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Old 4th Jan 2011, 18:44
  #33 (permalink)  
FEHERTO
 
Join Date: Dec 2007
Location: VIENNA
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The reason, why a lot of airlines, taking the subject very serious, do not use brand name tables are various:
1. Very often, onyl a few data points are used to create the tables (normally done by APS Aviatin for TCA and FAA), being not really fully representative.
2. Too often the fluid has lost a lot of viscosity, and especially the UK are a place, where you find a lot of degraded fluid. Caused by the heating of the excessive heating of 75:25 mix often used (mainly as one-step).
3. The hold-over-time tests are done by pooring fluid on a tets plate and counting the fluid failure during differnet conditions related to temperature and active precipitation. The fluid placed on the plates is normally between 3 to 4 mm, getting thiner with time. If you spray too less fluid (film thickness less than 1 mm), you simply cannot get the hold-over-time as published in tables.

Using the brand name tables require that you really know the fluid conditon as well as taht enough fluid is used for anti-icing.
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