What is the function of a bus tie in avionics power distribution?

What is the function of a bus tie in avionics power distribution?

• A. It connects two buses to allow allocation of power between them and maintain essential power if one bus drops
• B. It measures voltage on the bus
• C. It isolates all buses in fault
• D. It disconnects the avionics from power

Answer: (A)

The bus tie creates a cross-connection between two power buses, allowing power to be shared or transferred from one bus to the other. This lets you allocate power between buses and keep essential avionics powered if one bus drops. In normal operation, each bus feeds its own loads, but when a fault or generator issue occurs on one side, closing the bus tie lets the healthy bus back-feed the affected side, preserving critical systems with safe transfer sequencing. The bus tie is typically a controlled switch or relay that is opened or closed by the power-management system or crew, with interlocks to prevent unsafe backfeeding. It isn’t used for measuring voltage, isolating every bus in a fault, or disconnecting avionics from power by itself.

The bus tie creates a cross-connection between two power buses, allowing power to be shared or transferred from one bus to the other. This lets you allocate power between buses and keep essential avionics powered if one bus drops. In normal operation, each bus feeds its own loads, but when a fault or generator issue occurs on one side, closing the bus tie lets the healthy bus back-feed the affected side, preserving critical systems with safe transfer sequencing. The bus tie is typically a controlled switch or relay that is opened or closed by the power-management system or crew, with interlocks to prevent unsafe backfeeding. It isn’t used for measuring voltage, isolating every bus in a fault, or disconnecting avionics from power by itself.