Identify the two primary sources of electrical power for the UH-60 and how power is distributed across buses.

Identify the two primary sources of electrical power for the UH-60 and how power is distributed across buses.

• A. External power is the only source; there is no engine-driven generation.
• B. Two battery banks supply all buses directly.
• C. Power is distributed to the main bus only, with no essential/nonessential differentiation.
• D. Two Integrated Drive Generators on the engines provide electrical power, with external power available if connected; power is distributed to essential, nonessential, and main buses via the electrical system and switchgear.

Answer: (D)

Two engine-driven Integrated Drive Generators are the primary electrical power sources, with external power available when connected. From there, power is sent to three buses through the aircraft’s electrical system and switchgear: the essential bus, the main bus, and the nonessential bus. The essential bus powers critical flight instruments and controls and other systems needed to maintain safe flight. The main bus supplies the majority of loads for the helicopter’s systems, while the nonessential bus handles equipment that isn’t required for immediate flight safety. The switchgear and bus-tie arrangements allow power to be shared between sources and between buses, so if one source or bus drops, others can take over while preserving essential systems. External power can substitute or augment engine-driven generation when connected, ensuring the system remains powered even with engines not running.

Two engine-driven Integrated Drive Generators are the primary electrical power sources, with external power available when connected. From there, power is sent to three buses through the aircraft’s electrical system and switchgear: the essential bus, the main bus, and the nonessential bus. The essential bus powers critical flight instruments and controls and other systems needed to maintain safe flight. The main bus supplies the majority of loads for the helicopter’s systems, while the nonessential bus handles equipment that isn’t required for immediate flight safety. The switchgear and bus-tie arrangements allow power to be shared between sources and between buses, so if one source or bus drops, others can take over while preserving essential systems. External power can substitute or augment engine-driven generation when connected, ensuring the system remains powered even with engines not running.