Covering form of preliminary or final report
Back| Date of event: | 2024.05.13 |
|---|---|
| Incident number: | CZ-24-0430 |
| Report: | Final report |
| Place of event: | 1 km north of the village of Luka nad Jihlavou |
| 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: | JA 600 (Skyleader 600) |
| Health effects of event: | The fatal injuries |
| PDF document: |
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Description:
Summary:
On 13 May 2024, the AAII was notified of an air accident of a JA-600 UL aircraft (Skyleader 600), registration mark OM-M267, in a forest opening about 1 km north of the village of Luka nad Jihlavou. The pilot, a foreign national, was conducting a flyover of his own UL aircraft from Jihlava to Trnava after a 25-hour service inspection by the manufacturer.
After take-off from RWY 10 at LKJI, the pilot was climbing steadily approximately on the runway heading. At 3,000 ft MSL, he brought the UL aircraft to level flight and engaged the autopilot. After 30 sec of horizontal flight, there was a sudden abrupt change in the flight trajectory in both the horizontal and vertical planes.
The UL aircraft went into an extremely sharp descent, hit the ground in the inverted attitude at a steep angle and started to burn. It was completely destroyed by the impact with the ground and the subsequent fire. The pilot succumbed to his injuries at the accident site.
Various IRS units intervened at the accident site. On the same day, an AAII inspector arrived at the accident site and together with a forensic physician and the Police of the Czech Republic carried out a professional investigation.
Synopsis
On 13 May 2024, the AAII was notified of an air accident of a JA-600 UL aircraft (Skyleader 600), registration OM-M267, in a forest clearing about 1 km north of the village of Luka nad Jihlavou. The pilot, a foreign national, was conducting a flyover of his own UL aircraft from Jihlava to Trnava after a 25-hour service inspection by the manufacturer.
After take-off from RWY 10 at LKJI, the pilot was climbing steadily approximately on the runway heading. At 3,000 ft MSL, he brought the UL aircraft to level flight and engaged the autopilot. After 30 sec of horizontal flight, there was a sudden abrupt change in the flight trajectory in both the horizontal and vertical planes.
The UL aircraft went into an extremely sharp descent, hit the ground in the inverted attitude at a steep angle and started to burn. It was completely destroyed by the impact with the ground and the subsequent fire. The pilot succumbed to his injuries at the accident site.
The pilot set the atmospheric air pressure on the barometric altimeter to 1,019 hPa. After take-off from RWY 10 at LKJI at 13:12:00, the UL aircraft was climbing steadily on the runway heading to ALT 3,000 ft and maintained IAS of 97 kt. The power unit operated at RPM of 5,700 rpm and MAP of 25.6 inch∙Hg. In this mode, having reached ALT of 3,084 ft with trim at minus 8° at 13:14:48, the pilot engaged the autopilot in LVL mode. Within 6 seconds of engaging the autopilot, the pilot reduced MAP from 25.6 to 15.7 inch∙Hg and RPM stabilised at 5,800. The MAP and RPM values remained the same during the 30-second flight with the autopilot engaged. Trim gradually moved from minus 8° to minus 18° and IAS gradually decreased from 96.8 to 80.2 kt. During the last 2 seconds, the autopilot responded to the decrease in airspeed by changing the UL aircraft pitch from plus 4° to minus 8°. The pilot used the trim control button on the control lever to disengage the autopilot (manual trim command) and within one second the aircraft pitch changed from minus 8° to plus 18°. During the flight with the autopilot off, the trim position changed from minus 24° to plus 19°. The UL aircraft abruptly changed pitch from level flight to a 76° dive during a 15-second manual control and went from a flat bank to a right bank and then to an inverted dive. At 13:15:36, at 400 ft AGL, at a vertical descent rate of 9,000 ft∙min-1, the data recording was terminated. Throughout the flight, the Garmin G3X EFIS screen displayed the warning message CANOPY OPEN. The AP activity information was displayed in green and the system showed no deviation from normal.
