Until the 777 development there were no FAA standards concerning water injestion tolerance .. some engines like the CF-6 are naturally tolerant to water - other engines were very intolerant to water such as the CFM-56. However, the good old boys at Boeing solved this when it appeared on the 737 dual engine flame out - with their "cutback-splitter" fix documented in US patent 5431535 - " Foreign matter diverter systems for turbofan engines ". Since that time - the Airbus A320 & A340 have benefited from this technology as well - since they all use the same engine - more or less .. Today, this is wellunderstood and is further documented in the FAA's engineering design - certification compliance methods for turbomachinery ..