Pilots reported to ATC that the cabin crew reported the problem as an engine fire but they saw no engine problems from their instruments. With the loss of ducting should they not have lost thrust on the right side, and also the drag of the open covers should have been an indicator. Is the Airbus automation enough to compensate to the point where the pilots felt and saw no indication of a problem? As an engineer on land bound mobile equipment I remember one of our first production intent engines with FADEC controls being assembled with a timing gear assembled one tooth out of time. The FADEC compensated so it passed the factory dyno test, engine was installed in a machine, operated perfectly until at 37.3 hours valves bouncing off piston tops broke a valve head off and things went bust. New technology can cover a lot of mistakes - for awhile.