What traits do they possess?
They make themselves visible by walking around and striking up conversations so that it'll make them approachable and amiable. By doing so people would be on good terms with them and would listen to them.
People want to know what to expect from you and if you are inconsistent, you wouldn't be reliable, then people would lose their trust in you.
Leaders initiate conversations to help find better solutions. Asking questions is a great way to initiate conversations. They accept suggestions from everyone.
Leaders influence other people with the tone they set and confidence. Confidence is contagious; so is the lack of it. People would mirror the tone they set and they encourage people.
Leaders accept challenges as well as successes. If an group member makes a mistake, it is their responsibility to help him or her improve. People will never respect a leader who deflects criticism toward the team. Leaders think of themselves as "we," not "I." It is a their responsibility to ensure that everyone shares in the team's success.
The most important characteristic of a leader is being a good listener. Leaders focus on the needs of their people. Often people feel afraid of, or intimidated by, management. Leaders make sure they show people you are willing to listen to what they have to say, that they are important and worthy of your time.
Most people care more about recognition from peers than about money. When somebody performs well, they let him or her know.
Leaders clearly convey their message in a way that connects with the listener. They understand that you tailor your message to the needs of each worker.
Leaders have fun in the process. There is no need to get very serious to do something well. Lightness can complement the seriousness of the job.
Example of a good leader:
Martin Luther King wanted equal rights for everyone as at that point of time, "black" people were discriminated by the "white" people. He wanted them to have freedom. He also made a speech "I had a dream" which was very inspirational.
[From general knowledge]
Source : http://www.asashop.org/autoinc/jan2005/manage.htm [I edited mine]
How do you think a good leader manages crisis under stressful situations?
A good leader would calmly handle the situation. He/she would analyse the situation and see what needs to be done, then he/she would finish whatever that has to be done. While doing so, He/she would help encourage those that are on the verge of giving up and he/she would say good things to help motivate the people so that they can handle the stress and continue doing their job, as moral support to his/her peers. By doing so, his/her peers would not feel as disheartened by all the stress and submit a lousy piece of work.
[My own answer]