These instruments display the current timing of each PMag, along with other ignition “health related” items, and include built-in warnings.
The EI Commanders are located on the overhead just below the overhead switches. Their custom mounts are slanted and tilted toward the pilot for easier viewing at a glance.
The above photo was taken is right after power up, but before engine start. After start, the advance at idle will be 19.6 degrees.
My two main reasons for installing the EI Commanders were that I can use them to set the PMag timing parameters right from the cockpit, and I can observe the actual engine advance being used by each of the 4 PMags.
For safety, I only change the settings when on the ground and with the engines off. Then I verify the settings one more time.
I wanted the benefits of electronic ignitions, but since I had never flown with electronic ignitions before, I wanted some reassurance that they were performing as advertised. The EI Commanders provide me with that reassurance, and the peace of mind that all is well with the electronic ignitions.