Useful Practices - Snow and Ice Control
Submitted by Jim Moriarty, Fleet Manager, Metropolitan Airports Commission
Airport snow and ice control is extremely important, regardless of the size of an airport or the aircraft using it. Snow and ice control on the last third of a runway is especially critical, as this area must offer a clear pavement if a pilot decides to abort a takeoff.
Snow plans and other techniques
Every airport should have a current "snow plan" that describes in detail snow and ice control and removal operations. A snow plan must be current, short, factual, and practical, and should be reviewed by the airport owner's legal staff before it is submitted to the FAA Regional Office for approval. FAA Advisory Circular 150/5200 outlines the requirements for a snow plan.
The snow removal plan at Minneapolis/St. Paul International Airport requires runways to be cleared within thirty minutes of closing. The Metropolitan Airports Commission (MAC) owns a Saab sedan that is used to test friction and provide an objective number indicating friction conditions. After each storm, airport users and MAC personnel hold a snow removal critique meeting during which the snow event and removal are discussed, along with ideas for aiding the next snow event.
One method for controlling drifting snow is a Canadian snow fence. This is created by using a snow blower to blow a trench parallel to the airport pavement once the ground is frozen. Because this trench is an area of low pressure, it attracts blowing snow and prevents it from blowing onto the pavement. This trench creates an area of lower pressure, and blowing snow is attracted to the low spot. This prevents the snow from blowing onto the pavement. The width of the trench is generally determined by the width of the blower, with ten feet being typical.
NOTAMS and Airfield Condition Reports
A Notice to Airmen (NOTAM) must be issued to alert pilots of plowing, closed pavement surfaces, lighting, and navigational aid (NAVAID) conditions. NOTAMS should also warn pilots of any hazards. For example, obstructions such as snow piles must be listed on a NOTAM. Pin or pillow drifts are considered obstructions as well, as they can ruin an aircraft's landing gear. Pavement inspections must be repeated periodically in order to generate continuous updates on the airfield condition and to determine when and if re-plowing is needed.
At MSP, a NOTAM is issued any time a runway is closed, regardless of the duration. Yellow lighted Xs are placed on runway ends to further alert pilots. MAC maintenance staff tries to give pilots at least one-hour notice of pavement closings, but may only provide thirty minutes if conditions warrant.
Airfield Condition Reports, issued by airports to give pilots information on pavement conditions, must be specific, accurate, timely, and use approved FAA phraseology.
Lighting, markings, signage and NAVAIDS
Keeping signs, markings and lighting clear is extremely important for safe operations at an airport. NAVAIDs and light couplings are to be checked after plowing to insure that they were not damaged and are operating correctly.
The windsock is an important element for pilots, and so should be checked frequently by airport owners or maintenance staff. Local police can also be charged with checking that the windsock is lighted during their periodic airport inspections. The airport owner must take responsibility for the windsock condition and ensure that it is always lighted.
According to FAR Part 139, an airport with three burned out runway or taxiway lights in a row must close. For unlighted pavements, three non-functioning pavement delineators in a row require that the airport close.