We have received several reports from the field that mag switches allowing the removal of the key while in the left, right or both positions may be the fault of the key and not the switch. In each report this condition was experienced while using duplicate keys. Anyone with a mag switch that allows the key to be removed in any position except the off position should have the switch checked with the original key (if available) before replacing the switch. Future duplicate keys should be checked for this condition before a member is allowed to posses one. The following is a excerpt from an email received concerning this issue:
"The culprit may not be the ignition switch... it may be the individual key.
There is apparently a lock-ring within the ignition switch barrel that is designed to hold a key in the switch when the key is rotated to the RT, LT, BOTH, and START positions. There apparently is an extra tooth at the tip of Cessna ignition keys to engage this lock-ring. So far Sq 129 has found four keys where this last tooth is missing or worn down... these keys pull out of the ignition switch in other than the OFF position. These keys are copies -- or copies of copies -- where the duplication process inadvertently may have ground off this last tooth or it may have just worn down over time.