What happened
On the evening of August 15, 2000, a two-seat Dynali Chicknox Tandem ultralight, registered as EC-18, was conducting local VFR flights near Monte Gordo, Portugal. The aircraft, which had been purchased in Spain only five days prior to the accident, took off from an unidentified private airstrip at approximately 18:45 UTC.
Roughly ten minutes into the flight, witnesses observed the aircraft flying at a low altitude, estimated between 50 and 60 meters, over the Esteiro da Carrasqueira salt marsh. Observers reported seeing the aircraft's wings suddenly move into a vertical position, striking one another, while the engine continued to run. Following this impact, the aircraft lost all forward progress, entered a rolling descent, and crashed into the marsh, where it became partially submerged and was destroyed.
The investigation
The investigation focused on the structural integrity of the aircraft and the flight conditions. Investigators noted that the EC-18 was operating without a Spanish flight certificate or valid insurance for operations in Portugal. While the aircraft was a kit-built model from the Belgian manufacturer Dynali, the investigators could not verify its airworthiness or maintenance history due to the lack of identifiable serial numbers on the airframe and engine.
Witness accounts strongly suggested a sudden structural failure. Although specific laboratory tests on the wing structure were not available to the investigators, the visual evidence of the wings colliding mid-air pointed toward a catastrophic loss of structural integrity. Additionally, the pilot, while a student commercial pilot with significant training hours, did not hold a valid ultralight pilot license.
Findings
- The primary cause of the accident was a structural failure of the aircraft wings, resulting in a collapse likely caused by aerodynamic loads exceeding the design limits.
- The aircraft was flying at an altitude of 50 to 60 meters, which was below the recommended safety altitude of 100 meters.
- There was a possibility that deficient maintenance contributed to the structural failure.
- The aircraft lacked proper registration documentation and valid insurance for the region.
Safety action
- The aeronautical authority was advised to review the operating conditions for non-Portuguese registered ultralight aircraft operating within national airspace.
- A recommendation was made to implement mandatory maintenance programs for ultralight aircraft, following manufacturer technical manuals.
- The authority was urged to update and formalize operating regulations for ultralight aircraft within the Faro Airport exclusion zone.