A C208 pilot reported that following exposure to dusty conditions when the tks system was activated ...

Attributes
ACN	1175735
Time
Date	201405
Local Time Of Day	1201-1800
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Make Model Name	Caravan Undifferentiated
Operating Under FAR Part	Part 135
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Aerofoil Ice System
Person 1
Function	Captain Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Type 4000
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter Weather / Turbulence

Narrative:

C208 caravan tks equipped. While enroute IFR; encountered unforecast trace [of] ice. Tks switch was in high mode. Pilot observed tks fluid only flowing from the first two feet of wing and last two feet; no fluid flow on majority of both wings; aircraft had no ice protection with this tks system. Dusty air seems to clog the wings and render system not operational. Very dangerous; and unreliable. Tks system should be investigated.

Original NASA ASRS Text

Title: A C208 pilot reported that following exposure to dusty conditions when the TKS System was activated during icing conditions in flight the fluid flow on both wings was uneven or absent providing no protection.

Narrative: C208 Caravan TKS equipped. While enroute IFR; encountered unforecast trace [of] ice. TKS switch was in high mode. Pilot observed TKS fluid only flowing from the first two feet of wing and last two feet; no fluid flow on majority of both wings; aircraft had no ice protection with this TKS system. Dusty air seems to clog the wings and render system not operational. Very dangerous; and unreliable. TKS System should be investigated.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

A C208 pilot reported that following exposure to dusty conditions when the tks system was activated during icing conditions in flight the fluid flow on both wings was uneven or absent providing no protection.