Management is about following systems and processes and proceedures. Leadership is about changing them to achieve greater impact.
In a crisis, many weak leaders abdicate responsibility and behave like managers. Keeping their heads down, doing the minimum to stay out of trouble and blaming those above them for lack of direction, guidance and resources. Trouble is that crisis demands decisive, courageous leadership.
One of the first things that is needed in a crisis is to throw out or suspend beaurocratic management tools that may actually kill the organisation if religiously followed. You just don't have time for all that detail when big picture decisions are needed as a matter of great urgency eg a sweeping cut of 25% of the labour force.
It is absolutely vital to encourage each executive to rise above the chaos, keep engaged with the big picture, communicate closely with those above and below, make clear decisions in a transparent way with more regular meetings etc.
For more on practical steps to lead out of crisis back into growth see my article written yesterday on this: Article on main site