As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD/ROA - FLT 6591 - DURING TAXI AT 1645 HOURS ON 2-2-98, AIRCRAFT RETURNED TO GATE DUE TO LT TORQUE GAUGE FAILED. MAINTENANCE INSPECTED AND SWITCHED TO NR 2 BRIDGE ON THE LT TORQUE SIGNAL CONDITIONER. AIRCRAFT GROUND RUN, OPS CHECK OK. AIRCRAFT RELEASED AND APPROVED FOR RETURN TO SERVICE. (X)