A B757-200 EXPERIENCED FAILURE OF THE ENG ELECTRONIC LIMIT CTL AND THE ELECTRONIC ENG CTL ON TKOF CAUSING THE #2 ENG TO OVERTEMP AND OVERSPD.

Narrative

WE WERE BRIEFED BY THE INBOUND CAPT THAT THE R ENG EEC AND ELC FAILED DURING HIS DSCNT. MAINT COULD FIND NOTHING WRONG. WE HAD THE SAME PROB GOING INTO JAC. WE CONSULTED WITH BOTH DISPATCH AND TECHNICIAN. A DECISION WAS MADE TO START UP AND IF THE SYS WORKED; FINE. IF THEY DID NOT; THEY WERE FLC PLACARDABLE. TECHNICIAN TOLD US THAT IF ONE EEC FAILED; THE AUTOTHROTTLES WOULD ALSO DISCONNECT. HE ADVISED US THAT IN THIS SIT; TURNING BOTH EEC SWITCHES OFF WOULD ALLOW THE USE OF THE AUTOTHROTTLES. DURING THE TKOF; THE R ENG N2 OVERSPED. I ASKED THE FO TO CONCENTRATE ON SETTING THE R ENG PWR. AFTER TKOF; THE R ENG OVERTEMPED AND OVERSPED AGAIN. TO KEEP THE ENG WITHIN LIMITS; THE PWR HAD TO BE REDUCED SUBSTANTIALLY. THE ENG WAS SO DIFFICULT TO CTL AND SET TKOF PWR; THAT I THINK WE SHOULD ALLOW THE 2 SYS TO BE INOP AND THE ACFT FLOWN ON MEL AUTH. THIS SIT IS OK ON LONG RWYS; BUT IS COMPLETELY UNACCEPTABLE WHEN RWY LIMITED. TECHNICIAN TOLD US THAT IN THIS SIT; THE ENG BLEED SYS GOES INTO A STANDBY MODE THAT CHANGES ALL THE ENG PARAMETERS. THAT IS WHY THEY THINK THE N2 AND EGT EXCEEDED LIMITS BEFORE EPR AND N1. CRUISE PARAMETERS WERE MUCH REDUCED ON THE R ENG. IE; THE RPM AND EGT WERE MUCH HIGHER THAN THE L ENG FOR THE SAME PWR.