An all-metal flush riveted sailplane with fabric covered control surfaces, the Blanik is stressed for aerobatics and has held many two-seat records. It is equipped with DFS type airbrakes and Fowler-type flaps. The main wheel has an oleo strut shock absorber and is partially retractable.

A Blanik was involved in a fatal accident in Austria on 12 June 2010 when a wing spar failed at height, leading to separation of the wing and loss of control of the aircraft. The cause of the failure was attributed to fatigue. As a result, the manufacturer issued an emergency bulletin (AD) on 18 June 2010 mandating that each aircraft was to be grounded pending a full inspection of wing spars and compilation of usage patterns from logbook records.

Following inspection, the aircraft was permitted to fly on a non-aerobatic basis only. Following further discoveries from the accident investigation, this method of investigating for fatigue has not proved conclusive and so the type remains grounded by the EASA and the FAA.

According to Let company, the current situation may change in spring 2011 when new processes of control will be developed

Europe
Following the accident, EASA released a number of directives regarding all Blaník variants. Initially, the directives mandated the aircraft be grounded unless logbook records show that dual flying hours comprise less than 50% of the aircraft's total flying time. Further investigation into the original accident has shown that these limits and analysis of flight records (such data also not being guaranteed to exist) will not be sufficient to guarantee safe operation of the type.

United States
Emergency airworthiness directives were published by the FAA. A subsequent Airworthiness Directive (AD)disallowed use of inspection solely by 10X magnification because of the possibility of metal fatigue that might not be observed by this method. As a result, on August 30, 2010, so inspected L-13 Blaniks were again grounded pending further consideration. This AD covered all L-13s without regard to serial number or category.