Is there a neutral relationship between 'By 8:33, it had reached its assigned cruising altitude of 31,000 feet.' and 'By 8:33, it hadn't climbed to above 20,000 feet.', lacking direct logical ties?
By 8:33, it had reached its assigned cruising altitude of 31,000 feet.###By 8:33, it hadn't climbed to above 20,000 feet.