Flight Crew Commercial
Other / Unknown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Weather / Turbulence
General Maintenance Action
Procedure
We took aircraft the aircraft round trip. We were in and out of IMC both there and back. Temperature was above freezing on first leg; but on return we momentarily picked up some trace ice. De-ice system was activated normally per the company SOP and aircraft POH. System was only used in the normal position for a few minutes. Later that afternoon while preparing to take the same aircraft for another flight; I was informed that glycol was added to the TKS fluid tank. Neither the captain nor myself had knowledge of this prior to departing and only became aware later that afternoon.
A C208 crew was informed after flight in icing conditions that the aircraft's TKS system was mistakenly serviced with glycol instead of the authorized fluid.