B757 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 100; Flight Crew Total 20000; Flight Crew Type 9300
Aircraft Equipment Problem Critical
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport
Aircraft
Departed with one fire detection loop on right engine deferred inoperable. Climbing through 25;000 FT right fire warning light and bell came on for 20 seconds and then went out. All engine indications were normal. Right engine fire warning activated again for a few seconds and went out. Status message showed both fire detection loops on right engine were inoperable. Contacted Dispatch and returned.
B757 Captain reports being dispatched with one fire detection loop in the right engine deferred. During climb the right engine fire warning light and bell activated and stopped two times. EICAS status indicated both fire loops failed and the crew elects to return to the departure airport.