B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Weight And Balance
Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
As we were climbing thru FL250 to cruise altitude FL340 the right engine EGT gauge began to fluctuate. Although never above normal EGT range the fluctuations occasionally ceased with either a normal reading or no reading at all. We then selected the standby engine indicators and the right EGT reading was available and normal. We reviewed all appropriate checklists and other onboard references--MEL; etc.--and advised Dispatch and Maintenance via ACARS. Maintenance responded to 'continue if ALL engine readings were available.' With the standby engine indicator available; they were. Prior to ETOPS airspace; however; the standby right engine EGT indicator also became inoperative. Without EGT available and per ETOPS requirements; we diverted/returned to our departure airport. This aircraft has no fuel dump capability and to burn fuel down to MSLW [Maximum Structural Landing Weight] would have taken 3.5 hours. We contacted the company and; after all checklists were accomplished; decided to land overweight at 320;000 pounds with Flaps 30; ref of 147 and autobrakes set to position three. Landing rate of descent was normal at less than 300 fpm. Due to the overweight landing we declared an emergency with men and equipment standing by.
A B767-300 westbound for Hawaii had to return to its departure airport when both the normal and standby sources of EGT for the right engine failed prior to entering ETOPS airspace.