MIL-STD-704: Aircraft Electric Power Characteristics
MIL-STD-704 defines the requirements outlined by the Department of Defense for the characteristics of aircraft electric power generated at the input terminals of electric utilization equipment. MIL-STD-704 is intended to detail electric power quality requirements for DoD aircraft, but may also be used with commercial planes or other vehicle types. Standards like ISO 1540 and SAE-AS1212 also dictate aircraft electric power requirements, but are not generally relevant for military aircraft, as they do not address the areas of concern for military aircraft electric power quality and need wider limits compared to MIL-STD-704. MIL-STD-704 also takes into account legacy DoD equipment and aircraft electrical systems.
General Requirements
4.1 Aircraft Electric Power System Requirements
Aircraft electrical power systems should offer electric power with the characteristics specified in this standard at the utilization equipment terminals during all powerations of the power system.
Airframe manufacturers or modifiers are responsible for offering the distribution and protection network to the terminals of the utilization equipment while maintaining power characteristics specified in MIL-STD-704; characteristics of the power measured at the output terminal of an unregulated power source or the POR of a regulated power source should be within the limits specified in the detail specification applicable to the power source.
Protective devices should operate independently of control/regulation equipment.
4.2 Aircraft Utilization Equipment Requirements
Utilization equipment should be compatible with the power characteristics specified in MIL-STD-704.
Aircraft should operate at the performance level specified in its detail specification in all of the following modes of operation:
Normal
Abnormal
Transfer
Emergency
Starting
Loss of power or the loss of one or more phases of AC should not result in