AC 150/5200-30C Airport Winter Safety and Operations

Issued 12/09/2008, this advisory circular (AC) provides guidance to assist airport operators in developing a snow and ice control plan, conducting and reporting runway friction surveys, and establishing snow removal and control procedures.

Click to download ADVISORY CIRCULAR AC150/5200-30C

Subjects included in this Advisory Circular:

• Snow and Ice Control Plans

• Snow Clearing Operations and Preventive Measures

• Runway Surface Assessment and Reporting

• Runway Condition Reporting

• Runway Friction Surveys

• FAA-Approved Runway Friction Measuring Equipment.

• Friction Assessment Reporting

• Requirements For Runway Closures

• Continuous Monitoring

• Development of Recommended Snow Bank Height Profiles

• FAA-Approved Decelerometers

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Definitions contained in Advisory  Circular AC 150/5200-30C:

a. Contaminant. Any substance on a runway. For the purposes of this AC, references to contaminants mean winter contaminants such as snow, slush, ice or standing water.

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b. Eutectic Temperature/Composition. A deicing chemical melts ice by lowering the freezing point. The extent of this freezing point depression depends on the chemical and water in the system. The limit of freezing point depression, equivalent to the lowest temperature that the chemical will melt ice, occurs with a specific amount of chemical. This temperature is called the eutectic temperature, and the amount of chemical is the eutectic composition. Collectively, they are referred to as the eutectic point.

c. Ice. The solid form of water consisting of a characteristic hexagonal symmetry of water molecules. The density of pure ice is 57 lb/ft3 (913 kg/m3), which is 9 percent less dense than water. Compacted snow becomes ice when the air passages become discontinuous at a density of about 50 lb/ft3 (800 kg/m3).
d. Snow (on the ground). A porous, permeable aggregate of ice grains, which can be predominately single crystals or close groupings of several crystals.

(1) Dry Snow. Snow that has insufficient free water to cause cohesion between individual particles. This generally occurs at temperatures well below 32° F (0° C). If when making a snowball, it falls apart, the snow is considered dry.

(2) Wet Snow. Snow that has grains coated with liquid water, which bonds the mass together, but that has no excess water in the pore spaces. A well-compacted, solid snowball can be made, but water will not squeeze out.

(3) Compacted Snow. Snow that has been compressed into a solid mass that resists further compression and will hold together or break up into lumps if picked up.

e. Slush. Snow that has water content exceeding its freely drained condition such that it takes on fluid properties (e.g., flowing and splashing). Water will drain from slush when a handful is picked up. This type of water-saturated snow will be displaced with a splatter by a heel and toe slap-down motion against the ground.
f. Patchy Conditions. Areas of bare pavement showing through snow and/or ice covered pavements. Patches normally show up first along the centerline in the central portion of the runway in the touchdown areas.
g. Primary Runway. A runway expected to be used under the existing atmospheric and storm event conditions where most of the takeoff and landing operations will take place.

h. Secondary Runway. A runway that supports a primary runway. Takeoff and landing operations on such a runway are generally less frequent than on a primary runway.