B757-200
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Flight Crew Landed in Emergency Condition; General Declared Emergency
Aircraft; Human Factors
Anti ice valve right engine failed to open in icing conditions upon letdown. I directed First Officer to declare an emergency and squawk the emergency code on transponder. We retarded engine to idle getting engine vibration back into the white band. Wrong code got inserted into transponder (7500); instead of 7700. Upon inquiry from ATC as to whether cockpit was secure we gave the proper response that the cockpit was secure; and then transponder was corrected to 7700. Uneventful landing was accomplished using only engine power from the left engine.
Descending through clouds the Captain selected Engine Anti Ice on when the temperature required it. I noticed that the valve light remained illuminated on the right switch. The Captain cycled the switch a couple of times; but the light remained illuminated. We accomplished the checklist; which directed us to avoid icing conditions. By that time we had already flown out of the clouds. A few minutes later the engine vibration gauge moved into the amber range. I got the checklist out; and we accomplished it which directed us to shut down the engine. The engine was already at idle per the checklist; and we declared an emergency and requested direct. The workload became intense due to single engine procedures; and in an effort to put in the emergency [code] in the transponder; I inadvertently put in 7500 instead of 7700. I returned to the checklist; and the controller asked if the cockpit was secure. That's when I looked down; noticed the mistake and dialed in 7700. By that time; the engine vibration had decreased to the normal range; which negated the need for engine shutdown. We opted to land with the engine at idle; and we did single-engine approach procedures and landing without incident.I don't think this could have been prevented. It was an aircraft maintenance problem; and we handled it per the checklist. The workload was intense after a very long night and I dialed in the wrong transponder code which will never happen again.
B757 flight crew reports failure of the right engine anti-ice valve to open during descent. The Captain instructs the First Officer to squawk the emergency code but 7500 is entered in error. After ATC inquiry the correct code is inserted and the flight continues to destination with the right engine at idle due to vibration experienced during the descent.