A balloonist seeking a
country estate would write an advertisement in these terms: “Well-drained
field required, served by a well-paved access road. Must be in a
gentle valley, with high trees on the windward side, and situated far west
of restricted airspace”
In theory, a balloon can
be launched from anywhere; in practice there are topographical, climatic
and legalistic considerations that make some places much more promising
than others. Balloon crews find choice launch sites that fulfill
their requirements and persuade the landowners to give permissions for
regular flying. A phone call to the owner obtains the go-ahead for
a particular day. Crews can then use a familiar assembly point with
well-known characteristics.
As balloons fly with the
weather, and not through it, balloon pilots have considerations which do
not affect pilots of conventional aircraft. For instance, local ground
fog, 50-100 feet thick, would not bother the pilot of a light aircraft
intending to land some 200 miles away after a two-hour flight. But
it could be critical for a balloonist with a 15-mile flight plan.
Balloon pilots are greatly
affected by the speed and direction of the wind; the pilots of aircraft
only slightly. The aircraft pilot will make allowances for the wind
by calculating a course from A to B which takes account of the the amount
of drift at an angle to his track. At launch or landing he selects
a runway which allows him to face his aircraft into wind and gain lift.
The balloon pilot, however, cannot fly from A to B if the wind is flowing
in a different direction. He therefore derives his course from the
forecast wind direction, selects his approximate flight time and, if he
has a desired landing area B, plots a take-off site A. He then uses
wind direction changes with altitude to fly from A to B.
More commonly a balloon
pilot decides on an approximate flight duration - say 2 hours at 20 knots
- and selects his launch site accordingly. He can then give an approximation
of B from his knowledge of the prevailing conditions, but will not determine
his precise B until well into the flight. This is one of the essential
differences between balloon flying and most other forms of aviation.
Balloonists seldom have a destination in mind, but are more concerned with
enjoying themselves on a magical mystery flight.