In relation to 'At 8:51, the flight deviated from its assigned altitude, and a minute later New York air traffic controllers began repeatedly and unsuccessfully trying to contact it.', does 'At 8:51 the flight descended from its altitude.' express a contradictory stance?
At 8:51, the flight deviated from its assigned altitude, and a minute later New York air traffic controllers began repeatedly and unsuccessfully trying to contact it.###At 8:51 the flight descended from its altitude.