[MER] LAT 44.76, LON -4.32 (INT) 03.07.1990

GEIPAN continues to publish all its archives on its public website, www.geipan.fr. These publications include older cases, classified at the time as A, B, C or D, that are now being reexamined solely to improve the relevance of their conclusions. New technical tools (software) and the investigative experience gained over the years sometimes lead this reexamination to new observations or even a change of classification. This sighting, previously classified D and named [MER] LAT 44.76, LON -4.32 (INT) 03.07.1990, is among the cases recently reexamined. On 3 July 1990 at about 22:30, a witness at the helm of his sailboat off the Spanish coast observed a UAP for slightly more than 30 seconds. It was a luminous oval object with a red light on one side and a green-blue light on the other. No particular sound or disturbance aboard was noticed; the boat's engine was running and its navigation lights were operating. He went to the gendarmerie station on 20 July 1990. He very probably observed an aircraft preparing to land at night at a Spanish airport with its landing lights on (see investigation report). The reported red, blue-green and white or yellowish-white lights are characteristic of an aircraft misidentification. The red and green, perceived as blue-green, lights are navigation lights. An airplane is more likely than a helicopter: the main light, bright “like a bulb” and forming a horizontal oval, could match 2 closely spaced, horizontally aligned airliner landing lights viewed from a distance. The viewing distance must be considered in relation to seeing several types of lights together despite their differing power and range. The red and green navigation lights clearly seen by the witness have much shorter range than landing lights and white anti-collision lights. The latter's distinctive flashing is visible from far away, but the witness never reported it. The source states that international aviation regulations require navigation lights in all circumstances, whereas anti-collision lights may be switched off in particular conditions such as fog, very heavy rain or passage through cloud during an IMC flight, when reflections from suspended water droplets could disturb the pilot. An aircraft a few kilometers away seems more likely than one roughly 100 km away, where its navigation lights would be invisible. The missing anti-collision lights would therefore have to be attributed to weather warranting temporary switch-off, conditions that can no longer be confirmed or disproved. Although the landing lights appear to have been on well before landing, under the coastal Spanish airport hypothesis, they can also be used in other circumstances that may apply here: congested airspace, low altitude or a change in flight level. Landing lights have limited horizontal and vertical coverage, explaining why the witness did not see them illuminate the ocean. Their beams need not be visible, depending on suspended atmospheric particles between the witness and the UAP. The maneuvers reconstructed from the account, including circuits and turns, fit an airliner approaching an airport, although they would have occurred far from the Spanish coast. Traffic records to strengthen or disprove this hypothesis are unavailable 30 years later. Finally, the lack of perceived sound is not decisive. The boat's engine could have masked aircraft engine noise, which might also have been reduced by wind opposing its propagation. Substantiation is weak, with little usable information, but sufficient to validate the hypothesis given its high probability. GEIPAN therefore classifies the case A: very probable observation of an airplane.