An industry-wide survey indicates the need for power take-off pads on gas turbine engines intended for helicopter power plant installation. Specific attention has been given to this problem as related to the free turbine type of gas turbine engine. The gas generator of free turbine engines may be operated while the power turbine engine section is locked (O RPM). Under these conditions it may be desired to operate the gas generator in order to provide auxiliary power to the aircraft for various purposes. The purpose of this document is to summarize these requirements.