Recall bad passenger weight estimation being a contributory factor in the following crash.
Air Midwest Flight 5481 - Wikipedia, the free encyclopedia
"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, but
Federal Aviation Administration (FAA)-approved, passenger weight estimates. When checked, the
National Transportation Safety Board found that the estimates were over 20 pounds (9 kg) lighter than the actual weight of an average passenger. 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."
"As a result of the weight issues discovered, the FAA planned to investigate and potentially revise estimated weight values, something that had not been done since 1936.
Air Midwest used an average weight of 200 pounds (90.7 kg) per passenger after the accident, but the NTSB suggests that airlines use actual weights instead of average. 70% of small air carriers still use average"