The competition and
air-show sequences, as the flights are called, must be flown with
split-second timing, precise speed and altitude control, constant
calculation for such variables as wind and temperature, and very precise
planning on the pilot's part. Any wrong turn, misplaced pullout, and roll
in the wrong direction can put the pilot out of the running because of a
zero score by the judge.
The competition sequences
are flown in an aerobatic zone over the airport commonly called the BOX.
The BOX is an area 3300 feet square with the top at 3500 feet. The bottom
depends of the level of competency of the individual pilot. Beginners have
to fly higher whilst the unlimited pilot is trained to get to the bottom
of the BOX. In competition the lower limit is 330 feet or 100 meters. At
air shows the display pilot has his own limits which are approved by the
There are 5 acknowledged (FAI/CIVA) levels in aerobatics
Each competition may have
between five and nine judges. They are positioned between 150 and 250
meters back from the edge of the box, facing the A-Axis. They declare an
official wind parallel to the A-Axis which either blows from their left or
right (depending, obviously, on weather conditions.)
Corner judges monitor a pilot’s excursion from the box and assign
penalties. Penalties are also incurred by flying below the floor (which
could lead to disqualification) and above the ceiling (generally not
Every judge has
his assistant who is writing down the scores. The judges grade each
individual figure as well as how well the sequence is positioned within
the BOX. The figures are graded on factors like precision of the lines and
angles, symmetry of figures and other factors spelled out in the catalogue
used by all pilots. Each judge has a copy of the figures the pilot will
fly. On these sheets the figures are graphically represented by symbols.
The system of graphically depicting the figures was devised by Jose L. Aresti of Spain for the use in World Aerobatic Championships (WAC). It has
been successfully used for many years.
In addition to the
graphical symbol, each figure is assigned a difficulty coefficient or
"K-factor" based on the difficulty involved in performing the figure. The
K-factor and the grades given by the judges are multiplied to derive the
points for that figure. A computer then adjusts the totals to account for
Some performers sky dance.
That is, they perform an aerobatic sequence to music that is heard by both
the spectators and the pilot.
There may also be a Classic class for airplanes without inverted fuel and
oil systems. The sequences flown are very similar to those flown in the
Within each class, each pilot flies several programmes. They are:
Known: Determined each year by the FAI, which is flown by all
contestants at all contests all year long.
Free: In this program, each pilot is given the opportunity to
demonstrate his personal flying skills, creative talent and his aircraft
performance by designing his own sequence.
Unknown: This program is made known to the contestants only 24
hours before the competition and the figures are chosen by the contest
chief judge. The pilots must fly it without prior practice. (For classes
Intermediate and above.)
4-minute Free: Only the top unlimited pilots might be invited to
fly this final program. It is for this program that new figures are
sometimes flown as pilots strive to display their creativity and superior
skills as performers.
The Aresti Catalogue is
the Fédération Aéronautique Internationale standards document outlining
the aerobatic manoeuvres permitted in aerobatic competition. Designed by
Spanish aviator Jose Louis de Aresti Aguirre, each figure in the catalogue
is represented by lines, arrows, shapes and numbers representing the ideal
form of the manoeuvre.
Solid lines represent "upright" or "positive-g" manoeuvres. Dashed lines
represent "inverted" or "negative-g" manoeuvres and are usually coloured
red. Stalled wing manoeuvres such as spins and snap (flick) rolls are
represented by triangles. Arrows represent "rolling" manoeuvres (with
numbers representing the extent/segments of the roll).
Each manoeuvre is also assigned a "K" or difficulty factor. During
aerobatics competition, the judges mark the execution of each manoeuvre
out of a possible score of 10. These marks are then multiplied by the "K"
factor of each figure to give a total score for the flight.
The Aresti catalogue has been in official use since 1964.