Driving to the airport was not going to be fun.
I would much rather be in bed, especially since it was 5:30 in the morning. Luckily, I get paid to do what I love, fly.
Aside from looking at the weather channel the night before, the falling snow and slick roads made it obvious that today’s flight would prove to be a little bit more work than normal.
Once I got to the airport, I checked the weather and saw there would be light snow that would intensify later in the day to moderate snow.
There was no way we could get to the runway after startup without having a contaminated airplane, meaning snow on the wing.
The latest PIREPS and AIRMETS showed light to moderate in-flight icing at the worst and no SLD threats.
It looked like we are going to go flying… After we get de-iced!
There are two parts of the deicing fluid process although part two isn’t always necessary …
1. De-Ice with Type I fluid
- Heated Fluid
- Orange in Color
- Made to remove contamination from the airplane
- Sometimes all you need is Type 1 if there is no falling precipitation
2. Apply Anti-Ice if needed with Type IV
- If using Type IV you must first De Ice with Type I
- Not heated
- Green in Color
- Will run off the plane during takeoff
- You will have a better hold over time then if you only applied Type I fluid
- Apply Type IV if there will be a taxi delay or when conditions require
The passengers had just arrived and we started up and began to taxi over to the deice pad in our King Air 350. In order to de-ice in the turboprop, we need to shut down, as the blades could cause a hazard to the de-ice crew.
Now that we are shut down we need some important information.
- Our Temperature is -5c/23f
- We have Light Snow falling.
- Our King Air has an Aluminum wing
Find where the Outside Air Temperature of -3/-6 row meets the Yellow Light snow column. You should get a time of 0:08-0:14.
We have between 8 & 14 Minutes (Let’s just say 8 to be safe) to finish the de-icing, startup, and taxi to the runway. At smaller airports with no delays, this may be possible, but 8 minutes is pushing it.
If 8 minutes pass and we aren’t airborne our holdover time will expire. For Part 91 planes, like us, we can still go if we go and feel the wing for contamination or visually check it from the inside (I always physically feel the wing)
If we were at an airline and our time expired we would have to go get deiced again!
Whenever I am in doubt I physically check the wing. (If you ever are in doubt, physically feel the wing)
With a possible departure delay, plus having a long way to taxi to the runway, I need a better holdover time and elected to have the Type IV fluid applied.
Left to Right ~ Using the conditions of Light Snow at -5C and with a 100/0 Concentration how much time will we have a minimum?
A. 8 Minutes
B. 40 Minutes
C. 20 Minutes
< Scroll Down For Answer >
C. 20 Minutes ~ Much Better!
* Your holdover time begins when the crew first applies the Type I de-ice fluid*
After communicating with the crew about fluid types, concentrations and temperature they begin a counter-clockwise sweep de-icing the plane with Type I fluid.
Before beginning the Type IV they will check with us to make sure we are happy with the de-ice.
When the crew finishes the Type IV fluid application we start up and begin our taxi for departure. After checking the wing one last time we depart!