Uruguay.FH-227 PLUNA · light that escorted the plane

On 25 September 1975, at 7:30 PM, a Fairchild FH-227 of the Uruguayan Air Force, on service for the state airline PLUNA, was covering the route between Asunción, Paraguay and Montevideo. It was flying at 14,000 feet (about 4,300 meters) and a cruise speed of 250 knots (around 450 km/h). Well into the night, after overflying the Monte Caseros area (on the border between Argentina and northern Uruguay, toward Artigas), the pilot noticed to his left and below, near the ground, a yellowish, almost white, very bright light that stood out against the night landscape.

The light did not stay on the ground: it began to ascend and, about five minutes later, had positioned itself at the aircraft's altitude, an estimated 3 to 5 miles away, from where it accompanied the uniform movement of the Uruguayan aircraft. To check whether the object reacted to a stimulus, the pilot made a deliberate decision: he turned on the aircraft's left landing light. He immediately observed the light approach significantly, a tendency that ceased (and reversed, the object returning to its previous position or size) when the pilot turned it off. This apparent correlation between the aircraft's light and the object's movement is the feature that has made the case famous, and also the hardest to assess, because a genuine interactive response and a temporal coincidence produce, from the cockpit, exactly the same impression. During the brief approach, the crew perceived a strong smell of burnt cable in the cabin, like that of an overheated electrical connection; however, checks of the systems found no fault to explain it, no smoke was seen and the smell disappeared within a few minutes. The captain called Area Control to report that he had an aircraft to his left and at his level; control replied that there was no reported air traffic on the route, at his level, or even in the area. Approaching Florida, the aircraft began to descend and went through clouds for the first time on the flight; the light kept accompanying it, but without descending, and at 6,000 feet, on entering the clouds, visual contact was lost for good. According to CRIDOVNI's officers, the two flight attendants and the captain's nephew watched the phenomenon from the cockpit, and many passengers corroborated it from their seats.

The nephew, who happened to be on board, was called to the cockpit and took two slide photographs which, according to the officers of the Uruguayan Air Force's CRIDOVNI (Commission for Receiving and Investigating Reports of Unidentified Flying Objects), were 'later examined by the official authorities'. It is worth placing the chronology precisely: the sighting predates the commission itself, which was created on 7 August 1979. The account in circulation is the one given to the press, decades later, by Colonel Ariel Sánchez Ríos and Lieutenant Enrique González of CRIDOVNI, who described it as one of the cases that most troubled the investigators; the result of that examination has not been published.

The 'interactivity' (the light approaching when the landing light is turned on and withdrawing when it is turned off) is the most suggestive feature, but also the most fragile: with a single recorded on-off cycle, a coincidence between the pilot's maneuver and an object that was oscillating in distance anyway produces exactly the same impression as a deliberate response, with no way to tell one from the other from the cockpit. The smell of burnt cable with no electrical fault found is striking, but smells have many mundane causes, and the absence of a found fault is not equivalent to the presence of an exotic cause. No radar confirmation or material recovery is on record; what is on record is that Area Control had no reported traffic in the area.

And there is a concrete candidate. Juan Carlos Victorio, author of the Misterios del Aire blog, who examined the account, the surveys of the observers and the slides, proposed in 2014 that the light was the planet Jupiter, at its brightest because of its opposition on 13 October: at the start it lay to the aircraft's left, toward the east and very close to the horizon, exactly where the pilot saw the light 'apparently near or on the surface of the earth', and it rose steadily during the hour and a half of the observation. According to him, the slides show only 'a tiny dot' and, in one, an irregular trail from camera movement, typical of photographing a bright planet by hand. An ephemeris calculation for that night supports the essentials: seen from 14,000 feet over Monte Caseros, Jupiter, at magnitude −2.8, cleared the east-northeast horizon (azimuth about 83°) at about 20:05 Uruguayan time and stood about 20° high by about 22:00, always to the left of a heading toward Montevideo; and an astronomical light does not descend when the aircraft descends either, which is what the light did over Florida. The timing fits as well: CRIDOVNI's account places the aircraft in flight 'siendo las 19,30 hs.' and the sighting later, 'después de sobrevolar Monte Caseros y siendo ya noche profunda', that is, when Jupiter had already risen or was rising. What remains against it is that the hypothesis's only source is a blog, and that the light's rise to the aircraft's level in five minutes, the apparent response to the landing light and the smell in the cabin are elements the hypothesis does not explain by itself, although the first two are consistent with perceptual illusions known among pilots. CRIDOVNI's officers still cite it among the cases that most troubled their investigators.

In Uruguay the commission worked alongside civilian researchers such as Milton Hourcade, founder of CIOVI (1958).