The field chosen should be the longest available or, more specifically, the one with the longest into-wind run. To talk in terms of actual length may not be very meaningful; there are some parts of the country where 750 feet is regarded as long. However, the smaller the field, the less the margin for error, and you always want the largest margin possible. Normally you need minimum 750 feet but it depends on:
  • What you are flying
  • What the headwind component is
  • What the slope is

Landing corner to corner increases length.

BEWARE of wires

Assessing Field Size

Assessment of length by relating a field to the spacing of poles (240 feet) may be of value if time is available and the pilot is relaxed enough to do this. It is better, however, to know the areas where fields are small, and this you can find out by talking to experienced cross-country pilots. Instructors should know where not to send pilots on first or early cross-country flights.

Various features of the glider may also be significant in the selection of the field; if the approach angle is shallow – that is, the airbrakes are not very powerful – then even a tall hedge can effectively ‘cut off’ a hundred yards or so. If the glider has the wings set low on the fuselage, the ground-cushion effect is more significant than for a glider with a high wing (i.e. the glider will float a long way). This must be taken into account. Add poor speed control on the approach to these factors, then a field which might have been adequate may prove to be anything but!

On the benefit side is the fact that most modern gliders have very effective wheel brakes. If you have such a glider then it is worth bearing in mind the possibility of flying the glider on to the ground (as opposed to making a fully-held-off landing) and using the brake.

So, use relative sizes of surrounding houses, trees etc. as a guide. Beware of a small field surrounded by smaller ones. Check if the approach is obstructed, as obstacles on the approach decrease the usable field size by 8 times the height of the object.