Colgan Air Flight 3407 was a very interesting case to watch. On February 12, 2009, at 10:17 pm, Flight 3407 crashed into a house in New York after the pilots suffered a stall. Flight 3407 was scheduled to fly from Newark, New Jersey to Buffalo, New York. The NTSB reported that the cockpit voice recorder (CVR) revealed some discrepancies experienced by both pilots. The first officer had no experience with icing conditions, but icing was one of the reasons the plane stalled. On the other hand, the captain had some experience flying in icing conditions. The captain was tired, making him unable to recover from a stall. With this in mind, the Human Factors Analysis Classification System (HFACS) will provide information on some errors made by both pilots. According to "A Human Error Approach to Aviation Accident Analysis...", both authors stated that the HFACS was developed based on the Swiss Model Cheese project to provide a support tool in the investigation process to identify probable human cause (Wiegmann and Shappell, 2003). Furthermore, the HFACS is divided into four categories to identify the fault that occurs. In other words, before adverse events occur, the HFACS will identify the type of error that occurs. The first HFACS is an unsafe act. Unsafe acts start at the first level and are divided into two categories: errors and violations. While errors are based on skills, decisions and perceptual errors, violation focuses on routine and exceptional violations. Regarding Colgan Air Flight 3407, the unsafe act elements that both pilots acted upon were decision-making and skill-based errors. Skill-based errors occurred when the crew did not pay attention to speed and the captain also did not attempt to recover from a stall. For the decision error, the co-pilot had discovered icing on the wings but had not mentioned the severity of the error. The next level is Precondition for Unsafe Acts. The precondition starts at level two and is divided into environmental factors, operator conditions and personnel factors. Regarding Flight 3407, the environmental factors would be weather conditions. Icing was a major factor when occurring on the wings. Both pilots felt tired during the flight. They pushed their body to the limits where their reaction times were not fully functional. Furthermore, due to fatigue and inadequate situational awareness, the crew did not perform their job optimally.