What happened
On January 3, 2016, a pilot was performing circuit training at Kamp-Lintfort Airfield (EDLC). After completing an initial circuit, the pilot executed a touch-and-go landing on runway 25. During the subsequent initial climb, the pilot reported engine problems and turned right toward the north, approximately 150 meters past the western airfield boundary.
Following the radio transmission, the air traffic controller advised the pilot to establish a glide attitude. Witnesses observed the HK 3/6 R Super Dimona flying very slowly and without gaining altitude. GPS data indicated the aircraft was at an altitude of approximately 70 meters. After flying roughly 500 meters, the aircraft rolled onto its right wing and impacted the ground in a nose-down attitude. The pilot sustained fatal injuries, and the aircraft was destroyed.
The investigation
The BFU investigation focused on the sequence of events leading to the loss of power and the pilot's subsequent actions. Investigators examined the aircraft's propeller control system and found that the locking mechanism for the propeller pitch toggle switch was defective. This defect allowed the switch to be moved from the 'Auto' position to the 'Feather' (gliding) position unintentionally.
Evidence suggested that while preparing for the touch-and-go, the pilot likely accidentally moved the defective switch. Because the electric propeller regulator requires 60 to 90 seconds to transition from climb to feather mode, the resulting loss of engine performance was gradual and initially unnoticed. The investigation also noted that the pilot had not flown for approximately three months and had limited recent experience in this specific aircraft type.
Findings
- The primary cause of the accident was a gradual loss of climb performance caused by the unintentional movement of the propeller pitch switch into the feather position.
- The pilot failed to maintain sufficient airspeed, leading to an uncontrolled flight state and the subsequent stall/roll.
- The pilot's situational awareness was compromised; rather than maintaining control and heading toward available emergency landing fields, the pilot followed the controller's suggestion to establish a glide attitude, which involved shutting down the engine.
- Contributing factors included the pilot's lack of recent flight currency and organizational deficiencies within the flying club regarding the identification and reporting of safety-critical equipment malfunctions.