1:34 p.m. local. Carlos Antonio de los Santos Montiel, 23, was flying a Piper PA-24 from Zihuatenejo to Mexico City at about 15,000 feet (4.5 km). While passing over Lake Tequesquitengo, he felt a strange vibration in the plane. Then he saw to the right, pacing alongside, a 10-to 12-foot (3 meters) in diameter disc with a dome on top. Another appeared to the left of the plane, and a third disc appreached head-on, dropping beneath the plane. Carlos felt a jolt as if the object had collided with his plane. He pulled the landing gear lever, but it failed to operate. The plane felt as if it were being pulled or lifted, and the controls refused to re*spond. Although badly shaken, Carlos notified Mexico City by radio, describing what was happening. At the same time air control radar was showing unexplained objects near his plane that were capable of sharp turns, unlike normal aircraft. Finally their blips merged on the radar screen and sped away toward Mt. Popocatepetl. After the objects left, Montiel was able to lower his landing gear manually and to land safely. Aviation personnel who know him testified to his sobriety and trustworthiness