Weight and balance calculations are an important part of a pilot's preflight preparation. Failure to ensure that an airplane is loaded within limits can be deadly. The crash of a Piper Malibu Mirage on August 4, 2000 is a prime example of what can happen if takeoff is attempted in an overloaded airplane.
The morning of the accident, the fuel tanks were topped off, and the pilot, his two passengers, their luggage and their large dog then boarded the aircraft. The takeoff runway has an upslope of 1.2 degrees and is 3,900 feet long. The opposite down sloping runway was available at the time of the accident with nearly calm winds.
During the takeoff witnesses noted that it was about ten feet above the runway in a nose high attitude, but not climbing. The Mirage narrowly cleared a six-foot fence at the departure end of the runway. Shortly after clearing the fence, the airplane collided with a utility pole, the roof of a bus stop, and a brick wall 150 feet beyond the utility pole. The pilot and all passengers were killed. Weather was not a factor in the accident.
The airplane was loaded with cargo weighing 268 pounds. The pilot and passengers were a combined weight of 627 pounds, and the fuel tanks contained 120 gallons (720 pounds) of 100 LL fuel. The basic empty weight of the Mirage was 3097 pounds. According to Piper, the maximum takeoff weight is 4318 pounds. The airplane was 394 pounds over gross at takeoff.
The commercial pilot had over 6,000 hours of total flight time, and 80 hours in the Mirage.
According to the NTSB, the cause of this accident was the improper preflight planning by the pilot, which resulted in taking off with the airplane exceeding the weight and balance limitations. A factor in the accident was the pilot taking off from a short, up sloping runway.
According to ASI's Ups and Downs of Takeoffs and Landings Safety Advisor, 50% of all accidents occur during takeoff or landing. Takeoff on an up sloping runway will result in a longer takeoff distance. Also, acceleration of the aircraft will be slower. An overweight takeoff will also result in reduced climb performance. Also, watch ASI's Takeoffs and Landings safety video series.
For more information, you can also read Bruce Landsberg's article, "Loaded" from the September 2002 issue of AOPA Pilotmagazine.
This accident report as well as others can be found in ASI's Online Database.