DIARIO DE BURGOS: 30 DE MARZO DE 1950
The sighting was on March 29, 1950 at 12:15 am, exactly. At the airport was the chief commander of sector Villafria (BURGOS-SPAIN) Esteban Ibarreche and Captain Don Salvador Hedilla Ruiz Gómez, head of the weather service, accompanied by teletype service manager Don Francisco Bescós Mombrano Sgt transmissions. They heard a noise similar to that produced by the passage of a plane at a considerable height. Captain Ruiz Gomez told reporters: "... the flying wing produced a perceptible buzz though much smaller than the noise of the aircraft.
"The vision lasted three minutes and the engine, after declining significantly in speed, disappeared in the horizon, going into the clouds, heading south-southwest.
"Look, I clocked the time it takes to discover the binoculars, it took exactly 35 seconds, well, in that short period of time, or until I locate, moved about 10 km which, according to calculations made with the Head of Sector commander of the airfield, Mr. Ibarreche, suggests it would take a speed of 700 to 1000 km per hour.
I insist that all these data are not strictly accurate, but relative. "JAC