competition aerobatics

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 aviation authorities.
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 enforced.)

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.

Aresti symbol

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 bias.

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 Sportsman category.

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.

Aresti Catalogue

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.