Mi-8 Anti-Ice System

[MFG62 Joker]

Trying to understand the purpose of 

8, 9 and 11 in the picture:

I understand that the radio-isotopic sensor РИО-3 sends signal to different parts of the system.

The switch (9) does what? Is it supposed to stay down or up?

What is the purpose for the pushbutton (8)?

What does the indicator lamp (11) tell me?

 

What is the procedures around these 3 items?

 

Any hint to documentation will help. The only documentation I found now is about SO-121VM detector type.

Edited December 10, 2020 by I.ZG15_FALKE

[sLYFa]

The RIO-3 is the ice detector on the Mi-8 (and a lot of ther soviet AC). It has its own heating system which keeps it at proper operating temperatures.

Button 8 tests the RIO-3 heating system, light 11 indicates a succesful test of the RIO-3 heater. Switch 9 controls whether the RIO-3 heating system is activated automatically (I don't know exactly under which conditions though) or manually

[MFG62 Joker]

great, thanks sLYFa

 

here

https://forums.eagle.ru/topic/128006-how-it-works-mi-8-ice-protection-system/

I  found this detail, great stuff!!

 

When the ICING signal is generated, the vibrating head of the ice detector is heated for 8±2 seconds in order to remove ice buildup.
•After this time delay, the heating of the ice detector head will cease. If the aircraft remains in icing conditions, ice will once again begin to build up on the ice detector head.
•At the same time that the ICING signal is generated, another timer lasting 140±40 seconds is initiated. For the duration of this timer, the “ICING” annunciator will remain illuminated and automatic anti-icing will continue.

[AlphaOneSix]

The SO-121 detector works by vibrating. The more ice that builds up on the detector, the frequency of vibration decreases, and at some point it triggers the ICING signal and starts the automatic processes for ice removal. The RIO-3 uses a small about of radioactive material, with a sensor that detects that radioactivity. The buildup of ice blocks the radioisotopes from being detected by the sensor, and once the amount of detected radiation drops to a certain level, it sends the ICING signal.

 

Regardless of which detector is in use, once an ICING signal is generated, the detector itself is heated to remove the ice buildup. Once the cycle is completed, ice can start building up again, which would start the cycle all over again.