Quite simple really:JAR–FCL 1.355 FI(A) – Revalidation and renewal says:
(a) For revalidation of a FI(A) rating the
holder shall fulfill two of the following three
requirements:
(1) completed at least 100 hours of
flight instruction on aeroplanes as FI, CRI, IRI
or as examiner during the period of validity of
the rating, including at least 30 hours of flight
instruction within the 12 months preceding
the expiry date of the FI rating
3 years ago it was reduced to
50 hours and
15 hours
Helicopter FIs were notified in an AIC; Aeroplane FIs by Long Term Exemption, that nobody had ever heard of and now it has changed to the ORS4 Series. Nice to see a consistent approach to notifying important information!