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Posted

Hi Folks,

 

Please could you let us know the exams required for RA Aus? And, is all the content covered in Bob Tait's 'RAA Cross Country Book'?

 

Thanks,

 

Stu

 

 

Posted

Hi Stu,

 

Air  law is one,

 

human factors,

 

Basic aeronautical knowledge,

 

Aircraft radio operation,

 

usually befor you solo

 

I have found some books better than others to understand.

 

ask your local school what they require .

 

Clinton

 

 

  • Like 1
Posted

RAA BAK test

 

I got caught on the question of.

 

"What causes icing"

 

I'll wait to get a few answers, before I tell what was on the correct page.

 

spacesailor

 

 

Posted
How to make and decorate cakes and the occasions on which they are required. Whoops, wrong forum!

Ahhh, obviously trying to  earn more brownie points by doing the supplemental exam RAA BAKing test..........

 

sorry?

 

 

Posted

"Carburettor icing is more likely at partial power settings because of the cooling effect of a partly-closed throttle butterfly."

 

from CASA web site.

 

That's the spelling I took for,: ICING .

 

spacesailor

 

 

Posted
RAA BAK test

I got caught on the question of.

 

"What causes icing"

 

I'll wait to get a few answers, before I tell what was on the correct page.

 

spacesailor

Moisture 

 

 

Posted

Perhaps the question could have been worded, What is the essential element/requirement for icing to occur.? Moisture doesn't CAUSE icing. neither does a temp below 0 degrees C. You can have moisture (water vapour)  below 0 degres C without condensation nuclei and you still won't get moisture condensing out .. The question is low quality and unhelpful to the understanding of and practical avoidance of  piston engine icing in aircraft. Nev

 

 

Posted

This topic raises a few questions

 

was it referring to airframe icing?

 

was it referring to carby icing?

 

here is the definition I found which provided the answer “ moisture “

 

Icing conditions exist when the air contains droplets of supercooled liquid water; icing conditions are characterized quantitatively by the average droplet size, the liquid water content and the air temperature

 

Cheers 

 

 

Posted

The question read "what causes icing"

 

Kununurra Is correct, !

 

I had read CASA's definition, which said

 

"Carburettor icing is of particular concern because, unlike airframe icing, the risk of ice build-up in the carburettor can be high even with no visible moisture and an OAT of up to 38°C.

 

Carburettor icing occurs when the air temperature adiabatically decreases sufficiently to condense water vapour and for the localised air temperature to reduce below freezing. Ice builds up as the chilled condensed water makes contact with localised surfaces, such as the butterfly valve and the venturi walls. Carburettors experience additional cooling because of the evaporation of fuel. Furthermore, the risk of carburettor icing is significantly increased at partial power settings (for example, when power is reduced during descent), because of the cooling effect of a partly-closed throttle."

 

The answer given was simply :Moisture causes icing:

 

Pity Darwin with super high moisture.

 

but

 

Great flying in Mcmurdo dry valley antarctica, if your fuel is still a liquid.

 

adiabatically ? I wonder what the bureaucrats mean.

 

spacesailor

 

 

Posted

P1 V1 /T1 is a constant. Universal GAS equation. IF that's a direct quote from CASA,  it could have been expressed better. The latent heat of vapourisation of the fuel is probably of a greater effect than adiabatic expansion of the gas at near closed throttle. The older drip system (  metered multi point  low pressure)   fuel injection has a throttle body   and no fuel near it and hardly ever gets ice forming in the throttle area. You can also get impact (rhyme) ice on the  intake filter area, but you will be getting icing on the airframe as well at the same time.. Some carbs spray alcohol down the intakes to keep ice from forming. as distinct from water meth for power enhancement. That's for aircraft certified for flight in icing conditions which OUR planes are not.. YOUR carb ice system must have adequate heat available to do the job  as designed when required though and be fully applied when used to be effective while the engine has enough heat  in  it to provide the heat needed to do the job. unless an independent source like electric is employed  People are still crashing aeroplanes because of carb icing...Nev

 

 

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