Winter Thoughts

You just shot the best ILS you have made in two years after flying through a fast moving winter storm and you are patting yourself on the back. The landing runway has a Northeast heading, but the front has come through, the temperature has dropped and the wind is now blustery and shifting rapidly to the Northwest. You arrest the descent and begin the flare. You touch down and suddenly you say to yourself, “What the heck is going on?” The aircraft weather vanes and begins to head off the runway! Before you know it you have crashed through a snow bank and come to a stop in the snow covered safety area. You ask yourself what went wrong? The winter weather transition has begun and with this you need to think about flight in icing conditions, but don’t forget to think about airport field conditions. Each year accidents and incidents occur around the country on airport surfaces because pilots fail to check and anticipate weather related surface conditions at their destination airport or the pilot lacks the experience to deal with the conditions they encounter. By carefully reviewing weather reports and forecasts, along with the NOTAM D, NOTAM L and even calling the destination airport manager for an update you can fly more safely. The Notice to Airmen D or Distant NOTAM will provide you with the latest reported runway surface conditions or closures for the airport. You can obtain this information by calling a Flight Service Station (FSS) or access DUAT, Meteorlogix, WSI or similar weather computer provider. The NOTAM L or Local information NOTAM provides surface conditions and closures for taxiways and ramps, however the NOTAM L is not available on computer weather systems and must be obtained by calling Flight Service or by calling the destination airport directly. A NOTAM reporting weather related runway, taxiway or ramp conditions will be time sensitive. To illustrate what I mean consider this. You call Flight Service at 1900L and find out Westerly Airport’s last condition report at 1730 Local time was RWY 7/25 THN WSR (Runway 7/25 Thin Wet Snow on Runway). You know it has been snowing continuously at a rate of an inch and hour. With this information you can see that the NOTAM, which is now an hour and a half old is no longer valid. There will be upwards of an inch of snow or more on the ground. Anticipating trends will prepare you.

In the opening scenario, conditions changed rapidly. What might have been reported earlier as PTCHY THN WSR, (Patchy Thin Wet Snow) and PTCHY THN WATER, (Patchy Thin Water) has now frozen and glazed most of the runway pavement with thin ice after the frontal passage and rapid temperature drop. Anticipating wind changes and temperature drops to freezing or near freezing conditions will reduce landing surprises. Remember, it does not have to be IFR to encounter winter conditions. Many folks will get out and fly right after a storm in VFR conditions and fail to check on field conditions and arrive surprised. They discover the field is closed. The airport hasn’t been plowed or conditions are worse than reported, so don’t take-off without checking the NOTAM’s. If the NOTAM for field conditions is not up to date and you can’t reach the airfield by phone, you must consider what you will find upon arrival. Weather reports and forecasts along with the timeliest NOTAM will help you make a decision. An alternate airport may be the best choice. Many factors control airport snow removal operations, staff size, available equipment, equipment breakage and storm intensity. Most airports make every effort to remain open during a storm, but might be impeded by the examples given. Don’t be afraid to call the airport you are planning to fly into and ask when the airport is expected to open. A call will save time, money and embarrassment. Patience will be your ally in winter flying! Remember winter weather changes what we often take for granted. Runways may be open, but some taxiways and ramps may be closed, because of the storm. The NOTAM L will inform you of those ramp and taxiway closures. It is not unusual to find snow piles and snow islands at some airports. Caution should be exercised when taxiing to and from ramps for wing tip clearance, especially at night. Guidance signs may be obscured too by drifting or piled snow. Airport diagrams can be handy when this happens.

When the storm is over snow crews at smaller airports go home at night. The Airport Facility Directory will state in the remarks, “ field conditions unmonitored when the airport is unattended.” This note warns you to expect the unexpected, because no one is watching the field overnight! The airport will not update the NOTAM or correct conditional changes until morning. Strong winds will often create finger drifts that can cross a runway and can envelope an entire taxiway section in an overnight. Melting snow will wet surfaces during the day, which freeze after sunset creating a landing and taxiing hazard, so care should be taken when flying in and out of unattended airports at night. Airports often remove tie-down lines during the winter for snow removal. Bringing your own is recommended. Keeping a hammer and screwdriver handy for chipping out the ice in tie-down rings can be beneficial. Winter really provides some of the best VFR flying of the year, clear skies, visibility and great engine performance. You just need to include Field Condition Reports in your pre-flight planning. Don’t get mouse trapped by failing to check it out before you depart. Instructors should make sure their students are prepared, too. When you plan the next breakfast flight or needed cross country, put a little extra time into reviewing the NOTAM D and NOTAM L’s when you pre-flight the trip. By doing so, you will know what to expect, be able to plan for the condition and have a safer flight.
                                                                                   

By James Cowley