Covering form of preliminary or final report
Back| Date of event: | 2025.03.02 |
|---|---|
| Incident number: | CZ-25-0216 |
| Report: | Final report |
| Place of event: | LKCB |
| Registration mark: | Air accident |
| Weight category MTOM:: | <2250 kg |
| Type of operation: | Recreational and sport aviation |
| Plane / SFM: | Sports flying machine |
| Type of plane / SFM: | EV-97 Eurostar SL |
| Health effects of event: | The fatal injuries |
| PDF document: |
 |
Description:
SUMMARY
Synopsis
On 2 March 2025, the AAII was notified of an air accident of UL aircraft, the EV-97 Eurostar SL, registration mark OK-SUR 88, which had crashed in a field near the Dřenice sand quarry on the eastern edge of Cheb Airport. The pilot was carrying out training flights on the circuit. After taking off from RWY 05, the aircraft continued on a left-hand circuit and then performed a touch-and-go landing and take-off from RWY 05, climbing steadily in the direction of the runway. At the altitude of approximately 100 m above the ground, there was a sudden change in flight path and the UL aircraft crashed into the ground at a steep angle, approximately 700 m north-east of the threshold marks of LKCB RWY 23. It was completely destroyed when it hit the ground. The pilot succumbed to his injuries at the accident site.
Factual information
Circumstances preceding the critical flight
The pilot collected the aircraft keys from the aeroclub office and, shortly after 14:00, took the UL aircraft out of the hangar and began conducting a pre-flight inspection. Once finished, he boarded the cockpit of the UL aircraft. After starting the engine, the pilot taxied from the hangar to the holding position on RWY 06, where he carried out an engine test. After taking off from RWY 05, he continued his flight on a left-hand circuit, focusing on a noise abatement approach, followed by a touch-and-go landing on the grass RWY 05.
The critical phase of the flight occurred shortly after take-off, whilst the UL aircraft was climbing on the runway heading. At approximately 100 m AGL, there was a sudden change in the flight path. The UL aircraft significantly increased its pitch, followed by a right roll and a transition into a steep descent. The UL aircraft crashed into the ground at a steep angle approximately 700 metres north-east of the threshold marks of LKCB RWY 23.
Situation before the critical flight
The pilot took off from the grass RWY 05 and continued as planned, flying on a left-hand circuit around the runway whilst adhering to the noise abatement procedure. During the flight, he was reporting the required positions on the circuit. The reports were standard and contained no information about problems with the folding canopy.
During a touch-and-go landing and take-off, the single-position lock became disengaged from its locked position either upon initial contact or whilst the UL aircraft was moving along the grass runway. From that moment on, the canopy frame was no longer mechanically secured to the UL aircraft’s cockpit frame.
The critical situation is thought to have arisen only after take-off, during the climb phase, when aerodynamic forces caused the folding canopy to open spontaneously. The open canopy caused a significant deterioration in flight characteristics and, for the pilot – who was probably not fully familiar with this problem and had not encountered it before – it was a major source of stress. The pilot probably attempted to close the canopy again because he was acutely aware of the significant risk posed by the open canopy potentially being torn off. Given the limited range of movement of his upper limbs within the cockpit, with his body secured by seatbelts in the pilot’s seat, he probably deliberately unfastened them. Whilst handling the cockpit canopy, he did not devote his full attention to flying the aircraft, which could have been adversely affected at this stage of the flight by wake behind the open canopy. Wake causes vibrations in the horizontal tail units; in extreme cases, this may lead to a loss of longitudinal stability. This adversely affected the manoeuvrability of the UL aircraft, which, whilst climbing at an altitude estimated by casual witnesses to be approximately 100 metres above the ground, suddenly went into an uncontrolled dive with a slight drift to the right. On the steep descent, loose items were falling out of the open cockpit. These items were found on the ground in the area behind the UL aircraft wreckage. Due to the deformation of the folding canopy caused by aerodynamic loads, the pilot was unable to close it completely and secure it with the lock. Given the aircraft’s altitude, the pilot had no chance of recovering from the UL aircraft’s crash, as the elevator was in what is known as the ‘aerodynamic shading’ and did not respond to the pilot’s attempts to control it. The UL aircraft crashed into the ground at a steep angle, and the pilot was thrown from the cockpit by inertial forces at the moment of impact. The impact of the body against the open canopy caused the organic glass of the canopy to shatter and the upper part of the composite frame of the canopy with a single-position lock to break off. The individual parts that were shattered on impact when the UL aircraft struck the ground, which had become detached from the aircraft, were found, together with the pilot’s body, in the area in front of the UL aircraft wreckage.
