The ASK 21 is the most produced and most successful training glider in the world, manufactured by the company Alexander Schleicher. Worldwide, it is one of the most favoured training aircraft in the gliding sector, also due to its broad range of uses including stunt, training, overland and competition flying. Thanks to its low all-round weight, a higher towing level is reached when winch launching, compared to similar double-seaters, which allows for improved thermals. Serviceability, good flight characteristics and a solid build typify the 280 kilometre/hour fast ASK 21. Glass fibre synthetics are used in the centre deck section and T-tail, offering enormous bearing strength. The ASK 21 is capable of sustaining extreme loads of 4 to 6.5 Gs as a result. These values allow for a wealth of stunts to be performed, even including loopings.