During our flying training, we learn to calculate weight and balance for the aircraft we are going to fly. We learn about centre of gravity, basic empty weight, arms aft of the datum, moments and envelopes and how to graph the weight and balance for the beginning and end of flight. Like runway takeoff and landing distance calculations, weight and balance is one of the first aspects of flying that pilots tend to forget once they are flying in the real world. Part of the reason is that the calculations seem very complex.

The weight and balance calculation can, however, be greatly simplified, to the extent it an almost be done mentally and to an accuracy quite sufficient for safety.

Why is the weight and balance calculation so important ? Many pilots think it’s simply to do with getting the aircraft off the ground in the runway distance available. You hear it said that "the runways here at Cambridge and at our destination are more than long enough and you can never have too much fuel aboard". Wrong!! Each aircraft is allocated a maximum takeoff weight by the manufacturer, which should not be exceeded. In the case of Cessna 172s, this weight is 1091 kilograms. More than a question of getting the aircraft off the ground, it is a question of flying the aircraft within manufacturing tolerances and not placing stress on the airframe that it was not designed to withstand.

The "Correct Weight" software, which can be downloaded from the ACST Web site, simplifies the passenger, baggage and fuel calculation to a few keystrokes and works for the club’s most popular aircraft. It includes the latest acquisition, the Jabiru 160.

The program is installed on the members’ computer at the Club for your pre-flight convenience. Just fill in your passenger and baggage weights for each seat and the program will instantly tell you if you are under or over weight. If you are overweight, it will advise you of the maximum fuel you can carry for your flight.

Please note: the program requires that Microsoft .NET Framework 2.0 be installed on your system. It is available for download from the Microsoft web site and is found on most Computer Magazine cover CDs.