HEATING – LIMITATIONS
Refer to AW139-RFM-4D Supplement 2.
AIR CONDITIONING - GENERAL
The purpose of the air conditioning system is to supply cool air to the cockpit
and the cabin to maintain a comfortable environment.
The air conditioning system comprises two vapour cycle systems, one for the
cockpit and one for the cabin, which use tetrafluoroethane (Freon) as
refrigerant. Freon is non-toxic and non-flammable gas. Each system
includes a compressor, a condenser, a heat exchanger and an evaporator.
The compressors are mechanically driven by the Main Gear Box (MGB)
through electromagnetic clutches.
The clutches open – thus mechanically disconnecting the compressors from
the MGB – when the air conditioning is off.
Two Air Conditioning Control Boxes (ACCBs) compare the air temperature
measured by the cockpit and cabin sensors with the temperature set on the
ECS control panel and operate the related compressor on/off cycle as
necessary.
Freon cools the ventilation air through the heat exchangers located in the
cockpit and cabin ventilation ducts. In NORM mode the ventilation flapper
valves are open and ram air is cooled. In RECYCLE mode the ventilation
system flapper valves are closed and the recycle flapper valves are open:
cockpit and cabin air is recirculated through the heat exchangers by the
electrical fans and cooled.
The air conditioning system is supplied by circuit breakers grouped as ECS
and connected to NON-ESS 1 (cockpit) and NON-ESS 2 (cabin).