How are calculations performed?

Power Check works in the same manner as plotting the charts manually. The program uses the flight manual chart and procedure.

Each graph was enlarged so that it may be measured down to less than a single degree of turbine temperature, or to within 0.1% of torque, even less for Ng values. The intersection of each element of the chart was measured in a 3D fashion, and then this data is placed in a database table. When you enter your test data, the table is read into memory, and a precise result can be calculated.

Many of the flight manual procedures require you to alter the input data slightly for things such as sand filters or particle separators. Some helicopters manuals specify torque adjustments depending on air speed, or adding / subtracting the OAT reading for different engine models fitted. Power Check makes all these adjustments for you.

The data from your helicopter's test is checked for errors, flight manual limitations and validity, both before and after plotting on charts.

How accurate are the results?

The result is calculated to within 1°C turbine temperature, 0.1% of engine torque, and 0.05% Ng speed. However, the instruments fitted to the helicopter often don't provide that kind of accuracy, and it's not possible to fly your helicopter to within such tiny margins of torque. So the end result depends greatly of how well the aircrew performs the test, and records the instrument values.

One of the best features is that Power Check doesn't make any human errors. Humans make errors like forgetting the quirks of each chart procedure, and worst of all using the blunt end of one's index finger as a chart plotting tool.