Type I for 21+ years now @ 2 injections/day. Great advice given here in recommending slight elevation of mg/dl to about 150. Adrenaline usually depletes glucose levels a bit. Haven't run into any barriers to speak of, but expect to be declined if you ever apply for tandem rating. My primary AFF instructor was stripped of his tandem privileges upon disclosing his diagnosis of Type II to USPA. If the FAA has indeed become more lenient on Class 3 med requirements, hopefully USPA will allow him to resume his tandem activities.
