Incident Overview
During the approach and landing phase, the pilot-in-command selected the 40-degree flap position. On short final, the airplane experienced a sudden loss of lift, described as 'falling out of the sky.' After landing and exiting the aircraft, the pilot observed that the flap handle was in the 30-degree position, contrary to his selection.
Post-Landing Inspection
Following the incident, an examination of the flap system was conducted. The inspection revealed that the flap handle would not remain in the 40-degree selected position if it was bumped. Furthermore, when moving the handle from the 30-degree to the 40-degree position, it was noted to be very stiff and would not completely latch into the 40-degree detent.
Flap System Examination
A detailed examination of the flap system showed that the handle had a mechanical deficiency. The stiffness and incomplete latching at the 40-degree position prevented the handle from staying securely in place. This condition could allow the handle to inadvertently move from the selected 40-degree position to a lower setting, such as 30 degrees, potentially affecting lift during landing.