Today, Im flying as PIC aboard a Citation II air ambulance, with another captain as my co-pilot. We carry a nurse, medic and enough equipment to handle any critical-care situation. Every flight requires weight and balance calculations based on actual weights, checking weather to not only confirm its flyable, but is comfortable for a patient on a life port and allows the medical crew to work on the patient in flight. Temperature considerations for power settings and takeoff/landing distances are critical, and a constant eye on changing weather conditions goes without saying. Although we train in our primary lessons on weight and balance, and how temperature and altitude play on the performance of our airplanes, we tend to rush through those calculations when we fly the same plane all the time.