What happened
On February 10, 2008, a privately operated Moravan Zlin 526 F departed from Etampes Aerodrome for a local flight. Shortly after takeoff, while climbing through approximately 500 feet, the left engine cowling opened. Following the incident, the pilot performed an airfield circuit and declared an immediate intention to land on the unpaved runway 06. The aircraft landed at 15:35 with the landing gear still in the retracted position. The impact caused damage to the propeller and the lower engine cowling.
The investigation
The investigation focused on the sequence of events leading to the unsecured cowling and the subsequent failure to extend the landing gear. The pilot reported that during the pre-flight inspection, which was conducted in a hangar in a non-standard order due to the presence of visitors, the engine cowlings had been opened. The pilot failed to verify that the left cowling was properly locked before departure.
Regarding the landing, the investigation established that the pilot became preoccupied with the consequences of the cowling opening during the climb. This distraction led to a shortened circuit and the omission of the landing gear extension. While the aircraft was equipped with several indicators—including green lights, visual red-and-white gear struts, and an audible warning alarm that activates when the power lever is at idle—the pilot did not extend the gear or verify its status on final approach. Although the pilot stated he did not hear the audible alarm, technical examinations confirmed that the warning system was fully functional.