Air Flashcards
Learn the Air System
Why would the Compartment Temperature Inoperative (INOP) Lights Illuminate
- fault in the zone temperature controller
- Compartment Temperature Control is OFF
- the trim air switch is OFF
Describe the AUTO position of the Compartment Temperature Controls
- automatic compartment temp control
- pack output temperature is determined
by the cabin temperature controller.
What does the OFF position do concerning the Compartment Temperature Control?
- closes the compartment trim air valve
* the compartment temperature INOP light illuminates
TRIM AIR Switch ON/OFF
What occurs in each position?
ON – the trim air valve is commanded
open.
Off – the trim air valve is commanded
closed.
Trim Air OFF Light Illuminated (amber) Why?
The TRIM AIR switch is off.
PACK RESET Switches. Why use them?
Resets an overheated pack if the pack has cooled to a temperature below the overheat level.
Pack INOP Lights. Why illuminated?
- the pack is overheated
* fault in the automatic control system
Pack Off Light?
PACK VALVE Closed
PACK Control Selectors
OFF or AUTO Describe each position.
OFF—-closes the pack valve.
AUTO– the pack is automatically controlled.
PACK Control Selectors
STBY MODE
- N (normal) – constant, moderate temp
- C (cool) – full cold operation
- W (warm) – full warm operation
FOOT HEATERS Switch
- HIGH – operates on high setting(inflight)
- LOW – operates on low setting.
- OFF – is not operating
Which FOOT HEATER position will only work inflight only?
The High Position
Which SHOULDER HEATER position will only work inflight?
The High Position
What will cause the Equipment Cooling SMOKE Light to illuminate?
Smoke is detected in the forward equipment cooling ducts.
Describe the Alternate (ALTN) Equipment Cooling Switch
- activates the alternate supply fan
- On the 757-200ER activates the
auxiliary fan, if the alternate supply fan fails.
The Equipment Cooling Overheat (OVHT) Light illuminates for 3 reasons.
- insufficient airflow (on the ground)
- the supply fan is inoperative
- the alternate supply fan is inoperative
When you rotate the Cabin Altitude AUTO RATE Control
You are setting a limit for cabin altitude rate of climb or descent during auto control.
What is the function of the DETENT position?
Establish an approximately 500 fpm climb and 300 fpm descent
What has happened when you see AUTO Inoperative (INOP) Light
Either:
AUTO 1 and AUTO 2 cabin altitude control functions are inoperative or,
MAN mode is selected
Cabin Altitude MODE SELECTOR
Auto 1
Auto 1 –
• activates Auto 1 cabin altitude control for
automatic operation
• outflow valve positioned automatically
Cabin Altitude MODE SELECTOR
AUTO 2
Auto 2 –
• activates Auto 2 cabin altitude control for
automatic operation
• outflow valve positioned automatically
When you select MANUAL on the Cabin Altitude MODE SELECTOR, what happens?
• outflow valve position is controlled by the
cabin altitude MANUAL control
• AUTO INOP light illuminates
What is the takeoff and landing Cabin differential pressure limit/placard?
.125 PSI
The CABIN ALTITUDE light illuminates for what reason?
• cabin altitude exceeds 10,000 feet
• extinguishes when cabin altitude
descends below 8,500 feet.
What is the function of the High Altitude Landing Switch?
Reprograms system logic to initiate AUAL and VISUAL alerts at 14,650’ instead of 10,000’
why would the High Altitude Landing Inoperative light illuminate?
The High Altitude Landing System is failed.
what is the purpose of the Bleed Air System Isolation Switch?
To open or close the ISOLATION VALVE.
If you notice the ISOLATION VALVE light, what is occurring?
The isolation valve position disagrees with the commanded position.
The engine BLEED AIR switches open when?
They open when engine bleed air is available. Pneumatic actuated.
What are the 3 reasons the Engine Bleed Air OFF light illuminate?
The engine bleed air valve is closed:
• automatically due to a system fault
• the switch is OFF
• the engine is not running
Why would a DUCT LEAK Light occur?
A high temperature bleed air leak is detected.
Why would a BLEED Light occur?
The engine bleed air temperature is excessive.
Why would a HI STAGE Light occur?
