Quote: All of the testing and research of this accident has been conducted
on Boeing Model 777-200 and -300 series airplanes, equipped with Rolls-
Royce Model RB211-TRENT 800 series engines. Initial review of 777 other
airplane engine combinations has not revealed the same vulnerability to
the identified unsafe condition. End Quote.
Sounds like they are reasonably sure where the blockage occured and its somewhere specific to airframes plumbed for RR engines. Why wouldn't a similar release of ice be a hazard to other engines?
Edit: I was asked to post the source of the above quote. It came from this document posted earlier in this thread by "Precept"...
http://www.pprune.org/4391725-post1975.html
Justia Regulation Tracker Airworthiness Directives: Boeing Model 777-200 and -300 Series Airplanes Equipped with Rolls-Royce Model RB211-TRENT 800 Series Engines, - Federal Aviation Administration - 52909?52911 [E8?21138]