Something I've often wondered about. Always considered the 212/412 OK with the inertial separators but wondered about the 76 at times when driving through heavy rain. Has happened to fixed wing and in particular remember it being the official finding of the crash of a Metro. There was also the famous incident where a 737 had both flame out in rain and dead sticked on a levee near New Orleans (without damage).
Edited to add: You may find the following paper of interest - 32Mb download.
http://ftp.rta.nato.int/public//PubF...AGARDAR332.pdf