What happened
On April 2, 2017, a Moragon UL2, registration EC-ZEP, departed from Sabadelle Airport for a local flight with a pilot and one passenger. While flying near Cardedeu, the pilot reported hearing an intermittent noise before the engine failed completely. The aircraft entered a steep descent of approximately 1,000 to 1,500 feet per minute.
Facing a mountainous area to the left and an industrial park to the right, the pilot declared a 'MAYDAY' and identified the AP-7 motorway as a potential landing site. To ensure visibility to motorists, the pilot flew at a very low altitude—approximately 4 to 5 meters—directly over the highway lanes before touchdown. The aircraft landed in the central lane at kilometer marker 122 near Llinars del Vallès. Following the landing, the pilot successfully restarted the engine and taxied the aircraft to a nearby rest area under escort by local police.
The investigation
The investigation examined the aircraft's maintenance history, engine condition, and the pilot's actions. It was noted that the aircraft had changed ownership only 14 days prior to the incident, and no specific inspection had been performed following the transfer of title. Additionally, the aircraft's certificate of airworthiness had expired, as the renewal process was still pending with the authorities.
Technical inspections of the engine revealed several mechanical issues. Investigators found that the engine was operating with critically low oil levels and that the spark plugs were in poor condition, with several cylinders showing no spark at all. Furthermore, the engine was being operated using 95 octane gasoline instead of the manufacturer-recommended AVGAS 100LL. While the use of lower-octane fuel was not identified as the direct cause of the shutdown, the overall state of the engine pointed toward significant maintenance deficiencies.
Findings
- The investigation could not pinpoint a single definitive cause for the engine failure, but identified inadequate maintenance as a primary contributing factor.
- Significant mechanical deficiencies were present, including poor cylinder compression, a faulty ignition system, and insufficient engine lubrication.
- The aircraft was flying with an expired certificate of airworthiness.
- The pilot's emergency landing was made safer by low traffic density and the pilot's decision to fly over the lanes to alert drivers.