Casualties unknown

2017-07-29: SZD-59 Acro (SP-3765) — EPTO, PL

EPTO, PL

On July 29, 2017, a SZD-59 Acro (registration SP-3765) was involved in an aviation accident near EPTO, PL. Investigators recorded the probable cause as: The accident was caused by performing the fourth turn at too low an altitude in an area of rotors from the lee side of the forest, and loss of control by the pilot due to a sudden increase in vertical descent rate. This summary draws on records from the Polish State Commission on Aircraft Accidents Investigation (PKBWL).

Sourcesthe Polish State Commission on Aircraft Accidents Investigation (PKBWL)Primary reportUpdated 1785697035Data APIEditorial standards

On 29 July 2017, an SZD-59 Acro glider (SP-3765) crashed during landing at Toruń Airport after a competition flight. The pilot was uninjured. The investigation cited a low-altitude fourth turn in rotor turbulence and loss of control.

Introduction

On 29 July 2017, an SZD-59 Acro glider, registration SP-3765, operated by Aeroklub Częstochowski, was involved in an accident at Toruń Airport (EPTO). The pilot, who held a glider pilot license, was the sole occupant and was not injured.

History of the Flight

The glider was participating in the 8th FAI World Advanced Glider Championships and the 20th FAI World Glider Aerobatic Championships, held at Toruń from 27 July to 5 August 2017. After completing the known program competition, the pilot entered the airport traffic pattern with the intention of landing on runway 10. According to the pilot's statement, before the third turn he reduced speed from 170 km/h to approximately 140–150 km/h, maintaining that speed due to turbulence between the third and fourth turns. He extended the landing gear and began the third turn at about 200 m above ground. The fourth turn was initiated at 60 m altitude over the edge of a forest.

Accident Sequence

After exiting the turn and aligning with the runway, the glider entered an area of rotors downwind of the forest. The pilot lost control of the aircraft. The glider made a hard touchdown, likely on two points or tail-first, causing the rudder to separate from the vertical stabilizer. The main landing gear then collapsed, and the glider slid about 200 m further on its retracted gear before stopping. The pilot exited the cockpit unaided. Representatives of the State Commission on Aircraft Accident Investigation (PKBWL) arrived at the scene.

Findings

Post-accident examination revealed that the airbrakes were unlocked, and the landing gear lever was in the retracted (unlocked) position. An altitude measurement system (PHMD) recorded the flight parameters. The pilot was tested for alcohol (result 0.0 mg/l) and underwent X-ray examinations showing no injuries. The glider was assessed as repairable by the manufacturer.

Cause

The PKBWL determined the accident causes were:

  • Performing the fourth turn at too low an altitude in an area of rotors from the lee side of the forest.
  • Loss of control by the pilot due to a sudden increase in vertical descent rate.

A contributing circumstance was stress related to the competition flight. No safety recommendations were issued.

Probable cause

The accident was caused by performing the fourth turn at too low an altitude in an area of rotors from the lee side of the forest, and loss of control by the pilot due to a sudden increase in vertical descent rate.

Investigation report by the Polish State Commission on Aircraft Accidents Investigation (PKBWL). Original record: https://pkbwl.gov.pl/raporty/2017-1833/. This page is a structured re-presentation; facts and quotes are in the Panstwowa Komisja Badania Wypadkow Lotniczych (PKBWL), Poland.