Air Management System (AMS) Flashcards
How is engine bleed air temperature regulated?
Engine bleed air temperature is regulated by a precooler and the Fan Air Valve (FAMV) which modulates fan air to cool the hot bleed air. (B12 14-02-10 Pg 4)
Which systems are provided with bleed air?
- Environmental Control System (ECS);
- Engine start;
- Engine anti-ice and wing anti-ice;
- Water pressurization.
(B12 14-02-10 Pg 1)
What unit has overall control of the system and how many channels does it have?
The AMS controller provides primary control for various airplane subsystems such as bleed control, air conditioning control, hot air leak
detection, crew oxygen monitoring and wing and engine ice protection. The AMS controller also interfaces with the smoke detectors providing fault detection, isolation, and reporting.
During the AMS operation, if the active channel fails, the control of the system will be automatically transferred to the other channel, with no interruption of AMS system functions. (B12 14-02-01 Pg 1)
What is the primary use of APU bleed air?
The APU is used primarily as a ground pneumatic source for the air conditioning packs (ECS) and engine starting. (B12 14-02-10 Pg 5)
How many overheat detection loops are there and how many zones are protected?
Normally the overheat sensors use dual loop sensing. In this configuration an overheat is indicated only when both loops detect an overheat condition. 6 Zones:
APU
Left Anti-Ice
Left Air Supply
Right Anti-Ice
Right Air Supply
Optional Trim System
(B12 14-02-10 Pg 7)
When a bleed air leak is detected, what indication is seen on the overhead pneumatic panel?
When leak is detected, the button amber striped bar is illuminated. (B12 14-02-05 Pg 1 & 2)
The Environmental Control System (ECS) provides conditioned air for which systems?
The Environmental Control System (ECS) provides pressurized and conditioned air for the flight deck and passenger cabin, filtered cabin air recirculation, conditioned air supply for gaspers, fan air cooling for avionics and emergency ram air ventilation for flight deck smoke clearance. (B12 14-02-15 Pg 1)
When will the emergency ram air ventilation valves operate?
Emergency ram air ventilation is provided in case of pack shutdown or for smoke removal. The flight deck pack emergency ram air ventilation valve is commanded OPEN only if both ECS cooling packs are commanded OFF or failed OFF and the plane’s altitude is less than
25000 ft.
The emergency ram air check valve will be open whenever the pressure in the ram air circuit is greater than cabin pressure.
(B12 14-02-15 Pg 4)
The gasper shut off valve is normally closed, when will it open and why?
During normal system operation the gasper shutoff valve remains closed. It automatically opens whenever the gasper air supply exceeds
35°C (95°F). This prevents hot air from blowing on the passengers during cabin heating. (B12 14-02-15 Pg 2)
When are the re-circulation fans commanded off?
The recirculation fans are commanded OFF when:
- Both packs are commanded OFF;
- During on ground, cabin warm-up mode with the APU as bleed source according to a function of ambient temperature and altitude;
- The cargo bay fire signal activates;
- The DUMP button is pressed;
- Smoke is detected in the recirculation bay.
(B1214-02-15 Pg 3)
What provides cooling air for the aft E-Bay?
Forced cooling is not necessary in the aft e-bay and, therefore, no fan is installed in this compartment. Air flowing from passenger cabin provides cooling of the aft e-bay and is expelled towards the underflow recirculation bay. (B1214-02-15 Pg 4)
In the optional forward cargo bay ventilation system, what happens in the event of smoke or fire being detected?
The ECS provides ventilation for live animals in the forward cargo bay. This optional system contains a fan on the side of the bay which provides underfloor recirculation air into the bay. The system contains a shutoff valve at the outlet of the bay that closes in the event of fire and thus preventing halon from leaving the bay. In addition, in the event of fire, the forward cargo compartment fan is commanded OFF, thus closing the check valve and preventing halon from entering the cabin. (B1214-02-15 Pg 4)
Which system supplies air for the gasper system?
