My observation is that it's relatively easy (not actually easy though!) to appear to be a good manager when things are going well. And that can last long enoug

My observation is that it's relatively easy (not actually easy though!) to appear to be a good manager when things are going well. And that can last long enough for someone to be promoted several times. But it's hard to tell whether someone is _actually_ a good manager until you've observed their reactions in times of stress. If they've reached senior levels already then it probably doesn't matter whether the managers under them are any good or not: it's not going to go well.