Icing the Dash-8

According to the NTSB, more than 25 accidents occur annually due to inflight icing. Here is an account by a Dash-8 Captain with 5200 hours of logged time explaining icing experiences:

We started picking up Super Cooled Large Droplets or as I call it huge water drops which go beyond a foot after contact before they freeze on the windshield. If it goes farther, then it is getting behind our deicing equipment in my experience. Every time I have seen -8 degrees C and clear ice I had gotten an inch of ice within a minute and also every time requested lower right away.

The worst time was southeast of Aspen where it accumulated at more than 2 inches within the first minute. I lost my windshield completely, put the props to 1200 RPM and told my First Officer who was also a newer Captain flying right seat at the time we needed lower as soon as possible!

We were on vectors and within that first minute we had so much ice on us we had lost 15 KTS which is not normally something the Dash does at all in icing. I knew we could not climb out of it in time, so when ATC gave us lower I had the autopilot off and dove down at 3,000-4,000 FPM to 16,000 FT to get out of that temperature of -8 degrees C. At 16,000 FT we were still picking up light rime but it was +3 degrees C and not a concern anymore. However, that minute and a half or so at -8 degrees C and in Super Cooled Large Droplet conditions had dumped so much ice on the plane I could barely see out my left window at the boots and prop hub.

They were loaded with ice. I felt the plane was limping along. The plane was shaking violently with all the ice on the props. I had had the ice systems on maximum the entire flight. We finally broke out of IMC and [Center] wanted us to call the airport in sight, but I told them we needed to fly for a bit and get lower to melt all the ice as I couldn't see out my window to land. We got lower yet and by -2 to -1 degrees C the ice started breaking off and melting. We finally got cleared for the visual but by the time I started to configure for landing we had melted all the ice.

Excerpted from the Aviation Safety Reporting System (ACN 823412)