Aerobatic aircraft are purpose-built or factory-certified for intentional flight outside normal attitudes — loops, rolls, spins, hammerheads, and the sustained inverted and negative-G maneuvers that utility-category or normal-category aircraft are not approved for. The key document is the aircraft's Type Certificate Data Sheet and data plate: a true aerobatic aircraft carries the "Aerobatic" category (or a combined "Normal/Utility/Aerobatic") and includes an approved G-load envelope, usually +6 G / −3 G or higher for competition types. Common types on the used market include the Pitts Special S-1S and S-2C (the benchmark of North American competition aerobatics), the Extra 300 and Extra 330 (the dominant German factory designs in IAC unlimited), the Christen Eagle (a homebuilt biplane), the American Champion Decathlon and Super Decathlon (the choice of many aerobatic instructors), the Citabria 7GCBC (a lighter, more accessible step-in), the Great Lakes 2T-1A (an open-cockpit biplane still popular on the air-show circuit), and high-end European imports like the Sukhoi Su-26 and Zivko Edge 540 that appear occasionally in the US market. Homebuilt aerobats (Steen Skybolt, Stolp Starduster) also trade regularly.
No separate FAA rating is required to fly aerobatics, but training matters enormously for safety. The International Aerobatic Club (IAC, an EAA chapter organization) offers a structured progression from primary through unlimited competition and sponsors aerobatic training at affiliated clubs across the US. FAR 91.303 prohibits aerobatics over populated areas, in controlled airspace, in Class B/C/D/E surface areas, within Federal airways, below 1,500 feet AGL, or when flight visibility is below three miles. FAR 91.307 requires a parachute for each occupant whenever intentional aerobatics are performed — this is the rule that makes aerobatic training in a two-seat aircraft straightforward (both seats carry chutes) but adds a recurring equipment cost. Upset Recovery Training (UPRT) programs, distinct from competition aerobatics, use aerobatic-capable aircraft to teach recovery from unusual attitudes and are increasingly required by airlines for commercial pilots.
Pre-purchase inspection on an aerobatic aircraft should go beyond the standard annual-equivalent check. The most important document is the airframe's G-load history, sometimes called a "G-log" — some owners and clubs maintain one voluntarily, though no FAR requires it. Ask the seller about the aircraft's competition and air-show history: hard negative-G maneuvers and sustained positive-G loads put stress on the engine mount, wing attach fittings, and control system hardware that routine cross-country flying does not. A pre-buy by an A&P experienced with the specific type (Pitts shops in particular are scattered but well-known in the aerobatic community) should include a careful control-cable and rigging inspection, a check of the inverted oil and fuel system if present, a spin-recovery check, and a close look at the engine mount and firewall. Aerobatic aircraft typically have lower airframe times than touring aircraft of the same age but can have high engine time from training use — verify time since major overhaul and the prop strike history independently.