Conclusions/causes
· Held the valid VFR licence and was medically fit for performing the flight;
· Did not have any identified health problems that could contribute to the occurrence of the emergency situation;
· Had sufficient flying experience, but had flown relatively few hours on that particular aircraft type;
· Took off without a Flight Manual on board;
· Did not report any fault or malfunction over the radio during the first circuit;
· Following the spontaneous opening of the folding canopy, he did not follow the procedure set out in the Flight Manual (the Commission was unable to determine whether the Flight Manual contained the required procedure);
· In an attempt to prevent the open folding canopy from coming loose, he probably tried to close it again;
· Whilst making a futile attempt to close the folding canopy, he did not devote his full attention to flying the aircraft;
· Was unable to recover the subsequent crash, given the altitude of the flight and the reduced longitudinal manoeuvrability of the UL aircraft caused by the wake behind the open canopy;
· Was thrown out of the cockpit by the inertial forces, when the UL aircraft crashed into the ground;
· Succumbed to his injuries at the accident site.
· Had a technical certificate valid until 1 September 2025;
· Had a valid liability insurance;
· Was filled with the required amount of all working fluids;
· Its weight was within the prescribed limits;
· Was operated in breach of Mandatory Service Bulletin No. EV97-027a SR issued by the manufacturer on 16 June 2014, because the single-position lock on the fibreglass folding canopy frame had not been replaced with a two-position lock;
· Was not airworthy, due to the absence of a Flight Manual on board during the flight;
· During the first circuit, the pilot did not report any defect or fault nor any other type of aircraft malfunction;
· The cockpit canopy opened spontaneously during the second flight, whilst climbing following a touch-and-go landing and take-off;
· The open folding canopy allowed loose objects to fall out of the cockpit;
· The open folding canopy had a significant negative impact on the flight characteristics of the UL aircraft;
· Was destroyed by the forces of the impact with the ground;
· Upon investigation at the place of air accident and subsequent technical investigation of the UL aircraft wreckage in the AAII hangar, no facts that would indicate that the air accident had been caused by a technical defect were detected.
· According to the expert examination, the engine was fault-free and operated normally throughout the critical flight.
· Following an inspection of the accident site and the wreckage, the Commission found out that the aircraft struck the ground at a steep angle and with a high vertical rate of descent, leaving the pilot with no chance of survival.
· Did not have a negative impact on the course of the flight or the development of the critical situation.
· The owner/operator operated the aircraft as unairworthy for more than 10 years and lent it out for use whilst it was in that condition.
The cause of the aircraft accident was the sudden, uncontrolled opening of the folding canopy during the climb phase following take-off, when the pilot, whilst attempting to close the canopy, lost control of the aircraft, which, having lost speed, went into a dive and crashed into the ground at a steep angle.
Safety Recommendation CZ-26-0008
Based on the Commission’s finding that it is not possible to verify retrospectively the validity of information regarding the condition of the SFD, as set out in a verbal agreement when the aircraft was loaned, the Air Accidents Investigation Institute recommends that the Light Aircraft Association of the Czech Republic draw its members’ attention to this issue in an appropriate manner and prepare a simple form for a Lease Agreement, or Agreement on the Provision of SFD for Training and Flying. Under such Agreement, the aircraft owner/operator would, amongst other things, be required to expressly declare that the SFD is being handed over in a fully airworthy condition and complies with all Mandatory Service Bulletins issued by the manufacturer and the Light Aircraft Association of the Czech Republic.
Safety Recommendation CZ-26-0009
Based on the Commission’s finding that the UL aircraft with registration mark OK-SUR 88 had been in operation for more than 10 years without implementing the Mandatory Service Bulletin, yet its technical certificate was still valid until 1 September 2025, the Air Accidents Investigation Institute recommends that the Light Aircraft Association of the Czech Republic consider reviewing its current procedures for extending airworthiness.
Attached final report in PDF file is in original Czech language.