How is a flangeless instrument case mounted in an instrument panel?

A flangeless instrument case is mounted in an instrument panel by utilizing an expanding-type clamp that is secured to the back of the panel. This method is effective because it allows a secure fit without the need for a flange, which can increase installation simplicity and decrease instrument panel thickness. The expanding clamp mechanism grips the case when it is installed, ensuring that the instrument remains firmly in place during operation, accommodating vibration and movement typically encountered in flight.

While other methods like screws or adhesive might be used in different scenarios, they do not provide the same level of adaptability and are typically not employed with flangeless designs. Rubber grommets, on the other hand, primarily serve to absorb vibration and shock rather than secure the instrument directly within the panel. Thus, the expanding-type clamp is the most suitable and effective method for this particular mounting approach.