No I'm not saying you should disregard a passenger's concern but...
If all my engine parameters are normal, if all my bleeds are normal if the aircraft's engine respond normally and the aircraft itself feels normal and if I have no fire warnings going off in the cockpit I would certainly not shut down or declare an emergency just because a passenger said he saw a fire.
An aircraft doesn't fall out of the sky because of an engine fire. In the above circumstance I would certainly delegate a crew member preferably the other pilot to have a look at this passenger’s concern.
Just like wing icing/contamination, if a passenger or another crew member felt concerned about possible contamination on the wings prior to takeoff then having a crew member take a look and address this passenger's concern would be totally normal.
Last edited by Jet Jockey A4; 15th Apr 2013 at 14:51.