EMERGENCY RAM AIR INLET - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General
The emergency ram-air inlet gives a flow of fresh air through the aircraft if there is a failure in the two air conditioning packs. An actuator extends and retracts the emergency ram-air inlet. A Check valve prevents the flow of air in the opposite direction. A Low Pressure (LP) ground connection is installed for connection of a ground air supply.

** ON A/C NOT FOR ALL

2. Component Location

Emergency Ram-Air Inlet - Component Location ** ON A/C NOT FOR ALL

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
** ON A/C ALL
3HZ	RELAY-RAM AIR CLOSE CTL	103VU	126	21-55-00
4HZ	P/BSW-AIR COND/RAM RAM AIR	30VU	210	21-55-00
5HZ	RELAY-RAM AIR OPENING CTL	103VU	126	21-55-00
4022HM	EMERG RAM AIR CHECK VALVE	131PW	137	21-55-41
7HZ	EMERG RAM AIR ACTUATOR		137	21-55-51

** ON A/C NOT FOR ALL

3. System Description

Emergency Ram-Air Actuator and Check Valve Component Description Views

Air Conditioning Panel - Location View ** ON A/C NOT FOR ALL

Emergency Ram-Air Inlet - Electrical Schematic

If during a flight there is a failure in the two air conditioning packs 10HM (11HM), you can push the RAM AIR pushbutton switch 4HZ.
When you push the RAM AIR pushbutton switch:

the altitude of the aircraft must be less than 10000 ft. (3050 m),
the cabin differential pressure must be less than 70mbar (1.0 psi).

The emergency ram-air-inlet actuator 7HZ extends and the emergency ram-air inlet moves into the external airflow. Fresh air is pushed into the ram air system and flows through ducts to the mixer unit in the cabin air distribution and recirculation system.
The cabin pressure controllers 11HL (12HL) control the outflow valve 10HL to an approximately 50% open position.

You can connect a ground air cart to the LP ground connection for ventilation of the aircraft. It is not necessary to operate the air conditioning packs.

A. Emergency Ram-Air-Inlet Actuator
The emergency ram-air-inlet actuator 7HZ is installed on the emergency ram-air inlet in the LH belly fairing of the fuselage. It opens and closes the emergency ram-air inlet.

B. Check Valve
The check valve 4022HM is installed in the duct to the mixer unit. The emergency ram-air duct and the LP ground connection duct are connected upstream of the check valve. This makes sure that air from the mixer unit cannot flow out through the emergency ram-air inlet or the LP ground connection.

** ON A/C NOT FOR ALL

4. Component Description

A. Emergency Ram-Air Inlet Actuator FIN: 7-HZ

Emergency Ram-Air Actuator and Check Valve Component Description Views

The emergency ram-air inlet actuator 7HZ has:

an actuator body assembly (1),
a split-field 28 V DC series-motor which has an electromagnetic brake (2),
a two-step gear-train (3),
a jack screw (6),
an actuator ram (9),
two indication microswitches (7),
two travel limit switches (8),
a shop-adjustable clutch mechanism (5),
a filter circuit board for EMC reasons,
an electrical connector (4).

The electrical motor (2), attached to the actuator body (1), drives the gear-train (3). The gear-train drives the jack screw (6) into/out of the actuator ram (9). This changes rotary motion into linear motion to extend or retract the actuator ram (9). Two microswitches (7) signal the fully extended/retracted position of the actuator ram (9). Two limit switches (8) are located between the two microswitches. These remove electrical power from the motor when the actuator ram (9) is at its fully extended/retracted positions.
A clutch mechanism (5) disengages the jack screw (6) from the gear-train (3) if the emergency ram-air inlet becomes accidentally blocked. An electrical connector (4) connects 28 V DC from the aircraft electrical supply system to power the actuator.

B. Check Valve

Emergency Ram-Air Inlet - Component Location ** ON A/C NOT FOR ALL

Emergency Ram-Air Actuator and Check Valve Component Description Views

The check valve 4022HM is installed in line with the air delivery duct, between the emergency ram-air inlet and the mixer unit. It consists of a tubular housing with two semicircular flaps installed on a hinge bar. The flaps can open in one direction only and a spring holds them in the closed position. Air flow from the emergency ram-air inlet, (or the low-pressure ground connection) will cause the flaps to open. This allows the air to pass through the check valve to the mixer unit. Air flow in the opposite direction will cause the flaps to close onto their seats and stop the airflow.

** ON A/C NOT FOR ALL

5. Operation/Control and Indicating

Air Conditioning Panel - Location View ** ON A/C NOT FOR ALL

Emergency Ram-Air Inlet - Electrical Schematic

You must only operate the emergency ram-air inlet if:

there is a failure in the two air conditioning packs 10HM and 11HM,
the altitude of the aircraft is less than 10000 ft. (3050 m) (to prevent passenger discomfort),
the difference between the pressure in the fuselage and the external pressure is less than 70mbar (1.0 psi). If the difference in pressure is more, the check valve 4022HM cannot open, no emergency ram air flows in.

A. Opening of the Emergency Ram-Air Inlet
To open the emergency ram-air inlet you must lift the guard and push the RAM AIR pushbutton switch 4HZ. When you push it:

a signal is sent to the cabin pressure controllers 11HL (12HL) and the outflow valve 10HL partially opens,
a signal is sent to extend the emergency ram-air-inlet actuator 7HZ and the emergency ram-air inlet flap moves into the external airflow,
the ON legend in the RAM AIR pushbutton switch 4HZ comes on,
actuator position data is sent to the SDACs,
on the lower ECAM display unit, the BLEED page shows the RAM AIR symbol open.

B. Closing of the Emergency Ram-Air Inlet
To close the emergency ram-air inlet, you must lift the guard and push the RAM AIR pushbutton switch 4HZ. When you push it:

a signal is sent to the cabin pressure controllers 11HL (12HL) and the outflow valve 10HL closes as necessary,
a signal is sent to the emergency ram-air-inlet actuator 7HZ and the emergency ram-air inlet closes,
the ON legend in the RAM AIR pushbutton switch 4HZ goes off,
actuator position data is sent to the SDACs,
on the lower ECAM display unit, the BLEED page shows the RAM AIR symbol closed.

The emergency ram-air inlet closes automatically if you push the DITCHING pushbutton switch 13HL (Ref. AMM D/O 21-31-00-00).

C. LP Ground Connections
If you connect a ground air cart to the LP ground connection, the air flows into the mixer unit (Ref. AMM D/O 21-21-00-00). It is not necessary to operate the air conditioning packs to ventilate the aircraft.

[Rev.10 from 2021] 2026.04.02 06:48:23 UTC