A320 Memory Items

Complete understanding of the Airbus A320 Memory Items. For training purposes only! Do not use it for flight.

Emergency Descent

EMERGENCY DESCENT

 

PRESSURIZATION NOTES

The cabin pressurization system has four general functions:

  • Ground function

Fully opens the outflow valve on ground

  • Prepressurization

During takeoff, increases cabin pressure to avoid a surge in cabin pressure during rotation

  • Pressurization in flight

Adjusts cabin altitude, and rate of change to provide passengers with a comfortable flight

  • Depressurization

After touchdown, gradually releases residual cabin overpressure before the ground function fully opens the outflow valve.

 

The system consists of:

  • Two Cabin Pressure Controllers (CPC)
  • One Residual Pressure Control Unit (RPCU )
  • One outflow valve, with an actuator that incorporates three motors (two for automatic operation, one for manual operation)
  • One control panel
  • Two safety valves.

In case of ditching, an override switch on the control panel allows the flight crew to close the outflow valve and all valves below the flotation line.

 

 

MODES OF OPERATION

  • Automatic: System receives data from FMGS and follows external schedules.
  • Manual: Crew uses the manual motor and sets landing elevation manually.

In normal mode, one CPC is active and one is on standby. Each CPC has a backup section which has its own power supply and a pressure sensor which generates cabin pressure and altitude signals to the ECAM.

GENERAL NOTES

• Two safety valves prevent the cabin pressure from going too high (>8.6psi) or too low (1psi below ambient).

• Automatic pressure control mode:

Two identical, independent controllers. One controller operates at one time. The automatic transfer occurs 70sec after each landing of if a controller fails.

The controller automatically controls the cabin rate. It limits the cabin altitude to 8,000’.

It uses the landing elevation from the FMGC and pressure altitude from the ADIRS. If FMGC is not available, the controller uses the baro reference from the Captain’s ADIRS and landing elevation from the panel.

• Mode Selector pb: If switched OFF for at least 10sec, it switches the controller when turned back to AUTO.

• Outflow valve position on ECAM page turns amber when a valve opens more than 95% in flight.

 

 

OXYGEN NOTES

The oxygen system consists of:

  • A cockpit-fixed oxygen system, which supplies adequate breathing oxygen to the cockpit occupants in case of depressurization, or emission of smoke and noxious gases.
  • A cabin-fixed oxygen system, which supplies oxygen for cabin occupants (passengers and cabin crew) in case of depressurization.
  • A portable oxygen system, which is provided in both the cockpit and cabin and is to be used:
  1. As PROTECTION for the crew during onboard emergencies.
  2. FIRST AID purposes.

 

 

THE COCKPIT’S FIXED OXYGEN SYSTEM CONSISTS OF :

  • A high-pressure cylinder, located in the left-hand lower fuselage.
  • A pressure regulator, connected directly to the cylinder that delivers oxygen, at a pressure suitable for users.
  • Two overpressure safety systems to vent oxygen overboard, through a safety port, if the pressure becomes too high.
  • A supply solenoid valve that allows the crew to shut off the distribution system.
  • Three (or four) full-face quick-donning masks, stowed in readily-accessible boxes adjacent to the crewmembers’ seats (one at each seat).

 

 

THE CABIN-FIXED OXYGEN SYSTEM

In the case of depressurization, the fixed oxygen system in the cabin supplies oxygen to the cabin occupants.

Chemical generators produce the oxygen. Each generator feeds a group of 2, 3, or 4 masks. Oxygen masks are located in containers above the passenger seats, in the lavatories, in each galley, and at each cabin crew station.

OPERATION

Each container has an electrical latching mechanism that opens automatically to allow the masks to drop, if the cabin pressure altitude exceeds 14 000 ft (+250, -750 ft), or 16 000 ft (+250, -750 ft) for the operation on high altitude airfields.

Members of the flight crew can override the automatic control.

When the masks are released, the passenger address system automatically broadcasts prerecorded instructions.

The generation of oxygen begins when the passenger pulls the mask towards the passenger seat. The chemical reaction used for oxygen generation creates heat. Therefore, the smell of burning, smokes and cabin temperature increase may be associated with the normal operation of the oxygen generators. The mask receives pure oxygen under positive pressure for about 13 min, 15 min, or up to 22 min, until the generator is exhausted.

