Originally Posted by
Echo Romeo
Just one thing, there is a small pipe coming out of the encoder which looks as though it's tee'd into the static air system, what is it's function?
Um - an encoder's job is to convert flight level (ie - altitude at standard pressure) into a code. It does this by measuring the air pressure as supplied through the static pressure line.
Of course - it could just use the air pressure from around the encoder. However this would be subject to various errors (the air in the cockpit will be a slightly different pressure than outside) - hence why you have a static air pressure system.