Powered airplane competitions of the International Aerobatic Club have five categories, or levels of competition of increasing level of difficulty. The five categories are Primary, Sportsman, Intermediate, Advanced, and Unlimited.
The following paragraphs explain each category and show an Aresti diagram of the 2005 known compulsory aerobatic sequence for that category.
The Primary category is the most basic, entry level category of aerobatic competition. Pilots must demonstrate a spin, loop, roll, and competition turns.
The Sportsman category offers a greater challenge to the beginning competitor. It includes a greater number and variety of figures, including the hammerhead.
Sportsman competitors may design a “free” sequence. A free sequence is a sequence of the competitor’s design that satisfies constraints on the type of figures flown, the number of figures, and the total amount of difficulty of the sequence.
The Intermediate category adds the snap roll and some inverted figures. Intermediate competitors must provide a free program. If there is time at the contest they may also be required to fly an “unknown” compulsory sequence.
The Contest Director provides the unknown sequence to the competitors at least 18 hours before the competitors must fly it. Competitors may have practiced many of the figures in the unknown, but have no opportunity to practice the sequence before performing it for the judges at the contest.
You may see competitors doing a strange dance next to their airplanes as they rehearse the sequence on the ground before their flight.
The 2005 Intermediate Known included a snap roll on a forty-five degree down line, a roll integrated in a loop, an inverted exit and entry, and an inverted quarter-turn.
The Advanced category includes more challenging figures with multiple rolls and snaps on each figure and more inverted figures. The Advanced category adds the rolling turn.
Advanced pilots fly a known compulsory, free, and unknown compulsory sequence.
The 2005 Advanced Known included a snap on a vertical down line, a rolling three-quarter turn, and opposite point rolls.
The Unlimited category is the most difficult of all. Only the most capable pilots flying the most capable airplanes can manage the figures required in the Unlimited category.
Pilots flying Unlimited are flying at the level of air-show performers and world competitors.
The 2005 Unlimited Known included snap rolls on a vertical line up, combinations of snaps and rolls, and negative snap rolls. The sequence also included a tail slide.