Although the pilots had totaled up the take-off weight of the aircraft before the flight and determined it to be within limits, the plane was actually overloaded and out of balance due to the use of incorrect Federal Aviation Administration (FAA)-approved passenger weight estimates. When checked, the National Transportation Safety Board found that the actual weight of an average passenger was more than 20 pounds (9 kg) greater than estimated. After checking the actual weight of baggage retrieved from the crash site and passengers (based on information from next-of-kin and the medical examiner), it was found that the aircraft was actually 580 pounds (264 kg) above its maximum allowable take-off weight with its center of gravity 5% to the rear of the allowable limit.