Introduction
On July 9, 2020, at 13:18 UTC, a PZL-Bielsko SZD-59 ACRO glider, registration OY-RUX, experienced a landing gear malfunction during approach to Vesthimmerland (EKVH) aerodrome in Denmark. The pilot executed a wheel-up landing on runway 29 asphalt, resulting in substantial damage to the aircraft. No injuries were reported.
History of Flight
The pilot performed a winch launch from runway 29 grass at 09:43 UTC, intending a cross-country soaring flight if conditions permitted. The launch was normal, but the pilot found it harder than usual to retract the landing wheel. After approximately 3 hours 20 minutes of flight, the glider returned to the EKVH area at 3,000 feet and began descending. During the descent, the pilot discovered the battery was depleted.
Entering the traffic circuit for grass runway 29, the pilot attempted to extend the landing wheel but could only move the handle about 25% of its full travel before it became stuck. The pilot transmitted a distress call: "4W can't take the wheel out – landing on runway 29 grass." After unsuccessful attempts to move the handle with both hands, and with other gliders occupying the grass runway, the pilot decided to land on the asphalt runway 29 and broadcast the change of plan. The glider touched down wheels-up on the asphalt.
Injuries to Persons
No injuries were sustained.
Damage to Aircraft
The wheel-up landing caused severe abrasive damage to the skin and frames of the lower fuselage forward of the wheel doors, as well as to both landing wheel doors. The wings and tail were undamaged. Paint and fiberglass from the glider left white scrape marks on the runway surface, but no damage to the asphalt occurred.
Personal Information
The pilot, a 23-year-old male, held a valid Sailplane Pilot License issued by the Romanian CAA on 24 April 2019 and a Class 2 medical certificate valid until 24 April 2024, with a limitation for defective distant vision. His total flying experience was 57 hours 40 minutes on all types, with 4 hours 40 minutes on type (SZD-59 ACRO), and 310 landings on type.
Aircraft Information
The glider was a PZL-Bielsko SZD-59 ACRO, serial number 590.A.06.007. Its Airworthiness Review Certificate was valid until 16 July 2021. Empty weight was 271 kg, maximum take-off mass 390 kg, and center of gravity range 145–275 mm. Total airframe hours were 586:20, with the latest maintenance on 7 May 2020. The actual take-off mass was 350 kg, and the calculated CG was 239.9 mm.
The landing wheel retraction and extension system comprised a cockpit handle connected to a tube, which linked via a rod end and nut to a lever arm on the landing wheel. The malfunction was attributed to this system.
The glider carried two batteries selectable by a cockpit switch; the switch label was missing.
Meteorological Information
At the time of the accident, conditions were Visual Meteorological Conditions (VMC) during daylight. A low-level forecast valid from 12:00 to 20:00 UTC indicated area 52d (including EKVH) was suitable for VFR flight.
Probable Cause
The Danish Accident Investigation Board concluded that the accident resulted from a technical malfunction of the landing wheel retraction and extension system, which forced the pilot to perform a wheel-up landing.