What happened
On April 22, 2006, a Cessna 172N, registration PH-THS, was performing an advertising banner tow flight over the Stadskanaal area. The aircraft was flying a circular pattern at approximately 1,000 feet, towing a large banner. Simultaneously, a Comco Ikarus C42B microlight aircraft, registration PH-3X9, was conducting a local flight in the same vicinity.
During the flight, the pilot of the Cessna 172N experienced a sudden loss of resistance, indicating that the banner had become detached. The microlight aircraft, which was flying at a lower altitude, struck the towing cable or its anchor. The impact caused significant damage to the right wing of the Comco Ikarus C42B, leading to a loss of control and a subsequent stall. The microlight crashed into a residential neighborhood, where it caught fire. The collision resulted in one fatality (the pilot of the microlight) and damage to several houses and vehicles on the ground. The pilot of the Cessna 172N was able to land safely back at Groningen Airport Eelde.
The investigation
The Dutch Safety Board (OVV) examined the wreckage, radar data, and witness testimonies. Technical analysis of the Comco Ikarus C42B showed no prior mechanical failures, and an autopsy confirmed no impairment of the pilot's physical or mental state. Investigators found paint traces on the microlight's right wing that matched the paint on the banner's anchor.
Radar data revealed that the Cessna 172N was flying at an altitude of approximately 1,000 feet, which was below the required minimum of 1,394 feet for advertising banner flights in that region. The investigation also looked into the visibility from the cockpit of the towing aircraft, noting that the pilot's position on the left side of the cockpit could limit the view of aircraft approaching from the lower right.
Findings
- The primary cause of the accident was the failure of the see-and-avoid principle.
- The pilot of the Comco Ikarus C42B likely failed to notice the towing cable and its anchor, which are difficult to see due to their low position relative to the aircraft.
- The Cessna 172N was operating at an altitude lower than the regulatory minimum for advertising banner operations.
- The collision with the cable caused structural damage to the microlight's wing, initiating the fatal stall.