Download the Full November 2016 Issue PDF

These things don't last forever. The baking 200-degree temperatures on top of a glareshield mean you'll likely be faced with a repair or replacement. Generally, the main part that fails (ultimately leaking) is the rear rubber expansion/contraction diaphragm. Since the fluid in the compass needs room to expand and contract with temperature changes, a sealing membrane keeps the fluid inside. These simple devices arent packed with components. Typically, it takes just four small screws to expose the diaphragm on the rear compass housing.

Aviation Consumer November 2016