What happened
On May 1, 2003, a Jabiru SK ultralight aircraft, registration CS-UJB, departed from the Lagos Municipal Aerodrome in Portugal. Shortly after takeoff, the pilot noticed that the engine cover had opened during flight. In an attempt to return to the runway, the pilot initiated a left-hand turn.
During the turn toward the final approach, the aircraft entered a stall and began a descending spiral to the right. The aircraft struck the ground near a residential area, resulting in two fatalities. The pilot sustained traumatic injuries and passed away five days after the accident, while the passenger died instantly upon impact.
The investigation
The GPIAAF investigation focused on the mechanical state of the engine cover and the flight dynamics during the stall. Investigators examined the wreckage and found that the engine cover had shifted forward and upward, striking the propeller. This impact limited the pilot's ability to use full engine power.
Physical evidence showed that while the safety pins were in place, the right-side latch of the engine cover was not properly engaged with its hook. The investigation noted that the grey color of the latches and hooks made it difficult to visually confirm if they were correctly seated. Furthermore, the investigation found that it is possible to install the safety pin even when the latch is not properly hooked into position.
Findings
- The primary cause of the accident was the loss of control of the aircraft during the turn to final approach.
- A contributing factor was the opening of the engine cover in flight due to the improper use of the right-side safety latch.
- The pilot was flying at a low altitude and near stall speed with reduced power, which led to the aircraft entering a descending spiral when the turn was tightened.
- The engine cover's displacement caused damage to the propeller, restricting power availability during a critical phase of flight.