The pilot was not under the influence of alcohol or any other substances prohibited for aviation duty, but was adversely affected by inhalation of air containing carbon monoxide, which could have caused, for example, headache, discomfort or restlessness. These symptoms, combined with possible fatigue and little experience with flying on the type, could have led to pilot’s loss of attention and errors listed below during the critical flight:
1. He closed the cockpit canopy incorrectly, which was indicated on the Garmin G3X EFIS screen throughout the flight, but he did not respond.
2. He engaged the AP in LVL mode, but only after that he reduced the engine power.
3. After engaging the AP, he probably started to solve the problem with the improperly closed cabin and did not pay full attention to the control of the UL aircraft.
4. He set engine power incorrectly when flying with autopilot engaged in LVL mode, but did not respond to the gradually decreasing airspeed.
5. He probably unconsciously interfered with the control of the aircraft in the AP mode, which he switched off incorrectly with the trim button on the control lever (manual trim command).
6. He failed to make the transition to manual control of the UL aircraft in ground mechanical turbulence conditions and subsequently lost control of the aircraft.
The pilot was conscious during the flight, but his little experience with flying in general, but also on the specific type of UL aircraft, may have also contributed to the high workload, reduced situational awareness and negatively influenced decision making under stress to the extent that he did not activate the parachute ballistic rescue system as a last resort to save his life.
Upon investigation at the air accident site and subsequent technical investigation of the UL aircraft wreckage in a specialised AAII unit, no facts that would indicate that the air accident had been caused by a technical defect have been detected.
The critical situation occurred when the RPM was at the required value for cruise mode and the MAP of 25.6 inch∙Hg corresponded to take-off mode. The pilot engaged the autopilot in LVL mode and subsequently reduced MAP to 15.7 inch∙Hg. However, this value did not correspond to the required engine power for horizontal flight in cruise mode. The MAP and RPM values remained the same during the 30-second flight with the autopilot engaged. The autopilot, engaged in zero vertical speed mode, responded to the situation by gradually reducing speed to maintain zero vertical speed. As the pilot did not react to the gradual loss of speed by increasing engine power, the IAS reached the value of 80.2 kt 29 seconds after autopilot engaging. During the last 2 seconds, the autopilot responded to the decrease in airspeed by changing the UL aircraft pitch from plus 4° to minus 8°. The pilot reacted to the unexpected nose drop by pulling the control lever, because within one second the aircraft pitch changed from minus 8° to plus 18°, and probably by mistake, by using the trim control button on the control lever, he switched off the autopilot (manual trim command).
During the flight with the autopilot off, the trim position changed from minus 24° to plus 19° during uncoordinated interference with controls. The UL aircraft abruptly changed pitch from level flight to a 76° dive during a 18-second manual control and went from a flat bank to a right bank and then to an inverted dive. At 13:15:36, at 400 ft AGL, at a vertical descent rate of 9,000 ft∙min-1, the data recording was terminated. After another 2 seconds, the UL aircraft hit the ground in the inverted attitude at a vertical descent rate of less than 50 m∙sec-1 .
The wind direction and speed, which reached up to 30 kt at an altitude of about 400 m AGL, affected the formation of ground mechanical turbulence with a possible negative effect on the piloting of the UL aircraft.
The cause of the air accident was an incorrect procedure of autopilot activation with subsequent uncontrolled piloting of the UL aircraft after its accidental shutdown during flight in turbulent conditions and failure to activate the fully functional ballistic parachute rescue system.
In view of the finding that already during a 5-minute flight, when the pilot inhaled air polluted with exhaust gases, the carboxyhaemoglobin saturation of pilot’s body reached up to 15%, the Air Accidents Investigation Institute recommends the manufacturer of the UL aircraft to implement the following safety recommendation.
Safety Recommendation CZ-25-0009
Given the circumstances of the air accident, the Air Accidents Investigation Institute recommends the manufacturer to install mandatory visual and acoustic indication of the presence of excess carbon monoxide in the cabin in all newly manufactured UL aircraft, type JA-600 (Skyleader 600), and to consider the possibility of installing the system in the already manufactured ones by way of bulletin.
Attached final report in PDF file is in original Czech language.