Ground de-icing, contaminated runways Flashcards
Holdover time is:
estimated time period that de-icing/anti-icing is effective in preventing ice accretion.
The most commonly used de-icing/anti-icing fluid -
Glycol
A runway is referred to as contaminated when more than __ % of the required runway surface is covered with the one of the following elements:
A runway is referred to as contaminated when more than 25 % of the required runway surface is covered with the one of the following elements:
(a) surface water more than three millimeters deep;
(B) slush or loose snow, equivalent to more than three millimeters of water;
(c) snow which has been compressed into a solid mass which resists further compression and will hold together or break into lumps if picked up; or
(d) ice, including wet ice
Definition of a damp runway:
means a runway of which the surface is not dry and on which the moisture does not give the runway a shiny appearance
dry runway definition:
means a dry runway which is neither wet nor contaminated, and includes those paved runways which have been specially prepared with grooves or porous pavement and maintained to retain effectively dry braking action even when moisture is present
Wet runway definition:
means a runway of which less than 25% of the surface is covered with water, slush or loose snow when there is sufficient moisture on the runway surface to cause it to appear reflective, but without significant areas of standing water
Braking coefficients:
Uncontaminated runway - normal dry surface:
Normal wet surface:
Icy surface:
- 3
- 15
- 05
Regarding icy surfaces, friction reduction is most pronounced at low or high speeds?
low speeds
The critical hydroplaning speed formula:
V = 9 x square root of P
V = hydroplaning GS P = tire pressure
bar to psi = bar x 14.5
Viscous hydroplaning:
Definition -
type of runway conditions -
The normal lubricating effect of water
All wet runways damp or heavy rain. Runways that lack microtexture
Dynamic hydroplaning:
definition -
Conditions -
when a tire is actually lifted of the runway and rides on a wedge of water
runways that lack macrotexture, standing water and high speeds
the most common type of hydroplaning?
Viscous hydroplaning
the most common type of hydroplaning?
Viscous hydroplaning
Reverted rubber hydroplaning:
Definition -
Conditions -
When heavy braking on a wet surface creates a steam barrier between the tyro and runway.
Heavy braking at low speeds
How to convert BAR to PSI:
bar x 14.5