Air flowing from the mixing manifold through the gasper check valve supplies the gasper ventilation system. When the gasper valve is opened, air from the right recirculation fan supplies the gasper system. (B12 14-02-15 Pg 2)
When will the positive pressure relief valve operate?
The positive pressure relief valve is a spring loaded check valve that works without any electrical power, and is independent the CPCS. Its function is to protect the airplane’s structure against damage due to positive overpressure. In case of outflow valve failure, the positive pressure relief valve opens if the pressure differential between cabin and surrounding environment exceeds 8.6 psi. (B12 14-02-20 Pg 2)
In manual mode, what must you be aware of?
In manual mode there is no automatic cabin depressurization on the ground (after landing).
The Dump Function is not available in Manual Mode. However, if the associated push button is pushed in, both recirculation fan and packs are turned to off. (B12 14-02-20 Pg 6)
If the dump function is selected, what happens in the system?
Provides rapid cabin depressurization, by opening the outflow valve (maintains rate of climb of 2000ft/min until cabin reaches 12400ft, then closes so cabin altitude climbs by natural leak) and commanding the packs and recirculation fans to off. (B12 14-02-05 Pg 5)
Where can the position of the outflow valve be seen?
On the ECS Synoptic Page of the MFD (B12 14-02-05 Pg 8 & 10)
In cruise mode, what is the maximum differential pressure and cabin altitude?
Above 37,000ft cabin altitude climbs up to 8,000ft and the maximum differential pressure is 8.4psi.
Up to 37,000ft (FMS cruise altitude or airplane actual altitude) cabin altitude climbs up to 8,000ft and the maximum differential pressure is 7.8psi. (B12 14-02-20 Pg 9)
During abort mode, what happens to the cabin
pressurisation?
The cabin altitude is scheduled back to the take-off altitude. (B12 14- 02-20 Pg 11)
When engine and APU bleeds are available simultaneously, the APU has priority when?
While the airplane is on ground and the APU is on, the AMS gives priority to APU bleed supply when all of the following conditions are met:
- The APU bleed and the cross-bleed push buttons are set to AUTO.
- The APU bleed valve and the cross-bleed valve are operating normally.
- Ground speed is below 50kt and 30s have passed after touchdown.
- Either REF ECS is OFF and REF A/I is not ALL on the MCDU T /0 DAT A SET MENU page or the airplane is single engine taxiing.
If groundspeed >50kts
- If only left engine - that engine supplies all bleed pressure.
- If only right engine - APU and engine supply bleed for packs 1 and 2 respectively.
(B1214-02-10 Pg 8)
With more than one bleed source available, what priority does the AMS use?
See table at B12 14-02-10 Pg 10 &11.
The exact priority depends on:
- Phase of Flight
- ENG REF ECS setting (ON / OFF)
- ENG REF A/1 setting
- APU Bleed Availability
(B12 14-02-10 Pg 9)
What are the main functions of the Air Management System (AMS)?
The AMS provides control over:
* Pneumatic system
* Environmental control system (ECS)
* Cabin pressure control system (CPCS)
What components does the AMS control?
The AMS controls:
* Environmental control
* Hot air leak detection
* Crew oxygen monitoring
* Wing and ice protection
* Smoke detection in the recirculation bay
* Fault detection, isolation, and reporting
What are the sources for the pneumatic system?
Pneumatic sources are:
* Engine bleed air
* APU bleed air
* External pneumatic source
What does the pneumatic system distribute air for?
It distributes air for:
* Engine starting
* Anti-ice systems
* Environmental control system (ECS)
* Water pressurization
How is bleed air regulated from the engines?
Bleed air is regulated by:
* Low-pressure check valves prevent reverse flow
* High-stage bleed valves regulate bleed air at low power
* Engine bleed valves regulate pressure at high power
* Temperature is controlled by pre-coolers using ram air or a fan
What is the role of the APU in the air management system?
The APU:
* Provides bleed air for ECS and engine start on the ground
* Supplies bleed air in flight when needed
* Prevents engine bleed air backflow using a check valve
