Covering form of preliminary or final report
| Date of event : | 2020-04-21 |
| Incident number : | CZ-20-0190 |
| Report : | Final report |
| Place of event : | Hranice Airport |
| Registration mark : | Accident |
| Weight category MTOM: : | <2250 kg |
| Type of operation : | Recreational and sport aviation |
| Plane / SFM : | Airplanes |
| Type of plane / SFM : | Zlín Z-526 F |
| Health effects of event : | Without injury |
| PDF document : | 
|
Description:
Description:
On 21 April 2020, the ÚZPLN (Air Accidents Investigation Institute) was notified of the Zlín Z‑526 F aircraft accident at the Hranice Airport. The Zlín Z-526 F towing aircraft pilot was towing the L-13 glider. During the take-off, the towing aircraft's landing gear was retracted. The aircraft dropped and contacted the RWY 05 at LKHN. The glider pilot disconnected his glider in time and landed on the airfield. Only the towing aircraft was damaged during the accident. There was no third party injury or property damage. A patrol of the Police of the Czech Republic arrived at the aircraft accident scene and documented the towing aircraft's condition and accident site. Breath tests were performed with the towing aircraft crew to determine alcohol presence.
SUMMARY
Synopsis
On 21 April 2020, the ÚZPLN was notified of the Zlín Z-526 F aircraft accident at the Hranice Airport. The Zlín Z-526 F towing aircraft pilot was towing the L-13 glider. During the take-off, the towing aircraft's landing gear was retracted. The aircraft dropped and contacted the RWY 05 at LKHN. The glider pilot disconnected in time and landed on the airfield. A patrol of the Police of the Czech Republic arrived at the aircraft accident scene and documented the towing aircraft's condition and accident site.
Factual Information
The towing aircraft pilot and his instructor were completing aero-tow training at LKHN to earn his TOWING-S qualification per the DTO training programme. Before the critical flight, the Zlín Z-526 F pilot completed two aero-tows with the L-13 glider pilot. During the third aero-tow, upon the tow rope tensioning, the towing aircraft pilot increased the engine speed to its take-off mode. During the acceleration, after passing about 30 meters, when the glider was already flying after its take-off, the towing aircraft's landing gear got unloaded, retracted, and the towing aircraft dropped on the ground. During the drop, the propeller came into contact with the runway surface while the engine was running and the towing aircraft dropped on the ground. Shortly afterwards, the towing aircraft stopped. The crew remained uninjured. The towing aircraft was damaged to a large extent.
The towing aircraft pilot expressed his opinion on the accident: “After the second aero-tow landing, I turned off the engine and got out of the aircraft to pull the tow rope. Before the third aero-tow, due to my all-day fatigue and overall mental and physical burden (performing the entire training with a face mask), I accidentally switched the landing gear control switch to its "RETRACTED" position when performing my tasks after entering the cockpit.
Analyses
The pilot’s testimony and official records of the Police of the Czech Republic were used during the event investigation. No device whose recordings could be used for a flight analysis was installed in the aircraft. The towing aircraft pilot performed an aero-tow with the L-13 glider to earn his TOWING-S qualification per the DTO training programme with an instructor on board. On the day of the accident, it was his third aero-tow. When performing the "after entering the cockpit” tasks (Section 4.2 of the Flight Manual of the type), the pilot switched the landing gear control switch to the "RETRACTED" position. His performance was affected by his all-day fatigue and overall mental and physical burden when the entire training that day was carried out with the application of the anti-coronavirus measures (using face masks). When the landing gear control switch is in the "RETRACTED" position, due to the landing gear unloading after extending the shock absorber piston rod, the limit switch on the right landing gear leg closed. Upon closing, the electrical circuit connected, and the landing gear started its retraction through the electric strut with its continuous shaft.
Conclusions
The aircraft accident was caused by the pilot’s improper activity. After he entered the cockpit, the pilot accidentally switched the landing gear control switch to its “RETRACTED” position.
Safety Recommendations
No safety recommendation is issued.
Attached final report in PDF file is in original Czech language.