For operations at nonaircraft fields, special considerations  must be evaluated. Permission is necessary to use private  property as an airstrip. Locate the area on an aeronautical  sectional chart to check for possible airspace violations or  unusual hazards that could arise by not knowing the terrain  or location. Avoid loitering around residential structures and  animal enclosures because of the slow fl ight characteristics  of WSC aircraft and distinct engine noise. While selecting a takeoff position, make certain the approach  and takeoff paths are clear of other aircraft. Fences, power  lines, trees, buildings, and other obstacles should not be in the  immediate flightpath unless the pilot is certain he or she is able  to safely clear them during takeoff and landing operations. Walk the entire length of the intended takeoff and landing area  prior to departure.  [Figure 5-3]  Look for holes, muddy spots,  rocks, dips in the terrain, high grass, and other objects that can  cause problems during takeoff and landing. Physically mark  areas of concern with paint, flags, or cones. Uneven ground,  mud, potholes, or items in fields such as rocks might not be  visible from the air. Plowed rows and vegetation are larger  than they appear from the air. Unfamiliar fields can make  suitable landing areas for emergencies, but should not be used  as intended landing areas. Extreme caution must be exercised  when operating from a new field or area for the fi rst time.  A pilot must become familiar with all available information  concerning the flight, including runway lengths at airport of  intended use, takeoff and landing distance accounting for  airport elevation and runway slope, aircraft gross weight,  wind, and temperature. For a cross-country flight not in the  vicinity of the takeoff/departure airport, information must  include weather reports and forecasts, fuel requirements,  and alternatives available if the planned flight cannot be  completed. There are many sources for obtaining a weather briefi ng,  such as www.aviationweather.gov, www.nws.noaa.gov, 1- 800-WX-BRIEF, and a variety of internet sites that specialize  in local and regional weather.  Understanding the overall weather in the region being  fl own provides an overview of conditions and how they can  change during flight. Fronts, pressure systems, isobars, and  the jet stream determine the weather. There are a number of  information resources from which to find the regional view  of weather systems, observed and predicted. Surface analysis  charts show these regional systems, which are common on  weather internet sites and TV broadcasts.  [Figure 5-4]  Review  the Pilot’s Handbook of Aeronautical Knowledge for a  comprehensive understanding of weather theory, reports,  forecasts, and charts for weather concepts covered throughout  this weather section.  Weather is a determining factor for all fl ight operations.  Before any flight is considered, pilots should obtain regional  and local information to first determine if the predicted  weather for the planned flight is safe.   Weather  Regional Weather  Prefl ight Actions Figure 5-3. Fields that look like good landing areas from the air  may actually be hazardous. Figure 5-4. Standard surface analysis showing fronts, pressure  systems, and isobars (top) and composite surface analysis which  adds radar and infrared satellite to show cloud cover (bottom). 5-3