As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HLN - FLT 2585 - LEFT ENGINE BYPASS LIGHT CAME ON. TORQUE REDUCED TO 35 PERCENT, THEN BYPASS LIGHT CYCLED ON AND OFF. CREW DECLARED EMERGENCY AND RETURNED TO HELENA. LEFT ENGINE SRL COMPUTER FAILURE. SRL COMPUTER WAS DEFERRED PER MEL, FLIGHT RESUMED AND COMPLETED WITH NO FURTHER PROBLEM. (X)