[JudgeMingus]

On the filter open/closed settings:

The filter had two positions, open and closed.
It was closed for take-off and landing, and open at all other times.
I can't see much use for a 'partially open' setting - only keep half the sand out of the engine? hock:

Maybe the best option for linkage would be the flaps: filter closed for take-off setting or greater, open otherwise...