A reset is available for the rearming of the system after the masks are restowed. A manual release tool allows crew members to open the doors manually in case of electrical failure.

 

 

EMERGENCY DESCENT MEMORY ITEMS

 

  • PF Announces……………………………….. “Emergency Descent”
  • CREW OXY MASKS………………………………………………….. USE
  • SIGNS……………………………………………………………………… ON
  • EMER DESCENT…………………………………………………INITIATE

If A/THR not active:

  • THR LEVERS………………………………………………………… IDLE
  • SPD BRK………………………………………………………………..FULL

When descent established:

SPEED……………………………………………. MAX/APPROPRIATE

If structural damage suspected:

MANEUVER WITH CARE

CONSIDER L/G EXTENSION

ENG MODE SEL…………………………………………………..IGN

ATC……………………………………………………………….. NOTIFY

Notify ATC of the nature of the emergency and state intention. The flight crew can communicate with the ATC using voice, or CPDLC when the voice contact cannot be established or has poor quality.

EMER DESCENT (PA)…………………………………….ANNOUNCE

The flight crew must inform the cabin of emergency descent on the PA system.

ATC XPDR 7700…………………………………………….CONSIDER

Squawk 7700 unless otherwise specified by ATC.

CREW OXY MASKS DILUTION……………………………NORM

‐ To save oxygen, set the oxygen diluter selector to the N position

‐ If the oxygen diluter selector remains set to 100 %, oxygen quantity may be insufficient to cover the entire emergency descent profile

‐ Ensure that crew communication is established with oxygen masks. Avoid the continuous use of the interphone to minimize interference with the breathing noise in the oxygen mask.

MAX FL: 100/MEA-MORA

If CAB ALT above 14 000 ft:

OXYGEN PAX MASK MAN ON……………………………..PRESS

This action confirms that the passenger oxygen masks are released.

Note: Notify the cabin crew, when the aircraft reaches a safe flight level, and when cabin oxygen is no more necessary.

 

 

 

EMERGENCY DESCENT  NOTES

 

The emergency descent should only be initiated on positive confirmation that cabin altitude and rate of climb are excessive and uncontrollable. However, the flight crew must rely on the CAB PR EXCESS CAB ALT warning, even if not confirmed on the CAB PRESS SD page. The CAB PR EXCESS CAB ALT warning can be triggered by a cabin pressure sensor, different from the one used to control the pressure and display the cabin altitude on the SD.

The flight crew should perform the actions of the EMER DESCENT in two steps:

‐ First step: Apply the memory items.

‐ Second step: Perform the read-&-do procedure (ECAM or QRH).

During the first step, the PM should focus on monitoring the FMA to ensure that the PF had correctly established the aircraft in descent.

During the second step, the PF should refine the settings.

To initiate the emergency descent, the use of autopilot (AP) and autothrust is highly recommended. At high flight levels, the flight crew should extend the speed brakes while monitoring the VLS . This is in order to avoid the activation of the angle of attack protection which may result in the retraction of the speed brakes and in AP disconnection.

Note: When in IDLE thrust, high speed and with speed brake extended, the rate of descent is approximately 7 000 ft/min. To descend from FL 390 to FL 100, it takes approximately 4 min and 40 NM.

The flight crew should be aware that the MORA displayed on ND is the highest MORA value within a radius of 40 NM around the aircraft.

The flight crew should suspect structural damage in case of a loud bang, or high cabin vertical speed. If the flight crew suspects structural damage, apply both of the following:

  • Set the SPEED/MACH pb to SPEED, to prevent an increase in the IAS, or to reduce the speed.

This action minimizes the stress on aircraft structure

  • Carefully use the speed brakes, to avoid additional stress on aircraft structure.

If the cabin altitude goes above 14 000 ft, the flight crew must press the MASK MAN ON pb. When it is obvious that the cabin altitude will exceed 14 000 ft, the flight crew could press the MASK MAN ON pb, before the cabin altitude reaches 14 000 ft.

Finally, subsequent to an emergency descent, once the oxygen masks are removed, the flight crew should perform all of the following:

  • Close the oxygen stowage mask compartment.
  • Press the PRESS TO RESET oxygen control slide, to deactivate the mask microphone, and to cut off the oxygen.

 

Below FL 100, the flight crew should limit the rate of descent to approximately 1 000 ft/min, except during the approach phase.

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