Engine bleed system pressure is excessive or
the engine high pressure bleed air valve
is automatically locked closed.
What would cause a APU Bleed Air VALVE Light to Illuminate (amber)
APU bleed air valve position disagrees with commanded position.
How many temperature zones in the 757
Three, Flight Deck and two Cabin zones.
How is zone temperature satisfied?
Zone temperature is then satisfied
by the zone temperature controllers using trim air.
What occurs when there is an internal pack overheat?
The pack valve closes and the pack is shut down automatically.
During an internal pack overheat what lights will you see?
The PACK OFF light illuminates.
EICAS advisory L or R PACK OFF
PACK TEMP indications.
What happens when you shut off the LEFT RECIRC FAN?
The overboard exhaust valve will open. Maintenance action is then required
Why turn off the RIGHT RECIRC FAN?
To provide a more rapis exchange of air.
Where does the Flight Deck get its air?
From the LEFT PACK only.
Where does the Flight Deck get its air if the LEFT PACK has failed?
The flight deck receives air from the mix manifold.
How much does our Fuel Flow increase with a fan off?
.3%
How does the FORWARD E/E system get cool?
The left recirculation fan draws air through the forward E/E system and returns it
to the mix manifold.
What happens if the TRIM AIR system is off?
The packs attempt to maintain all
compartments at an average temperature.
How does the forward equipment cooling system work?
The system has a supply fan that
draws cooling air from the cabin and forces it through the equipment racks and
avionics.
After the forward equipment is cooled, where does the air go?
The air is then exhausted into the air conditioning mix manifold by the
left recirculation fan.
What occurs while the forward equipment is cooled and there is a low differential pressure?
The overboard exhaust valve automatically opens and most of the air is exhausted overboard.
What lights will you view if a supply fan fails?
Equipment cooling OVHT light illuminates
EICAS advisory EQPT OVHT displays
What should be done after the supply fan fails?
Pushing the ALTN EQUIP COOLING switch,
an alternate supply fan is activated
What happened if the OVHT light illuminates after the ALTN Fan was in operation?
The alternate supply fan failed.
(The OVHT light re-illuminates)
(EQPT OVHT message re-displays)
The 757-200ER has what backup for cooling of the ESSENTIAL avionics and electrical equipment
If both supply fans are inoperative
an auxiliary fan automatically operates to provide cooling for essential avionics
and electrical equipment.
In the 757-200ER what is the backup power source?
The hydraulic driven generator.
The 757-200ER has what feature on the ground concerning inadequate cooling airflow?
On the ground, the OVHT light illuminates, the EQPT OVHT message displays
and the ground crew call horn sounds if insufficient cooling airflow is detected.
What happens when smoke is detected in the equipment cooling system?
SMOKE light illuminates.
EICAS advisory FWD EQPT SMOKE displays when smoke is detected in the equipment cooling system.
What happens automatically when smoke is detected in the equipment cooling system?
- one or both recirculation fans turn off
- one or both AC packs switch to high flow
- the overboard exhaust valve opens
How would you describe the cargo heat system?
Completely automatic.
What protects the fuselage from excessive pressure differential?
Positive pressure relief valves and negative pressure relief valves operate
independently from the pressurization control system to protect the fuselage
against excessive pressure differential.
Whwn will the CABIN ALT and CABIN ALTITUDE lights illuminate while the HIGH ALTITUDE LDG switch is on?
If the cabin altitude climbs above 14,650 feet . The lights extinguish and the EICAS message blanks when the cabin altitude descends below 11,800 feet.
Describe the aneroid switch.
Automatically closes the outflow valve when the cabin altitude exceeds 11,000 feet. Some models are auto and manual mode. Some models are auto only.
APU air is available up to __________feet.
17,000 feet
When would the BLEED ISOLATION be open?
Engine start
Single bleed source operation
Whay would you see a L or R BLD DUCT LEAK?
A high temperature bleed air leak is detected
What is the cause of a BLEED light on a 757?
How many resets allowed?
BLEED LIGHTS:
- 757: “Bleed” = over temperature
(1 reset allowed)
What is the cause of a High Stage light on a 757?
How many rests?
“High Stage” = over pressure
No reset
