British Airways (BA) Pilots are benefiting from a quieter Flight Simulator environment following the installation of ACH550 drives from ABB UK in an Air Handling Unit (AHU) at the their Flight Training Centre near London’s Heathrow Airport.

The AHU is used to cool the flight deck and instruments on one of their Boeing 777 Flight Simulators. Previously the AHU’s fan motor was run at constant speed but generated high noise levels. By using a 5.5 kW ABB ACH550 HVAC drive at 39 Hz, the same flow rate was achieved at a lower motor speed, resulting in a reduction in noise from 80 dB(A) to 73 dB(A). Reducing the unwanted background noise generated by the supply fan has made it easier for the crew to hear conversations and spoken instructions.

The critical nature of the Flight Simulators means that there are two AHUs: one in duty and the other in standby mode. Both AHUs are fitted with ABB 5.5 kW ACH550 HVAC drives. Supply ducts from each AHU feed air to the simulator. If the duty AHU fails or requires maintenance, a mechanical damper can be switched between the outlets of the AHUs to maintain airflow.
The switchover between AHUs is managed by a pressure signal to the building management system (BMS). This maintains a pressure of 860 Pa as the dampers are opened or closed by ramping the speed of the motors up or down as required.

In addition to the noise reduction, the drives cut energy costs, with a payback of less than a year. Dennis Doody, Senior Engineer with BA Flight Training says: “As well as this initial project, we have also used ABB drives on two other AHU installations, with significant savings in energy costs.”

A major requirement for a Flight Simulator is its fidelity to the environment that pilots experience in the actual aircraft. The noise from the AHU is not present in the real aircraft so BA had to find a way of removing the unwanted noise to make training easier and make the experience more realistic and relevant.
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