Aviation Safety Letter 4/2004

2004-2005 Ground Icing Operations Update

In mid-July 2004, the Winter 2004-2005 Holdover Time (HOT) Guidelines were published by Transport Canada. Check out the following website for all the details: http://www.tc.gc.ca/eng/civilaviation/standards/commerce-holdovertime-menu-1877.htm.

A summary of this year's changes to the HOT Guidelines follows:

In the Type II and IV fluid tables, only a limited amount of data had ever been collected in temperatures below -14°C in snow conditions. During the winter of 2003-2004, testing was conducted with artificial snow makers at temperatures below -14°C using qualified Type II and Type IV fluids. This testing has led to a reduction in the -14°C to -25°C snow cells for the following fluids: SPCA Ecowing 26, Clariant Safewing IV 1957, Clariant Safewing IV 2001, Kilfrost ABC-s, Octagon Max-Flight and SPCA AD-480.

In addition, the fluid specific table for the Clariant Type IV Safewing Four fluid has been removed since the fluid is no longer commercialized.

Several years ago, a need was identified for a de/anti-icing fluid that had longer holdover times than a Type I fluid but a lower viscosity than a Type II or IV fluid, for use on aircraft with lower rotation speeds. Clariant produced the Safewing MP III 2031 ECO fluid, which met all the applicable requirements and is now qualified as a Type III fluid. Therefore a new Type III generic fluid table was produced this year based on the holdover times of this fluid.

There were no changes to the Type I fluid.

If you are interested in understanding or learning more about fluid testing and qualification refer to the following documents from the Society of Automotive Engineers (SAE): AMS 1424 and AMS 1428. These and other documents are available for purchase from the SAE at the following Web site: http://www.sae.org/.

There were no changes made to TP 14052, Ground Icing Operations Update; the reference document that should be used in conjunction with the HOT Guidelines.

If you have any questions or comments regarding the above, please contact Doug Ingold at INGOLDD@tc.gc.ca.

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