A good leader has to be able to influence others and make them willingly want to do what the leader wants them to do. Without influence, nobody would be following the leader and the leader would have a hard time making their followers do what he wants them to do.
A good leader must also be honest in their deeds and words. If a leader is not honest, their followers will, sooner or later, lose trust in them. Without their followers' trust, they will also lose their influence and it would be extremely hard for him to gain it back.
A good leader has to set a vision for their followers, so that they all have one common goal and know what they are working for.
How do you think a good leader manages crisis under stressful conditions?
I think a good leader would keep his calm and think through the situation first. He will then consider the options given to him and select the best option to solve the crisis.