There are many interesting ideas here, every one of which is completely incorrect except for Bobby and Midlife. They are both accurate in their statements.
Seeking advice or any sort of interpretation at the FSDO level is folly and an exercise in futility. The FSDO level is not authorized to provide this information, and is very often misinformed. Seeking this advice from a designated examiner is one step worse...don't waste your time.
If your instructor certificate has expired, the only legal way in which to proceed is reinstatement. This requires a practical test. You may take the practical test for any rating attached to your flight instructor certificate, or you may take the practical for a new rating. Adding a new category such as helicopter, for example.
If you hold multiple ratings, you do NOT need to take the practical test for each rating. Only one. If you are an instructor in airplanes, gliders, and helicopters, you may take the practical test in any one of them.
Seeking advice or any sort of interpretation at the FSDO level is folly and an exercise in futility. The FSDO level is not authorized to provide this information, and is very often misinformed. Seeking this advice from a designated examiner is one step worse...don't waste your time.
If your instructor certificate has expired, the only legal way in which to proceed is reinstatement. This requires a practical test. You may take the practical test for any rating attached to your flight instructor certificate, or you may take the practical for a new rating. Adding a new category such as helicopter, for example.
If you hold multiple ratings, you do NOT need to take the practical test for each rating. Only one. If you are an instructor in airplanes, gliders, and helicopters, you may take the practical test in any one of them.