M11.12 Flashcards
What is the heating element in an electrical heating circuit usually made up of?
A metal wire, power supply and a temperature or power control unit
How many different types of temperature control are used in aircraft electrical heating circuits?
Two: a bimetallic switch or an electronic switch
With window heat operation, what is the maximum demand of heating power?
2 kW
What type of coating provides up to a 100° contact angle?
Hydrophobic coating
Why don’t we operate the optical ice detector systems all of the time?
Because it takes hot air from the engines which reduces their performance and economy
What does the rotary type ice detector consist of?
Consists of a single phase AC motor that drives a serrated rotor in close proximity to a stationary knife edge cutter
What are the main components of a window heat system?
The window itself, the temperature control and the monitoring circuit
What type of fluid is used for chemically deicing a propeller?
Glycol-based fluid
What are deicer boots made out of?
A soft, pliable rubber, or rubberised fabric
What are the five procedures you should carry out to make sure the deicer boot has maximum life?
Do not drag refuelling hoses over the deicing boot, keep the surface of the boots free from fuel, grease and dirt, do not lay tools on or lean maintenance equipment against the boots
When is the manual override function is on thermal anti-ice valves?
When there is a valve or system failure
When does the solenoid control valve close by spring force?
When there is no air pressure
The part of the ice detector you can see outside the aircraft is called what?
Magnetostrictive probe tip
In the engine anti ice system, where are the two places the air can come from?
Engine bleed air and the pneumatic system
What are the two negative effects on the engine inlet of ice buildup?
A disturbed airflow and potential FOD damage
When would you perform the icing and what with?
Shortly before take off with a de icing fluid
Is the telescopic duct short or long when the slats are retracted?
Short
When do anti-ice systems usually operate?
In-flight
What is the main advantage of an electrical temperature control circuit?
It has no mechanical parts that can wear
What circuit protects the anti-icing system from overheating?
The overheat protection circuit
On the pressure regulating valve, the valve motion stops when the downstream pressure is?
At the correct value, about 20 psi
On the pressure regulating valve when the pressure decreases below 14 psi will you get a fault light?
No because the ground sensing switch opens the circuit
What temperature does clear ice and rime ice form at?
Clear ice between zero and -10 and rime ice below -10°C
On what part of the wing do both types of ice form?
On the leading edge
Why is there only one anti ice switch for two anti-ice valves?
Because they both have to be operated at the same time
If an anti-ice valve has to be manually closed and locked, what other action must be taken?
The one on the other side must be closed and locked too
What positions can the engine anti ice valves be locked in?
In the open or closed position
What logic shots of the wing anti-ice system when the aircraft lands?
Ground to air
What two methods can be used to deice propeller blades?
Electrical heating elements and chemical deicing fluid
What two methods do we use to control the heating power in an electrically heated system?
The temperature control circuit and the power control circuit
What are the four types of probes?
Angle of attack/alpha sensors, temperature probe, pitot tube and static ports
Why is it important to heat aircraft probes?
Because with ice buildup there could be unreliable data readings
Why does a propeller rubber boot have a grooves in it if it uses a chemical deicing system?
In order to get the fluid to run along the wing at different angles
If we are to test the windscreen wiper system, what must we ensure?
That the screen is not dry
That’s what speed must we ensure that we don’t switch on the windscreen wipers?
250 knots
What is the purpose of the convert it in the windscreen wiper system?
It converts the rotating output of the motor to the cycling movement of the wiper
