircraft Equipment Problem Dissipated; Flight Crew Took Evasive Action
Aircraft; Human Factors
During a routine flight with a flight time of approximately 50 minutes at an altitude of 4500 MSL; an OAT around +10C. TKS system on HIGH; inertial separator in bypass; heat on with the selector turned to the 9 o'clock position; the overhead vents opened; and side vents closed. I prepped aircraft for a normal winter's flight by doing a preflight test of the TKS system. All TKS panels were saturated with TKS fluid and all systems operated normally. After engine start and during taxi to the takeoff runway I turned the TKS system on high; and pulled the inertial separator to bypass. I maintained the system on high and inertial separator in bypass for entire flight. About 20 minutes into the flight I noticed a strange taste and a very faint odor of TKS fumes. About 5 minutes later I noticed the beginnings of a slight headache. I put my oxygen mask on for the remainder of the flight. After the flight I walked around got some fresh air and a drink of water and the headache was gone.On the return leg I turned the TKS on to the NORM selection for about the first 15 minutes of the flight then turned the system onto HIGH. Inertial separator in bypass; Heat on at 9 o-clock position and overhead vents open. On the return leg I did not notice any fumes or get a headache.The difference between the 2 legs was on the initial departure I started the system on HIGH on the ground during taxi; and on the second departure I started with NORM and ran on NORM for about 15 minutes. Another difference was the direction of flight. From initially I was flying into the sun and I'm sure the flight deck was much warmer.
After takeoff with the TKS system set to high; a C208 pilot detects fumes and develops a headache. Oxygen is used for the reminder of the 50 minute flight. On the return leg the TKS system is set to normal for the first 15 minutes then high and no odor is detected nor does a headache develop.