Concorde Air Conditioning & Ventilation Distribution
The main air extraction system supplies cooling air to the equipment racks in the flight compartment, rear fuselage and beneath the floor.
The system is controlled from panel 2-214 at the Flight Engineer’s station and must be operating when the electrical systems are energized. The forward extraction system is energized automatically through a landing gear weight relay.
The air supply normally exceeds that extracted to ensure a small positive pressure which prevents inward leakage from the under-floor space to the racks. On the ground, pre-conditioned air is normally supplied from a ground air conditioning unit, but in its absence sufficient circulation can be obtained through open cabin doors.
Fresh air distribution and the ventilation of the hydraulic, battery and fuel compartments are arranged as separate sub-systems.
Forward Supply Fans
There are two axial flow fans, one on each side of the under-floor bay in the area identified as zone 123/4, extract air from the passenger compartment and supply it to the forward equipment racks.
Forward Extraction Fans
There are also three axial flow fans at a junction of the extraction ducting in zone 125/6. These extract air from the flight compartment and forward equipment racks, and discharge it overboard through the forward regulating and safety valves. When weight is on the landing gear and the busbars are energized, these fans run automatically.
Rear Extractions Fans
The system has three mixed flow fans beneath the floor in the area identified as zone 153/4. These extract air from the rear equipment racks and discharge it into the under-floor space.
Controls and Indicators
Controls and indicators are grouped together on the EQUIPMENT BAY COOLING section of panel 2-214 at the Flight Engineer’s station. There are amber FLOW warning lights that indicate any air flow failure in the forward and rear extraction ducts, and the master warning system gives an AIR warning. The rear extraction standby fan has no separate indicator; however the FLOW warning light indicates its operation. The air flow failure system serves as the inertial navigation system ventilation failure warning, and the ground call horn sounds if there is no air flow.
Precise air flow in the forward extraction duct is shown on a MASS FLOW indicator, which reads from O to 1 kg/sec.
A red segment indicates air flow below the acceptable minimum. Separate indication of forward emergency relief valve operation is given by a magnetic indicator which shows OPEN or SHUT.
A magnetic indicator for the HYD BAY FAN is also on this panel. The caption lights incorporate diodes to prevent feed-back when a filament test is carried out. They also incorporate a dimming facility. Pressing the cap of the FLOW warning lights checks the serviceability of the associated AIR master warning channel.
Fresh Air Distribution
Air from the ground conditioned air supply is directed to the flight compartment and the forward and rear passenger compartments and is removed by extraction through the Flight Engineer’s panel, circuit breaker panels, electronic racks, passenger compartment windows, toilets and galleys. The operation of the system follows automatically from the flows created by the air extraction systems and no supervision is required apart from the adjustment of crew and passenger louvers. The forward baggage compartment is cooled, or heated, by air ducted from the flight compartment air supply ducts, through flexible ducts at every frame bay along its length. This air circulates around the outside of the baggage compartment.
The rear baggage compartment is ventilated by fresh air from a roof duct. This is done by means of a changeover valve in the forward end of the duct; the air supply may be diverted via the wall ducting to the under-floor bay from where it is finally discharged overboard.
Forward Equipment (Hydraulic Chassis) Ventilation
The forward hydraulic chassis is shrouded and ventilated to contain any hazard from hydraulic oil mist. Ventilating air, which is induced by cabin differential pressure, flows from the flight compartment via the rudder pedestals and the centre console to the hydraulic chassis bay. The air is then discharged overboard through a vent nozzle in the skin of the forward equipment bay via an electrically actuated butterfly vent valve. The control and indication for the valve are on the Cabin Pressure Control panel at the Flight Engineers station, and a pressure switch provides a barometric override control of the system.
28 VDC from the main busbars supplies the ventilation valve actuator and the magnetic indicator via the pressure switch
Battery Venting System
The aircraft batteries are vented to atmosphere through two inter-connected pipes. Both these pipes incorporate relief valves and drain valves, and terminate in overboard vents immediately forward of the nose gear bay.
When fitted, the flight test instrumentation batteries are vented in a similar manner to the main batteries. The system is connected to the main battery venting system near the left hand overboard vent.
The drain valves are attached to the drain outlets of the relief valves, and allow the fumes and excess pressure released by the relief valve to escape into the underfloor area. Steel receptacles retain any fluid released by the relief valves. The system operates automatically and no supervision is required except to ensure that the drain receptacles do not go un-emptied.
Vapour Seal/Fuel Tank Interspace – Ventilation System
There are three fuel tank systems within the fuselage that are sealed, ventilated and drained to eliminate hazard from fuel leakage. Viton coated fabric membranes extend over the tops and end of tanks 6, 8, 9 and 10 and over the forward bulkhead of tank 11.
Passenger compartment discharged air is ducted from the under-floor space and the rear galley area, flows through the systems and then discharges overboard. Cabin differential pressure causes the air to flow, and there are no manual or automatic controls of the system.
Fuel leaking into the vapour seal air space is passed overboard either by gravity feed through the drain pipes, or siphoned off by the air bleeds into the vent pipes from the low points of the catenary floor, and the lower part of tank 11 vapour seal.
Rear Equipment Compartment Purging System
The rear equipment compartment is purged of fuel and hydraulic fluid vapour by air, discharged from the passenger compartment. Air from the compartment is discharged overboard through two ventilation outlets.