What happened
On February 17, 2015, a Sky Ranger ultralight aircraft, registration CS-UNV, was en route from Ponte de Sor (LPSO) to Alqueidão UL (LP0048) in Portugal. While cruising at 1,500 feet, the aircraft's engine began to operate irregularly before suffering a complete shutdown.
During the descent, the pilot and the aircraft owner—who was also on board as a passenger—discussed the situation and decided that the owner should take control of the aircraft for the landing, as he possessed more experience with this specific model. The pilot subsequently performed an emergency landing in a cork oak plantation. The aircraft touched down on soft ground at low speed and came to a halt within a few meters. Both occupants were uninjured, though the landing caused damage to the nose gear, the right main landing gear leg, and one propeller blade.
The investigation
The GPIAAF conducted a technical examination of the aircraft's systems to determine the cause of the engine failure. Investigators analyzed the fuel system, including fuel supply pressures and carburetor operation, finding no leaks or faults. The investigation also reviewed the aircraft's maintenance history and airworthiness status.
Findings
- The aircraft was powered by a Rotax 912 UL 80hp engine, which is a non-certified version intended for ultralight or experimental use.
- Maintenance records showed that the engine had undergone significant work just five days prior to the event, including the removal of the engine to repair ignition system coils, electrical terminals, wiring, and the generator stator cover.
- The aircraft's flight certificate had expired in July 2012, meaning the flight was not authorized under current airworthiness regulations.
- The aircraft was not equipped with a ballistic parachute recovery system.
- The engine shutdown was linked to recent maintenance performed on the ignition system and generator components.
- The investigation noted that national regulations for ultralight aircraft in the region were outdated and contained procedural gaps regarding standardization and pilot responsibilities.