Arc immobility and arc reversal phenomena limit the use, affect the design, and dictate the test procedure required for aircraft circuit interrupting equipment using magnetic arc suppression. A summary of the literature on this subject is offered. An explanation of the cause of transient arc immobility and small gap arc immobility is proposed. An addition to the consensus of theory as to the cause of arc immobility and arc reversal is suggested usefully relating arc length as a critically important factor to the understanding of these phenomena.