Covering form of preliminary or final report
| Date of event : | 2021-03-25 |
| Incident number : | CZ-21-0088 |
| Report : | Final report |
| Place of event : | Kladno airport |
| Registration mark : | Accident |
| Weight category MTOM: : | <2250 kg |
| Type of operation : | Recreational and sport aviation |
| Plane / SFM : | Helicopters |
| Type of plane / SFM : | GUIMBAL G2 CABRI |
| Health effects of event : | With injury |
| PDF document : | 
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Description:
SUMMARY
Synopsis
On 25 March 2021, the AAII was notified of an air accident of the GUIMBAL G2 CABRI helicopter at LKKL. The pilot with another person on board of the helicopter was carrying out a series of recreational flights. Having landed from a flight on the circuit, he continued in air-taxiing above the right edge of RWY 30. He planned to finish low-altitude manoeuvring with a left-hand braked turn into wind and a stop to hovering position. During this manoeuvre, a strong impact of the left skid of the main undercarriage into the ascending terrain occurred at the threshold of RWY 12. The main rotor blades then touched the terrain and the helicopter rolled over. The helicopter remained lying on the left side.
The pilot evacuated the injured female passenger from the helicopter cabin and then called for medical help by phone on [the Czech Republic] emergency line 155. The passenger was airlifted to hospital due to sustained serious injuries. The helicopter was completely destroyed after the contact of the rotating blade surfaces with the ground. The pilot was not hurt.
The Police of the Czech Republic, the FRS, and the AAII inspectors arrived at the location of the air accident and the AAII inspectors performed professional investigation of the location and the wreckage.
Factual Information
The pilot described the critical phase of the flight and the subsequent activity after the accident in his statement as follows: “I performed a short demonstration of hovering, flew around the circuit, and after landing I started the exercise at a low altitude above the runway, when I made turns between the side markings of Runway 30, and I was planning to end the exercise with a braked turn into wind and a stop to hovering position. I was anticipating an increased need for power during braking and transition to hovering, so I lifted the collective slightly at the beginning of the last turn. The helicopter, however, still began to descend in spite of the action taken. I recognised the need to intervene in the control and tried to save the situation by lifting the collective and levelling the helicopter to the horizon using cyclic control. However, I intervened either too late or insufficiently, or in a combination of both, and we crashed into the rising terrain at the threshold of Runway 12 with the front of the left skid. As a result of the impact to the ground, there was an uncontrollable tipping on the nose, the impact of the rotor into the ground, and we rolled over several times. I estimate the residual velocity at the moment of impact to be about 10 kt. After stopping of the movement on the left side, I asked (name of the passenger) if she was all right. She told me that she was not okay, that her leg was terribly sore. I turned off all the switches, unbuckled the passenger, unbuckled myself, got out of the helicopter, and pulled the passenger about 5–7 meters from the wreckage, where I then returned to close the main fuel valve. Using the passenger’s telephone, I called the emergency ambulance service. After the arrival of the ambulance and the FRS, the IRS unit and the airport operator took over the management of the site.”
Analyses
The critical situation occurred when the helicopter was moving at a relatively high forward speed along a curved flight trajectory in a left pitch against a slightly ascending terrain. First, the helicopter hit hard into the grassy airfield with the front of the left undercarriage skid. It pitched forward sharply and rolled to the left. The ends of the rotor blades got stuck into the turf. The helicopter flipped sideways across the bow around the vertical axis and crashed into the ground with its tail beam. The tail beam broke and the fuselage remained lying on the left side after hitting the ground.
Conclusions/Causes
The cause of the air accident was poorly managed piloting of the helicopter during the implementation of a braked turn at a low altitude. The contributing causes were little experience with type flying and manoeuvre performed against rising terrain.
Safety Recommendations
Given the circumstances of the air accident, the AAII issues no safety recommendations.
Attached final report in PDF file is in original Czech language.